diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 292bfe51340db..3fba2894002cc 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -2112,7 +2112,7 @@ namespace ts {
                             // Nothing to do
                             break;
                         default:
-                            Debug.fail("Unknown special property assignment kind");
+                            Debug.fail("Unknown binary expression special property assignment kind");
                     }
                     return checkStrictModeBinaryExpression(<BinaryExpression>node);
                 case SyntaxKind.CatchClause:
@@ -2188,6 +2188,19 @@ namespace ts {
                     return bindFunctionExpression(<FunctionExpression>node);
 
                 case SyntaxKind.CallExpression:
+                    const assignmentKind = getAssignmentDeclarationKind(node as CallExpression);
+                    switch (assignmentKind) {
+                        case AssignmentDeclarationKind.ObjectDefinePropertyValue:
+                            return bindObjectDefinePropertyAssignment(node as BindableObjectDefinePropertyCall);
+                        case AssignmentDeclarationKind.ObjectDefinePropertyExports:
+                            return bindObjectDefinePropertyExport(node as BindableObjectDefinePropertyCall);
+                        case AssignmentDeclarationKind.ObjectDefinePrototypeProperty:
+                            return bindObjectDefinePrototypeProperty(node as BindableObjectDefinePropertyCall);
+                        case AssignmentDeclarationKind.None:
+                            break; // Nothing to do
+                        default:
+                            return Debug.fail("Unknown call expression assignment declaration kind");
+                    }
                     if (isInJSFile(node)) {
                         bindCallExpression(<CallExpression>node);
                     }
@@ -2351,6 +2364,22 @@ namespace ts {
             return true;
         }
 
+        function bindObjectDefinePropertyExport(node: BindableObjectDefinePropertyCall) {
+            if (!setCommonJsModuleIndicator(node)) {
+                return;
+            }
+            const symbol = forEachIdentifierInEntityName(node.arguments[0], /*parent*/ undefined, (id, symbol) => {
+                if (symbol) {
+                    addDeclarationToSymbol(symbol, id, SymbolFlags.Module | SymbolFlags.Assignment);
+                }
+                return symbol;
+            });
+            if (symbol) {
+                const flags = SymbolFlags.Property | SymbolFlags.ExportValue;
+                declareSymbol(symbol.exports!, symbol, node, flags, SymbolFlags.None);
+            }
+        }
+
         function bindExportsPropertyAssignment(node: BinaryExpression) {
             // When we create a property via 'exports.foo = bar', the 'exports.foo' property access
             // expression is the declaration
@@ -2458,6 +2487,11 @@ namespace ts {
             bindPropertyAssignment(lhs.expression, lhs, /*isPrototypeProperty*/ false);
         }
 
+        function bindObjectDefinePrototypeProperty(node: BindableObjectDefinePropertyCall) {
+            const namespaceSymbol = lookupSymbolForPropertyAccess((node.arguments[0] as PropertyAccessExpression).expression as EntityNameExpression);
+            bindPotentiallyNewExpandoMemberToNamespace(node, namespaceSymbol, /*isPrototypeProperty*/ true);
+        }
+
         /**
          * For `x.prototype.y = z`, declare a member `y` on `x` if `x` is a function or class, or not declared.
          * Note that jsdoc preceding an ExpressionStatement like `x.prototype.y;` is also treated as a declaration.
@@ -2476,6 +2510,12 @@ namespace ts {
             bindPropertyAssignment(constructorFunction, lhs, /*isPrototypeProperty*/ true);
         }
 
+        function bindObjectDefinePropertyAssignment(node: BindableObjectDefinePropertyCall) {
+            let namespaceSymbol = lookupSymbolForPropertyAccess(node.arguments[0]);
+            const isToplevel = node.parent.parent.kind === SyntaxKind.SourceFile;
+            namespaceSymbol = bindPotentiallyMissingNamespaces(namespaceSymbol, node.arguments[0], isToplevel, /*isPrototypeProperty*/ false);
+            bindPotentiallyNewExpandoMemberToNamespace(node, namespaceSymbol, /*isPrototypeProperty*/ false);
+        }
 
         function bindSpecialPropertyAssignment(node: BinaryExpression) {
             const lhs = node.left as PropertyAccessEntityNameExpression;
@@ -2507,16 +2547,12 @@ namespace ts {
             bindPropertyAssignment(node.expression, node, /*isPrototypeProperty*/ false);
         }
 
-        function bindPropertyAssignment(name: EntityNameExpression, propertyAccess: PropertyAccessEntityNameExpression, isPrototypeProperty: boolean) {
-            let namespaceSymbol = lookupSymbolForPropertyAccess(name);
-            const isToplevel = isBinaryExpression(propertyAccess.parent)
-                ? getParentOfBinaryExpression(propertyAccess.parent).parent.kind === SyntaxKind.SourceFile
-                : propertyAccess.parent.parent.kind === SyntaxKind.SourceFile;
+        function bindPotentiallyMissingNamespaces(namespaceSymbol: Symbol | undefined, entityName: EntityNameExpression, isToplevel: boolean, isPrototypeProperty: boolean) {
             if (isToplevel && !isPrototypeProperty && (!namespaceSymbol || !(namespaceSymbol.flags & SymbolFlags.Namespace))) {
                 // make symbols or add declarations for intermediate containers
                 const flags = SymbolFlags.Module | SymbolFlags.Assignment;
                 const excludeFlags = SymbolFlags.ValueModuleExcludes & ~SymbolFlags.Assignment;
-                namespaceSymbol = forEachIdentifierInEntityName(propertyAccess.expression, namespaceSymbol, (id, symbol, parent) => {
+                namespaceSymbol = forEachIdentifierInEntityName(entityName, namespaceSymbol, (id, symbol, parent) => {
                     if (symbol) {
                         addDeclarationToSymbol(symbol, id, flags);
                         return symbol;
@@ -2528,6 +2564,10 @@ namespace ts {
                     }
                 });
             }
+            return namespaceSymbol;
+        }
+
+        function bindPotentiallyNewExpandoMemberToNamespace(declaration: PropertyAccessEntityNameExpression | CallExpression, namespaceSymbol: Symbol | undefined, isPrototypeProperty: boolean) {
             if (!namespaceSymbol || !isExpandoSymbol(namespaceSymbol)) {
                 return;
             }
@@ -2537,10 +2577,19 @@ namespace ts {
                 (namespaceSymbol.members || (namespaceSymbol.members = createSymbolTable())) :
                 (namespaceSymbol.exports || (namespaceSymbol.exports = createSymbolTable()));
 
-            const isMethod = isFunctionLikeDeclaration(getAssignedExpandoInitializer(propertyAccess)!);
+            const isMethod = isFunctionLikeDeclaration(getAssignedExpandoInitializer(declaration)!);
             const includes = isMethod ? SymbolFlags.Method : SymbolFlags.Property;
             const excludes = isMethod ? SymbolFlags.MethodExcludes : SymbolFlags.PropertyExcludes;
-            declareSymbol(symbolTable, namespaceSymbol, propertyAccess, includes | SymbolFlags.Assignment, excludes & ~SymbolFlags.Assignment);
+            declareSymbol(symbolTable, namespaceSymbol, declaration, includes | SymbolFlags.Assignment, excludes & ~SymbolFlags.Assignment);
+        }
+
+        function bindPropertyAssignment(name: EntityNameExpression, propertyAccess: PropertyAccessEntityNameExpression, isPrototypeProperty: boolean) {
+            let namespaceSymbol = lookupSymbolForPropertyAccess(name);
+            const isToplevel = isBinaryExpression(propertyAccess.parent)
+                ? getParentOfBinaryExpression(propertyAccess.parent).parent.kind === SyntaxKind.SourceFile
+                : propertyAccess.parent.parent.kind === SyntaxKind.SourceFile;
+            namespaceSymbol = bindPotentiallyMissingNamespaces(namespaceSymbol, propertyAccess.expression, isToplevel, isPrototypeProperty);
+            bindPotentiallyNewExpandoMemberToNamespace(propertyAccess, namespaceSymbol, isPrototypeProperty);
         }
 
         /**
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index eca967ce8282d..ea5e27c2c9e5a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4881,7 +4881,7 @@ namespace ts {
             let jsdocType: Type | undefined;
             let types: Type[] | undefined;
             for (const declaration of symbol.declarations) {
-                const expression = isBinaryExpression(declaration) ? declaration :
+                const expression = (isBinaryExpression(declaration) || isCallExpression(declaration)) ? declaration :
                     isPropertyAccessExpression(declaration) ? isBinaryExpression(declaration.parent) ? declaration.parent : declaration :
                         undefined;
                 if (!expression) {
@@ -4897,9 +4897,11 @@ namespace ts {
                         definedInMethod = true;
                     }
                 }
-                jsdocType = getJSDocTypeFromAssignmentDeclaration(jsdocType, expression, symbol, declaration);
+                if (!isCallExpression(expression)) {
+                    jsdocType = getJSDocTypeFromAssignmentDeclaration(jsdocType, expression, symbol, declaration);
+                }
                 if (!jsdocType) {
-                    (types || (types = [])).push(isBinaryExpression(expression) ? getInitializerTypeFromAssignmentDeclaration(symbol, resolvedSymbol, expression, kind) : neverType);
+                    (types || (types = [])).push((isBinaryExpression(expression) || isCallExpression(expression)) ? getInitializerTypeFromAssignmentDeclaration(symbol, resolvedSymbol, expression, kind) : neverType);
                 }
             }
             let type = jsdocType;
@@ -4960,7 +4962,32 @@ namespace ts {
         }
 
         /** If we don't have an explicit JSDoc type, get the type from the initializer. */
-        function getInitializerTypeFromAssignmentDeclaration(symbol: Symbol, resolvedSymbol: Symbol | undefined, expression: BinaryExpression, kind: AssignmentDeclarationKind) {
+        function getInitializerTypeFromAssignmentDeclaration(symbol: Symbol, resolvedSymbol: Symbol | undefined, expression: BinaryExpression | CallExpression, kind: AssignmentDeclarationKind) {
+            if (isCallExpression(expression)) {
+                if (resolvedSymbol) {
+                    return getTypeOfSymbol(resolvedSymbol); // This shouldn't happen except under some hopefully forbidden merges of export assignments and object define assignments
+                }
+                const objectLitType = checkExpressionCached((expression as BindableObjectDefinePropertyCall).arguments[2]);
+                const valueType = getTypeOfPropertyOfType(objectLitType, "value" as __String);
+                if (valueType) {
+                    return valueType;
+                }
+                const getFunc = getTypeOfPropertyOfType(objectLitType, "get" as __String);
+                if (getFunc) {
+                    const getSig = getSingleCallSignature(getFunc);
+                    if (getSig) {
+                        return getReturnTypeOfSignature(getSig);
+                    }
+                }
+                const setFunc = getTypeOfPropertyOfType(objectLitType, "set" as __String);
+                if (setFunc) {
+                    const setSig = getSingleCallSignature(setFunc);
+                    if (setSig) {
+                        return getTypeOfFirstParameterOfSignature(setSig);
+                    }
+                }
+                return anyType;
+            }
             const type = resolvedSymbol ? getTypeOfSymbol(resolvedSymbol) : getWidenedLiteralType(checkExpressionCached(expression.right));
             if (type.flags & TypeFlags.Object &&
                 kind === AssignmentDeclarationKind.ModuleExports &&
@@ -5212,7 +5239,7 @@ namespace ts {
             }
             let type: Type | undefined;
             if (isInJSFile(declaration) &&
-                (isBinaryExpression(declaration) || isPropertyAccessExpression(declaration) && isBinaryExpression(declaration.parent))) {
+                (isCallExpression(declaration) || isBinaryExpression(declaration) || isPropertyAccessExpression(declaration) && isBinaryExpression(declaration.parent))) {
                 type = getWidenedTypeFromAssignmentDeclaration(symbol);
             }
             else if (isJSDocPropertyLikeTag(declaration)
@@ -16179,6 +16206,31 @@ namespace ts {
                 getAssignmentDeclarationKind(container.parent.parent.parent) === AssignmentDeclarationKind.Prototype) {
                 return (container.parent.parent.parent.left as PropertyAccessExpression).expression;
             }
+            // Object.defineProperty(x, "method", { value: function() { } });
+            // Object.defineProperty(x, "method", { set: (x: () => void) => void });
+            // Object.defineProperty(x, "method", { get: () => function() { }) });
+            else if (container.kind === SyntaxKind.FunctionExpression &&
+                isPropertyAssignment(container.parent) &&
+                isIdentifier(container.parent.name) &&
+                (container.parent.name.escapedText === "value" || container.parent.name.escapedText === "get" || container.parent.name.escapedText === "set") &&
+                isObjectLiteralExpression(container.parent.parent) &&
+                isCallExpression(container.parent.parent.parent) &&
+                container.parent.parent.parent.arguments[2] === container.parent.parent &&
+                getAssignmentDeclarationKind(container.parent.parent.parent) === AssignmentDeclarationKind.ObjectDefinePrototypeProperty) {
+                return (container.parent.parent.parent.arguments[0] as PropertyAccessExpression).expression;
+            }
+            // Object.defineProperty(x, "method", { value() { } });
+            // Object.defineProperty(x, "method", { set(x: () => void) {} });
+            // Object.defineProperty(x, "method", { get() { return () => {} } });
+            else if (isMethodDeclaration(container) &&
+                isIdentifier(container.name) &&
+                (container.name.escapedText === "value" || container.name.escapedText === "get" || container.name.escapedText === "set") &&
+                isObjectLiteralExpression(container.parent) &&
+                isCallExpression(container.parent.parent) &&
+                container.parent.parent.arguments[2] === container.parent &&
+                getAssignmentDeclarationKind(container.parent.parent) === AssignmentDeclarationKind.ObjectDefinePrototypeProperty) {
+                return (container.parent.parent.arguments[0] as PropertyAccessExpression).expression;
+            }
         }
 
         function getTypeForThisExpressionFromJSDoc(node: Node) {
@@ -16741,6 +16793,10 @@ namespace ts {
                     }
                     const thisType = checkThisExpression(thisAccess.expression);
                     return thisType && getTypeOfPropertyOfContextualType(thisType, thisAccess.name.escapedText) || false;
+                case AssignmentDeclarationKind.ObjectDefinePropertyValue:
+                case AssignmentDeclarationKind.ObjectDefinePropertyExports:
+                case AssignmentDeclarationKind.ObjectDefinePrototypeProperty:
+                    return Debug.fail("Does not apply");
                 default:
                     return Debug.assertNever(kind);
             }
@@ -21132,18 +21188,52 @@ namespace ts {
             return true;
         }
 
+        function isReadonlyAssignmentDeclaration(d: Declaration) {
+            if (!isCallExpression(d)) {
+                return false;
+            }
+            if (!isBindableObjectDefinePropertyCall(d)) {
+                return false;
+            }
+            const objectLitType = checkExpressionCached(d.arguments[2]);
+            const valueType = getTypeOfPropertyOfType(objectLitType, "value" as __String);
+            if (valueType) {
+                const writableProp = getPropertyOfType(objectLitType, "writable" as __String);
+                const writableType = writableProp && getTypeOfSymbol(writableProp);
+                if (!writableType || writableType === falseType || writableType === regularFalseType) {
+                    return true;
+                }
+                // We include this definition whereupon we walk back and check the type at the declaration because
+                // The usual definition of `Object.defineProperty` will _not_ cause literal types to be preserved in the
+                // argument types, should the type be contextualized by the call itself.
+                if (writableProp && writableProp.valueDeclaration && isPropertyAssignment(writableProp.valueDeclaration)) {
+                    const initializer = writableProp.valueDeclaration.initializer;
+                    const rawOriginalType = checkExpression(initializer);
+                    if (rawOriginalType === falseType || rawOriginalType === regularFalseType) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+            const setProp = getPropertyOfType(objectLitType, "set" as __String);
+            return !setProp;
+        }
+
         function isReadonlySymbol(symbol: Symbol): boolean {
             // The following symbols are considered read-only:
             // Properties with a 'readonly' modifier
             // Variables declared with 'const'
             // Get accessors without matching set accessors
             // Enum members
+            // Object.defineProperty assignments with writable false or no setter
             // Unions and intersections of the above (unions and intersections eagerly set isReadonly on creation)
             return !!(getCheckFlags(symbol) & CheckFlags.Readonly ||
                 symbol.flags & SymbolFlags.Property && getDeclarationModifierFlagsFromSymbol(symbol) & ModifierFlags.Readonly ||
                 symbol.flags & SymbolFlags.Variable && getDeclarationNodeFlagsFromSymbol(symbol) & NodeFlags.Const ||
                 symbol.flags & SymbolFlags.Accessor && !(symbol.flags & SymbolFlags.SetAccessor) ||
-                symbol.flags & SymbolFlags.EnumMember);
+                symbol.flags & SymbolFlags.EnumMember ||
+                some(symbol.declarations, isReadonlyAssignmentDeclaration)
+            );
         }
 
         function isReferenceToReadonlyEntity(expr: Expression, symbol: Symbol): boolean {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 610cc4e61c7a7..fe31a30a30f08 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -790,7 +790,7 @@ namespace ts {
 
     export type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
 
-    export type DeclarationName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName | BindingPattern;
+    export type DeclarationName = Identifier | StringLiteralLike | NumericLiteral | ComputedPropertyName | BindingPattern;
 
     export interface Declaration extends Node {
         _declarationBrand: any;
@@ -1774,6 +1774,9 @@ namespace ts {
         arguments: NodeArray<Expression>;
     }
 
+    /** @internal */
+    export type BindableObjectDefinePropertyCall = CallExpression & { arguments: { 0: EntityNameExpression, 1: StringLiteralLike | NumericLiteral, 2: ObjectLiteralExpression } };
+
     // see: https://tc39.github.io/ecma262/#prod-SuperCall
     export interface SuperCall extends CallExpression {
         expression: SuperExpression;
@@ -4347,6 +4350,15 @@ namespace ts {
         Property,
         // F.prototype = { ... }
         Prototype,
+        // Object.defineProperty(x, 'name', { value: any, writable?: boolean (false by default) });
+        // Object.defineProperty(x, 'name', { get: Function, set: Function });
+        // Object.defineProperty(x, 'name', { get: Function });
+        // Object.defineProperty(x, 'name', { set: Function });
+        ObjectDefinePropertyValue,
+        // Object.defineProperty(exports || module.exports, 'name', ...);
+        ObjectDefinePropertyExports,
+        // Object.defineProperty(Foo.prototype, 'name', ...);
+        ObjectDefinePrototypeProperty,
     }
 
     /** @deprecated Use FileExtensionInfo instead. */
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index acaabdab9c7be..6310d299b4283 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -765,12 +765,13 @@ namespace ts {
         return info.declaration ? declarationNameToString(info.declaration.parameters[0].name) : undefined;
     }
 
-    export function getTextOfPropertyName(name: PropertyName): __String {
+    export function getTextOfPropertyName(name: PropertyName | NoSubstitutionTemplateLiteral): __String {
         switch (name.kind) {
             case SyntaxKind.Identifier:
                 return name.escapedText;
             case SyntaxKind.StringLiteral:
             case SyntaxKind.NumericLiteral:
+            case SyntaxKind.NoSubstitutionTemplateLiteral:
                 return escapeLeadingUnderscores(name.text);
             case SyntaxKind.ComputedPropertyName:
                 return isStringOrNumericLiteralLike(name.expression) ? escapeLeadingUnderscores(name.expression.text) : undefined!; // TODO: GH#18217 Almost all uses of this assume the result to be defined!
@@ -1770,7 +1771,7 @@ namespace ts {
     }
 
     export function isAssignmentDeclaration(decl: Declaration) {
-        return isBinaryExpression(decl) || isPropertyAccessExpression(decl) || isIdentifier(decl);
+        return isBinaryExpression(decl) || isPropertyAccessExpression(decl) || isIdentifier(decl) || isCallExpression(decl);
     }
 
     /** Get the initializer, taking into account defaulted Javascript initializers */
@@ -1905,12 +1906,35 @@ namespace ts {
 
     /// Given a BinaryExpression, returns SpecialPropertyAssignmentKind for the various kinds of property
     /// assignments we treat as special in the binder
-    export function getAssignmentDeclarationKind(expr: BinaryExpression): AssignmentDeclarationKind {
+    export function getAssignmentDeclarationKind(expr: BinaryExpression | CallExpression): AssignmentDeclarationKind {
         const special = getAssignmentDeclarationKindWorker(expr);
         return special === AssignmentDeclarationKind.Property || isInJSFile(expr) ? special : AssignmentDeclarationKind.None;
     }
 
-    function getAssignmentDeclarationKindWorker(expr: BinaryExpression): AssignmentDeclarationKind {
+    export function isBindableObjectDefinePropertyCall(expr: CallExpression): expr is BindableObjectDefinePropertyCall {
+            return length(expr.arguments) === 3 &&
+                isPropertyAccessExpression(expr.expression) &&
+                isIdentifier(expr.expression.expression) &&
+                idText(expr.expression.expression) === "Object" &&
+                idText(expr.expression.name) === "defineProperty" &&
+                isStringOrNumericLiteralLike(expr.arguments[1]) &&
+                isEntityNameExpression(expr.arguments[0]);
+    }
+
+    function getAssignmentDeclarationKindWorker(expr: BinaryExpression | CallExpression): AssignmentDeclarationKind {
+        if (isCallExpression(expr)) {
+            if (!isBindableObjectDefinePropertyCall(expr)) {
+                return AssignmentDeclarationKind.None;
+            }
+            const entityName = expr.arguments[0];
+            if (isExportsIdentifier(entityName) || isModuleExportsPropertyAccessExpression(entityName)) {
+                return AssignmentDeclarationKind.ObjectDefinePropertyExports;
+            }
+            if (isPropertyAccessExpression(entityName) && entityName.name.escapedText === "prototype" && isEntityNameExpression(entityName.expression)) {
+                return AssignmentDeclarationKind.ObjectDefinePrototypeProperty;
+            }
+            return AssignmentDeclarationKind.ObjectDefinePropertyValue;
+        }
         if (expr.operatorToken.kind !== SyntaxKind.EqualsToken ||
             !isPropertyAccessExpression(expr.left)) {
             return AssignmentDeclarationKind.None;
@@ -1927,7 +1951,7 @@ namespace ts {
         if (lhs.expression.kind === SyntaxKind.ThisKeyword) {
             return AssignmentDeclarationKind.ThisProperty;
         }
-        else if (isIdentifier(lhs.expression) && lhs.expression.escapedText === "module" && lhs.name.escapedText === "exports") {
+        else if (isModuleExportsPropertyAccessExpression(lhs)) {
             // module.exports = expr
             return AssignmentDeclarationKind.ModuleExports;
         }
@@ -4977,14 +5001,19 @@ namespace ts {
                 }
                 break;
             }
+            case SyntaxKind.CallExpression:
             case SyntaxKind.BinaryExpression: {
-                const expr = declaration as BinaryExpression;
+                const expr = declaration as BinaryExpression | CallExpression;
                 switch (getAssignmentDeclarationKind(expr)) {
                     case AssignmentDeclarationKind.ExportsProperty:
                     case AssignmentDeclarationKind.ThisProperty:
                     case AssignmentDeclarationKind.Property:
                     case AssignmentDeclarationKind.PrototypeProperty:
-                        return (expr.left as PropertyAccessExpression).name;
+                        return ((expr as BinaryExpression).left as PropertyAccessExpression).name;
+                    case AssignmentDeclarationKind.ObjectDefinePropertyValue:
+                    case AssignmentDeclarationKind.ObjectDefinePropertyExports:
+                    case AssignmentDeclarationKind.ObjectDefinePrototypeProperty:
+                        return (expr as BindableObjectDefinePropertyCall).arguments[1];
                     default:
                         return undefined;
                 }
diff --git a/src/services/navigationBar.ts b/src/services/navigationBar.ts
index 03d2aec13c54d..760d6e7103103 100644
--- a/src/services/navigationBar.ts
+++ b/src/services/navigationBar.ts
@@ -281,6 +281,9 @@ namespace ts.NavigationBar {
                     case AssignmentDeclarationKind.ThisProperty:
                     case AssignmentDeclarationKind.Property:
                     case AssignmentDeclarationKind.None:
+                    case AssignmentDeclarationKind.ObjectDefinePropertyValue:
+                    case AssignmentDeclarationKind.ObjectDefinePropertyExports:
+                    case AssignmentDeclarationKind.ObjectDefinePrototypeProperty:
                         break;
                     default:
                         Debug.assertNever(special);
diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 427c31e53845e..e53f568c0f417 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -368,6 +368,9 @@ namespace ts {
                 const kind = getAssignmentDeclarationKind(node as BinaryExpression);
                 const { right } = node as BinaryExpression;
                 switch (kind) {
+                    case AssignmentDeclarationKind.ObjectDefinePropertyValue:
+                    case AssignmentDeclarationKind.ObjectDefinePropertyExports:
+                    case AssignmentDeclarationKind.ObjectDefinePrototypeProperty:
                     case AssignmentDeclarationKind.None:
                         return ScriptElementKind.unknown;
                     case AssignmentDeclarationKind.ExportsProperty:
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 00b93acbba514..a7e8d3e569056 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -526,7 +526,7 @@ declare namespace ts {
     }
     type EntityName = Identifier | QualifiedName;
     type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
-    type DeclarationName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName | BindingPattern;
+    type DeclarationName = Identifier | StringLiteralLike | NumericLiteral | ComputedPropertyName | BindingPattern;
     interface Declaration extends Node {
         _declarationBrand: any;
     }
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 34b5ade8841a4..0c2485d1a2566 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -526,7 +526,7 @@ declare namespace ts {
     }
     type EntityName = Identifier | QualifiedName;
     type PropertyName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName;
-    type DeclarationName = Identifier | StringLiteral | NumericLiteral | ComputedPropertyName | BindingPattern;
+    type DeclarationName = Identifier | StringLiteralLike | NumericLiteral | ComputedPropertyName | BindingPattern;
     interface Declaration extends Node {
         _declarationBrand: any;
     }
diff --git a/tests/baselines/reference/checkExportsObjectAssignProperty.errors.txt b/tests/baselines/reference/checkExportsObjectAssignProperty.errors.txt
new file mode 100644
index 0000000000000..266c2180a685f
--- /dev/null
+++ b/tests/baselines/reference/checkExportsObjectAssignProperty.errors.txt
@@ -0,0 +1,110 @@
+tests/cases/conformance/jsdoc/validator.ts(17,4): error TS2540: Cannot assign to 'readonlyProp' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validator.ts(18,4): error TS2540: Cannot assign to 'readonlyAccessor' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validator.ts(19,1): error TS2322: Type '"no"' is not assignable to type 'number'.
+tests/cases/conformance/jsdoc/validator.ts(20,1): error TS2322: Type '"no"' is not assignable to type 'number'.
+tests/cases/conformance/jsdoc/validator.ts(21,1): error TS2322: Type '0' is not assignable to type 'string'.
+tests/cases/conformance/jsdoc/validator.ts(37,4): error TS2540: Cannot assign to 'readonlyProp' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validator.ts(38,4): error TS2540: Cannot assign to 'readonlyAccessor' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validator.ts(39,1): error TS2322: Type '0' is not assignable to type 'string'.
+tests/cases/conformance/jsdoc/validator.ts(40,1): error TS2322: Type '"no"' is not assignable to type 'number'.
+tests/cases/conformance/jsdoc/validator.ts(41,1): error TS2322: Type '0' is not assignable to type 'string'.
+
+
+==== tests/cases/conformance/jsdoc/validator.ts (10 errors) ====
+    import "./";
+    
+    import m1 = require("./mod1");
+    
+    m1.thing;
+    m1.readonlyProp;
+    m1.rwAccessors;
+    m1.readonlyAccessor;
+    m1.setonlyAccessor;
+    
+    // allowed assignments
+    m1.thing = 10;
+    m1.rwAccessors = 11;
+    m1.setonlyAccessor = "yes";
+    
+    // disallowed assignments
+    m1.readonlyProp = "name";
+       ~~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'readonlyProp' because it is a constant or a read-only property.
+    m1.readonlyAccessor = 12;
+       ~~~~~~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'readonlyAccessor' because it is a constant or a read-only property.
+    m1.thing = "no";
+    ~~~~~~~~
+!!! error TS2322: Type '"no"' is not assignable to type 'number'.
+    m1.rwAccessors = "no";
+    ~~~~~~~~~~~~~~
+!!! error TS2322: Type '"no"' is not assignable to type 'number'.
+    m1.setonlyAccessor = 0;
+    ~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '0' is not assignable to type 'string'.
+    
+    import m2 = require("./mod2");
+    
+    m2.thing;
+    m2.readonlyProp;
+    m2.rwAccessors;
+    m2.readonlyAccessor;
+    m2.setonlyAccessor;
+    
+    // allowed assignments
+    m2.thing = "ok";
+    m2.rwAccessors = 11;
+    m2.setonlyAccessor = "yes";
+    
+    // disallowed assignments
+    m2.readonlyProp = "name";
+       ~~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'readonlyProp' because it is a constant or a read-only property.
+    m2.readonlyAccessor = 12;
+       ~~~~~~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'readonlyAccessor' because it is a constant or a read-only property.
+    m2.thing = 0;
+    ~~~~~~~~
+!!! error TS2322: Type '0' is not assignable to type 'string'.
+    m2.rwAccessors = "no";
+    ~~~~~~~~~~~~~~
+!!! error TS2322: Type '"no"' is not assignable to type 'number'.
+    m2.setonlyAccessor = 0;
+    ~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '0' is not assignable to type 'string'.
+    
+==== tests/cases/conformance/jsdoc/mod1.js (0 errors) ====
+    Object.defineProperty(exports, "thing", { value: 42, writable: true });
+    Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false });
+    Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+    Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } });
+    Object.defineProperty(exports, "setonlyAccessor", {
+        /** @param {string} str */
+        set(str) {
+            this.rwAccessors = Number(str) 
+        }
+    });
+    
+==== tests/cases/conformance/jsdoc/mod2.js (0 errors) ====
+    Object.defineProperty(module.exports, "thing", { value: "yes", writable: true });
+    Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false });
+    Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+    Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } });
+    Object.defineProperty(module.exports, "setonlyAccessor", {
+        /** @param {string} str */
+        set(str) {
+            this.rwAccessors = Number(str) 
+        }
+    });
+    
+==== tests/cases/conformance/jsdoc/index.js (0 errors) ====
+    /**
+     * @type {number}
+     */
+    const q = require("./mod1").thing;
+    
+    /**
+     * @type {string}
+     */
+    const u = require("./mod2").thing;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/checkExportsObjectAssignProperty.symbols b/tests/baselines/reference/checkExportsObjectAssignProperty.symbols
new file mode 100644
index 0000000000000..d33e2de1e209a
--- /dev/null
+++ b/tests/baselines/reference/checkExportsObjectAssignProperty.symbols
@@ -0,0 +1,276 @@
+=== tests/cases/conformance/jsdoc/validator.ts ===
+import "./";
+
+import m1 = require("./mod1");
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+
+m1.thing;
+>m1.thing : Symbol(m1["thing"], Decl(mod1.js, 0, 0))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>thing : Symbol(m1["thing"], Decl(mod1.js, 0, 0))
+
+m1.readonlyProp;
+>m1.readonlyProp : Symbol(m1["readonlyProp"], Decl(mod1.js, 0, 71))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>readonlyProp : Symbol(m1["readonlyProp"], Decl(mod1.js, 0, 71))
+
+m1.rwAccessors;
+>m1.rwAccessors : Symbol(m1["rwAccessors"], Decl(mod1.js, 1, 84))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>rwAccessors : Symbol(m1["rwAccessors"], Decl(mod1.js, 1, 84))
+
+m1.readonlyAccessor;
+>m1.readonlyAccessor : Symbol(m1["readonlyAccessor"], Decl(mod1.js, 2, 97))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>readonlyAccessor : Symbol(m1["readonlyAccessor"], Decl(mod1.js, 2, 97))
+
+m1.setonlyAccessor;
+>m1.setonlyAccessor : Symbol(m1["setonlyAccessor"], Decl(mod1.js, 3, 79))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>setonlyAccessor : Symbol(m1["setonlyAccessor"], Decl(mod1.js, 3, 79))
+
+// allowed assignments
+m1.thing = 10;
+>m1.thing : Symbol(m1["thing"], Decl(mod1.js, 0, 0))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>thing : Symbol(m1["thing"], Decl(mod1.js, 0, 0))
+
+m1.rwAccessors = 11;
+>m1.rwAccessors : Symbol(m1["rwAccessors"], Decl(mod1.js, 1, 84))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>rwAccessors : Symbol(m1["rwAccessors"], Decl(mod1.js, 1, 84))
+
+m1.setonlyAccessor = "yes";
+>m1.setonlyAccessor : Symbol(m1["setonlyAccessor"], Decl(mod1.js, 3, 79))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>setonlyAccessor : Symbol(m1["setonlyAccessor"], Decl(mod1.js, 3, 79))
+
+// disallowed assignments
+m1.readonlyProp = "name";
+>m1.readonlyProp : Symbol(m1["readonlyProp"], Decl(mod1.js, 0, 71))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>readonlyProp : Symbol(m1["readonlyProp"], Decl(mod1.js, 0, 71))
+
+m1.readonlyAccessor = 12;
+>m1.readonlyAccessor : Symbol(m1["readonlyAccessor"], Decl(mod1.js, 2, 97))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>readonlyAccessor : Symbol(m1["readonlyAccessor"], Decl(mod1.js, 2, 97))
+
+m1.thing = "no";
+>m1.thing : Symbol(m1["thing"], Decl(mod1.js, 0, 0))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>thing : Symbol(m1["thing"], Decl(mod1.js, 0, 0))
+
+m1.rwAccessors = "no";
+>m1.rwAccessors : Symbol(m1["rwAccessors"], Decl(mod1.js, 1, 84))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>rwAccessors : Symbol(m1["rwAccessors"], Decl(mod1.js, 1, 84))
+
+m1.setonlyAccessor = 0;
+>m1.setonlyAccessor : Symbol(m1["setonlyAccessor"], Decl(mod1.js, 3, 79))
+>m1 : Symbol(m1, Decl(validator.ts, 0, 12))
+>setonlyAccessor : Symbol(m1["setonlyAccessor"], Decl(mod1.js, 3, 79))
+
+import m2 = require("./mod2");
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+
+m2.thing;
+>m2.thing : Symbol(m2["thing"], Decl(mod2.js, 0, 0))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>thing : Symbol(m2["thing"], Decl(mod2.js, 0, 0))
+
+m2.readonlyProp;
+>m2.readonlyProp : Symbol(m2["readonlyProp"], Decl(mod2.js, 0, 81))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>readonlyProp : Symbol(m2["readonlyProp"], Decl(mod2.js, 0, 81))
+
+m2.rwAccessors;
+>m2.rwAccessors : Symbol(m2["rwAccessors"], Decl(mod2.js, 1, 91))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>rwAccessors : Symbol(m2["rwAccessors"], Decl(mod2.js, 1, 91))
+
+m2.readonlyAccessor;
+>m2.readonlyAccessor : Symbol(m2["readonlyAccessor"], Decl(mod2.js, 2, 104))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>readonlyAccessor : Symbol(m2["readonlyAccessor"], Decl(mod2.js, 2, 104))
+
+m2.setonlyAccessor;
+>m2.setonlyAccessor : Symbol(m2["setonlyAccessor"], Decl(mod2.js, 3, 86))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>setonlyAccessor : Symbol(m2["setonlyAccessor"], Decl(mod2.js, 3, 86))
+
+// allowed assignments
+m2.thing = "ok";
+>m2.thing : Symbol(m2["thing"], Decl(mod2.js, 0, 0))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>thing : Symbol(m2["thing"], Decl(mod2.js, 0, 0))
+
+m2.rwAccessors = 11;
+>m2.rwAccessors : Symbol(m2["rwAccessors"], Decl(mod2.js, 1, 91))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>rwAccessors : Symbol(m2["rwAccessors"], Decl(mod2.js, 1, 91))
+
+m2.setonlyAccessor = "yes";
+>m2.setonlyAccessor : Symbol(m2["setonlyAccessor"], Decl(mod2.js, 3, 86))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>setonlyAccessor : Symbol(m2["setonlyAccessor"], Decl(mod2.js, 3, 86))
+
+// disallowed assignments
+m2.readonlyProp = "name";
+>m2.readonlyProp : Symbol(m2["readonlyProp"], Decl(mod2.js, 0, 81))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>readonlyProp : Symbol(m2["readonlyProp"], Decl(mod2.js, 0, 81))
+
+m2.readonlyAccessor = 12;
+>m2.readonlyAccessor : Symbol(m2["readonlyAccessor"], Decl(mod2.js, 2, 104))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>readonlyAccessor : Symbol(m2["readonlyAccessor"], Decl(mod2.js, 2, 104))
+
+m2.thing = 0;
+>m2.thing : Symbol(m2["thing"], Decl(mod2.js, 0, 0))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>thing : Symbol(m2["thing"], Decl(mod2.js, 0, 0))
+
+m2.rwAccessors = "no";
+>m2.rwAccessors : Symbol(m2["rwAccessors"], Decl(mod2.js, 1, 91))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>rwAccessors : Symbol(m2["rwAccessors"], Decl(mod2.js, 1, 91))
+
+m2.setonlyAccessor = 0;
+>m2.setonlyAccessor : Symbol(m2["setonlyAccessor"], Decl(mod2.js, 3, 86))
+>m2 : Symbol(m2, Decl(validator.ts, 20, 23))
+>setonlyAccessor : Symbol(m2["setonlyAccessor"], Decl(mod2.js, 3, 86))
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+Object.defineProperty(exports, "thing", { value: 42, writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>value : Symbol(value, Decl(mod1.js, 0, 41))
+>writable : Symbol(writable, Decl(mod1.js, 0, 52))
+
+Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>value : Symbol(value, Decl(mod1.js, 1, 48))
+>writable : Symbol(writable, Decl(mod1.js, 1, 64))
+
+Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>get : Symbol(get, Decl(mod1.js, 2, 47))
+>set : Symbol(set, Decl(mod1.js, 2, 71))
+>_ : Symbol(_, Decl(mod1.js, 2, 76))
+
+Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>get : Symbol(get, Decl(mod1.js, 3, 52))
+
+Object.defineProperty(exports, "setonlyAccessor", {
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+
+    /** @param {string} str */
+    set(str) {
+>set : Symbol(set, Decl(mod1.js, 4, 51))
+>str : Symbol(str, Decl(mod1.js, 6, 8))
+
+        this.rwAccessors = Number(str) 
+>rwAccessors : Symbol(rwAccessors, Decl(mod1.js, 6, 14))
+>Number : Symbol(Number, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>str : Symbol(str, Decl(mod1.js, 6, 8))
+    }
+});
+
+=== tests/cases/conformance/jsdoc/mod2.js ===
+Object.defineProperty(module.exports, "thing", { value: "yes", writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>module.exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>module : Symbol(module, Decl(mod2.js, 0, 22))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>value : Symbol(value, Decl(mod2.js, 0, 48))
+>writable : Symbol(writable, Decl(mod2.js, 0, 62))
+
+Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>module.exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>module : Symbol(module, Decl(mod2.js, 0, 22))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>value : Symbol(value, Decl(mod2.js, 1, 55))
+>writable : Symbol(writable, Decl(mod2.js, 1, 71))
+
+Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>module.exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>module : Symbol(module, Decl(mod2.js, 0, 22))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>get : Symbol(get, Decl(mod2.js, 2, 54))
+>set : Symbol(set, Decl(mod2.js, 2, 78))
+>_ : Symbol(_, Decl(mod2.js, 2, 83))
+
+Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>module.exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>module : Symbol(module, Decl(mod2.js, 0, 22))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>get : Symbol(get, Decl(mod2.js, 3, 59))
+
+Object.defineProperty(module.exports, "setonlyAccessor", {
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>module.exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>module : Symbol(module, Decl(mod2.js, 0, 22))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+
+    /** @param {string} str */
+    set(str) {
+>set : Symbol(set, Decl(mod2.js, 4, 58))
+>str : Symbol(str, Decl(mod2.js, 6, 8))
+
+        this.rwAccessors = Number(str) 
+>rwAccessors : Symbol(rwAccessors, Decl(mod2.js, 6, 14))
+>Number : Symbol(Number, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>str : Symbol(str, Decl(mod2.js, 6, 8))
+    }
+});
+
+=== tests/cases/conformance/jsdoc/index.js ===
+/**
+ * @type {number}
+ */
+const q = require("./mod1").thing;
+>q : Symbol(q, Decl(index.js, 3, 5))
+>require("./mod1").thing : Symbol("thing", Decl(mod1.js, 0, 0))
+>require : Symbol(require)
+>"./mod1" : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>thing : Symbol("thing", Decl(mod1.js, 0, 0))
+
+/**
+ * @type {string}
+ */
+const u = require("./mod2").thing;
+>u : Symbol(u, Decl(index.js, 8, 5))
+>require("./mod2").thing : Symbol("thing", Decl(mod2.js, 0, 0))
+>require : Symbol(require)
+>"./mod2" : Symbol("tests/cases/conformance/jsdoc/mod2", Decl(mod2.js, 0, 0))
+>thing : Symbol("thing", Decl(mod2.js, 0, 0))
+
diff --git a/tests/baselines/reference/checkExportsObjectAssignProperty.types b/tests/baselines/reference/checkExportsObjectAssignProperty.types
new file mode 100644
index 0000000000000..847ac720d75c1
--- /dev/null
+++ b/tests/baselines/reference/checkExportsObjectAssignProperty.types
@@ -0,0 +1,360 @@
+=== tests/cases/conformance/jsdoc/validator.ts ===
+import "./";
+
+import m1 = require("./mod1");
+>m1 : typeof m1
+
+m1.thing;
+>m1.thing : number
+>m1 : typeof m1
+>thing : number
+
+m1.readonlyProp;
+>m1.readonlyProp : string
+>m1 : typeof m1
+>readonlyProp : string
+
+m1.rwAccessors;
+>m1.rwAccessors : number
+>m1 : typeof m1
+>rwAccessors : number
+
+m1.readonlyAccessor;
+>m1.readonlyAccessor : number
+>m1 : typeof m1
+>readonlyAccessor : number
+
+m1.setonlyAccessor;
+>m1.setonlyAccessor : string
+>m1 : typeof m1
+>setonlyAccessor : string
+
+// allowed assignments
+m1.thing = 10;
+>m1.thing = 10 : 10
+>m1.thing : number
+>m1 : typeof m1
+>thing : number
+>10 : 10
+
+m1.rwAccessors = 11;
+>m1.rwAccessors = 11 : 11
+>m1.rwAccessors : number
+>m1 : typeof m1
+>rwAccessors : number
+>11 : 11
+
+m1.setonlyAccessor = "yes";
+>m1.setonlyAccessor = "yes" : "yes"
+>m1.setonlyAccessor : string
+>m1 : typeof m1
+>setonlyAccessor : string
+>"yes" : "yes"
+
+// disallowed assignments
+m1.readonlyProp = "name";
+>m1.readonlyProp = "name" : "name"
+>m1.readonlyProp : any
+>m1 : typeof m1
+>readonlyProp : any
+>"name" : "name"
+
+m1.readonlyAccessor = 12;
+>m1.readonlyAccessor = 12 : 12
+>m1.readonlyAccessor : any
+>m1 : typeof m1
+>readonlyAccessor : any
+>12 : 12
+
+m1.thing = "no";
+>m1.thing = "no" : "no"
+>m1.thing : number
+>m1 : typeof m1
+>thing : number
+>"no" : "no"
+
+m1.rwAccessors = "no";
+>m1.rwAccessors = "no" : "no"
+>m1.rwAccessors : number
+>m1 : typeof m1
+>rwAccessors : number
+>"no" : "no"
+
+m1.setonlyAccessor = 0;
+>m1.setonlyAccessor = 0 : 0
+>m1.setonlyAccessor : string
+>m1 : typeof m1
+>setonlyAccessor : string
+>0 : 0
+
+import m2 = require("./mod2");
+>m2 : typeof m2
+
+m2.thing;
+>m2.thing : string
+>m2 : typeof m2
+>thing : string
+
+m2.readonlyProp;
+>m2.readonlyProp : string
+>m2 : typeof m2
+>readonlyProp : string
+
+m2.rwAccessors;
+>m2.rwAccessors : number
+>m2 : typeof m2
+>rwAccessors : number
+
+m2.readonlyAccessor;
+>m2.readonlyAccessor : number
+>m2 : typeof m2
+>readonlyAccessor : number
+
+m2.setonlyAccessor;
+>m2.setonlyAccessor : string
+>m2 : typeof m2
+>setonlyAccessor : string
+
+// allowed assignments
+m2.thing = "ok";
+>m2.thing = "ok" : "ok"
+>m2.thing : string
+>m2 : typeof m2
+>thing : string
+>"ok" : "ok"
+
+m2.rwAccessors = 11;
+>m2.rwAccessors = 11 : 11
+>m2.rwAccessors : number
+>m2 : typeof m2
+>rwAccessors : number
+>11 : 11
+
+m2.setonlyAccessor = "yes";
+>m2.setonlyAccessor = "yes" : "yes"
+>m2.setonlyAccessor : string
+>m2 : typeof m2
+>setonlyAccessor : string
+>"yes" : "yes"
+
+// disallowed assignments
+m2.readonlyProp = "name";
+>m2.readonlyProp = "name" : "name"
+>m2.readonlyProp : any
+>m2 : typeof m2
+>readonlyProp : any
+>"name" : "name"
+
+m2.readonlyAccessor = 12;
+>m2.readonlyAccessor = 12 : 12
+>m2.readonlyAccessor : any
+>m2 : typeof m2
+>readonlyAccessor : any
+>12 : 12
+
+m2.thing = 0;
+>m2.thing = 0 : 0
+>m2.thing : string
+>m2 : typeof m2
+>thing : string
+>0 : 0
+
+m2.rwAccessors = "no";
+>m2.rwAccessors = "no" : "no"
+>m2.rwAccessors : number
+>m2 : typeof m2
+>rwAccessors : number
+>"no" : "no"
+
+m2.setonlyAccessor = 0;
+>m2.setonlyAccessor = 0 : 0
+>m2.setonlyAccessor : string
+>m2 : typeof m2
+>setonlyAccessor : string
+>0 : 0
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+Object.defineProperty(exports, "thing", { value: 42, writable: true });
+>Object.defineProperty(exports, "thing", { value: 42, writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"thing" : "thing"
+>{ value: 42, writable: true } : { value: number; writable: true; }
+>value : number
+>42 : 42
+>writable : true
+>true : true
+
+Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false });
+>Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"readonlyProp" : "readonlyProp"
+>{ value: "Smith", writable: false } : { value: string; writable: false; }
+>value : string
+>"Smith" : "Smith"
+>writable : false
+>false : false
+
+Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"rwAccessors" : "rwAccessors"
+>{ get() { return 98122 }, set(_) { /*ignore*/ } } : { get(): number; set(_: any): void; }
+>get : () => number
+>98122 : 98122
+>set : (_: any) => void
+>_ : any
+
+Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } });
+>Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"readonlyAccessor" : "readonlyAccessor"
+>{ get() { return 21.75 } } : { get(): number; }
+>get : () => number
+>21.75 : 21.75
+
+Object.defineProperty(exports, "setonlyAccessor", {
+>Object.defineProperty(exports, "setonlyAccessor", {    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }}) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"setonlyAccessor" : "setonlyAccessor"
+>{    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }} : { set(str: string): void; }
+
+    /** @param {string} str */
+    set(str) {
+>set : (str: string) => void
+>str : string
+
+        this.rwAccessors = Number(str) 
+>this.rwAccessors = Number(str) : number
+>this.rwAccessors : any
+>this : any
+>rwAccessors : any
+>Number(str) : number
+>Number : NumberConstructor
+>str : string
+    }
+});
+
+=== tests/cases/conformance/jsdoc/mod2.js ===
+Object.defineProperty(module.exports, "thing", { value: "yes", writable: true });
+>Object.defineProperty(module.exports, "thing", { value: "yes", writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>module.exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>module : { "tests/cases/conformance/jsdoc/mod2": typeof import("tests/cases/conformance/jsdoc/mod2"); }
+>exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>"thing" : "thing"
+>{ value: "yes", writable: true } : { value: string; writable: true; }
+>value : string
+>"yes" : "yes"
+>writable : true
+>true : true
+
+Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false });
+>Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>module.exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>module : { "tests/cases/conformance/jsdoc/mod2": typeof import("tests/cases/conformance/jsdoc/mod2"); }
+>exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>"readonlyProp" : "readonlyProp"
+>{ value: "Smith", writable: false } : { value: string; writable: false; }
+>value : string
+>"Smith" : "Smith"
+>writable : false
+>false : false
+
+Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>module.exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>module : { "tests/cases/conformance/jsdoc/mod2": typeof import("tests/cases/conformance/jsdoc/mod2"); }
+>exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>"rwAccessors" : "rwAccessors"
+>{ get() { return 98122 }, set(_) { /*ignore*/ } } : { get(): number; set(_: any): void; }
+>get : () => number
+>98122 : 98122
+>set : (_: any) => void
+>_ : any
+
+Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } });
+>Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>module.exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>module : { "tests/cases/conformance/jsdoc/mod2": typeof import("tests/cases/conformance/jsdoc/mod2"); }
+>exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>"readonlyAccessor" : "readonlyAccessor"
+>{ get() { return 21.75 } } : { get(): number; }
+>get : () => number
+>21.75 : 21.75
+
+Object.defineProperty(module.exports, "setonlyAccessor", {
+>Object.defineProperty(module.exports, "setonlyAccessor", {    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }}) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>module.exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>module : { "tests/cases/conformance/jsdoc/mod2": typeof import("tests/cases/conformance/jsdoc/mod2"); }
+>exports : typeof import("tests/cases/conformance/jsdoc/mod2")
+>"setonlyAccessor" : "setonlyAccessor"
+>{    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)     }} : { set(str: string): void; }
+
+    /** @param {string} str */
+    set(str) {
+>set : (str: string) => void
+>str : string
+
+        this.rwAccessors = Number(str) 
+>this.rwAccessors = Number(str) : number
+>this.rwAccessors : any
+>this : any
+>rwAccessors : any
+>Number(str) : number
+>Number : NumberConstructor
+>str : string
+    }
+});
+
+=== tests/cases/conformance/jsdoc/index.js ===
+/**
+ * @type {number}
+ */
+const q = require("./mod1").thing;
+>q : number
+>require("./mod1").thing : number
+>require("./mod1") : typeof import("tests/cases/conformance/jsdoc/mod1")
+>require : any
+>"./mod1" : "./mod1"
+>thing : number
+
+/**
+ * @type {string}
+ */
+const u = require("./mod2").thing;
+>u : string
+>require("./mod2").thing : string
+>require("./mod2") : typeof import("tests/cases/conformance/jsdoc/mod2")
+>require : any
+>"./mod2" : "./mod2"
+>thing : string
+
diff --git a/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.errors.txt b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.errors.txt
new file mode 100644
index 0000000000000..c2621a71b9915
--- /dev/null
+++ b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.errors.txt
@@ -0,0 +1,66 @@
+tests/cases/conformance/jsdoc/validator.ts(19,4): error TS2540: Cannot assign to 'readonlyProp' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validator.ts(20,4): error TS2540: Cannot assign to 'readonlyAccessor' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validator.ts(21,1): error TS2322: Type '"no"' is not assignable to type 'number'.
+tests/cases/conformance/jsdoc/validator.ts(22,1): error TS2322: Type '"no"' is not assignable to type 'number'.
+tests/cases/conformance/jsdoc/validator.ts(23,1): error TS2322: Type '0' is not assignable to type 'string'.
+
+
+==== tests/cases/conformance/jsdoc/validator.ts (5 errors) ====
+    import "./";
+    
+    import Person = require("./mod1");
+    
+    const m1 = new Person("Name")
+    
+    m1.thing;
+    m1.readonlyProp;
+    m1.rwAccessors;
+    m1.readonlyAccessor;
+    m1.setonlyAccessor;
+    
+    // allowed assignments
+    m1.thing = 10;
+    m1.rwAccessors = 11;
+    m1.setonlyAccessor = "yes";
+    
+    // disallowed assignments
+    m1.readonlyProp = "name";
+       ~~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'readonlyProp' because it is a constant or a read-only property.
+    m1.readonlyAccessor = 12;
+       ~~~~~~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'readonlyAccessor' because it is a constant or a read-only property.
+    m1.thing = "no";
+    ~~~~~~~~
+!!! error TS2322: Type '"no"' is not assignable to type 'number'.
+    m1.rwAccessors = "no";
+    ~~~~~~~~~~~~~~
+!!! error TS2322: Type '"no"' is not assignable to type 'number'.
+    m1.setonlyAccessor = 0;
+    ~~~~~~~~~~~~~~~~~~
+!!! error TS2322: Type '0' is not assignable to type 'string'.
+    
+    
+==== tests/cases/conformance/jsdoc/mod1.js (0 errors) ====
+    /**
+     * @constructor
+     * @param {string} name
+     */
+    function Person(name) {
+        this.name = name;
+    }
+    Person.prototype.describe = function () {
+        return "Person called " + this.name;
+    };
+    Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true });
+    Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false });
+    Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+    Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } });
+    Object.defineProperty(Person.prototype, "setonlyAccessor", {
+        /** @param {string} str */
+        set(str) {
+            this.rwAccessors = Number(str)
+        }
+    });
+    module.exports = Person;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.symbols b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.symbols
new file mode 100644
index 0000000000000..9f04a3600cce9
--- /dev/null
+++ b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.symbols
@@ -0,0 +1,172 @@
+=== tests/cases/conformance/jsdoc/validator.ts ===
+import "./";
+
+import Person = require("./mod1");
+>Person : Symbol(Person, Decl(validator.ts, 0, 12))
+
+const m1 = new Person("Name")
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>Person : Symbol(Person, Decl(validator.ts, 0, 12))
+
+m1.thing;
+>m1.thing : Symbol(Person["thing"], Decl(mod1.js, 9, 2))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>thing : Symbol(Person["thing"], Decl(mod1.js, 9, 2))
+
+m1.readonlyProp;
+>m1.readonlyProp : Symbol(Person["readonlyProp"], Decl(mod1.js, 10, 80))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>readonlyProp : Symbol(Person["readonlyProp"], Decl(mod1.js, 10, 80))
+
+m1.rwAccessors;
+>m1.rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+
+m1.readonlyAccessor;
+>m1.readonlyAccessor : Symbol(Person["readonlyAccessor"], Decl(mod1.js, 12, 106))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>readonlyAccessor : Symbol(Person["readonlyAccessor"], Decl(mod1.js, 12, 106))
+
+m1.setonlyAccessor;
+>m1.setonlyAccessor : Symbol(Person["setonlyAccessor"], Decl(mod1.js, 13, 88))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>setonlyAccessor : Symbol(Person["setonlyAccessor"], Decl(mod1.js, 13, 88))
+
+// allowed assignments
+m1.thing = 10;
+>m1.thing : Symbol(Person["thing"], Decl(mod1.js, 9, 2))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>thing : Symbol(Person["thing"], Decl(mod1.js, 9, 2))
+
+m1.rwAccessors = 11;
+>m1.rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+
+m1.setonlyAccessor = "yes";
+>m1.setonlyAccessor : Symbol(Person["setonlyAccessor"], Decl(mod1.js, 13, 88))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>setonlyAccessor : Symbol(Person["setonlyAccessor"], Decl(mod1.js, 13, 88))
+
+// disallowed assignments
+m1.readonlyProp = "name";
+>m1.readonlyProp : Symbol(Person["readonlyProp"], Decl(mod1.js, 10, 80))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>readonlyProp : Symbol(Person["readonlyProp"], Decl(mod1.js, 10, 80))
+
+m1.readonlyAccessor = 12;
+>m1.readonlyAccessor : Symbol(Person["readonlyAccessor"], Decl(mod1.js, 12, 106))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>readonlyAccessor : Symbol(Person["readonlyAccessor"], Decl(mod1.js, 12, 106))
+
+m1.thing = "no";
+>m1.thing : Symbol(Person["thing"], Decl(mod1.js, 9, 2))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>thing : Symbol(Person["thing"], Decl(mod1.js, 9, 2))
+
+m1.rwAccessors = "no";
+>m1.rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+
+m1.setonlyAccessor = 0;
+>m1.setonlyAccessor : Symbol(Person["setonlyAccessor"], Decl(mod1.js, 13, 88))
+>m1 : Symbol(m1, Decl(validator.ts, 4, 5))
+>setonlyAccessor : Symbol(Person["setonlyAccessor"], Decl(mod1.js, 13, 88))
+
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+/**
+ * @constructor
+ * @param {string} name
+ */
+function Person(name) {
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>name : Symbol(name, Decl(mod1.js, 4, 16))
+
+    this.name = name;
+>this.name : Symbol(Person.name, Decl(mod1.js, 4, 23))
+>this : Symbol(Person, Decl(mod1.js, 0, 0))
+>name : Symbol(Person.name, Decl(mod1.js, 4, 23))
+>name : Symbol(name, Decl(mod1.js, 4, 16))
+}
+Person.prototype.describe = function () {
+>Person.prototype : Symbol(Person.describe, Decl(mod1.js, 6, 1))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>describe : Symbol(Person.describe, Decl(mod1.js, 6, 1))
+
+    return "Person called " + this.name;
+>this.name : Symbol(Person.name, Decl(mod1.js, 4, 23))
+>this : Symbol(Person, Decl(mod1.js, 0, 0))
+>name : Symbol(Person.name, Decl(mod1.js, 4, 23))
+
+};
+Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Person.prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>value : Symbol(value, Decl(mod1.js, 10, 50))
+>writable : Symbol(writable, Decl(mod1.js, 10, 61))
+
+Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Person.prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>value : Symbol(value, Decl(mod1.js, 11, 57))
+>writable : Symbol(writable, Decl(mod1.js, 11, 73))
+
+Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Person.prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>get : Symbol(get, Decl(mod1.js, 12, 56))
+>set : Symbol(set, Decl(mod1.js, 12, 80))
+>_ : Symbol(_, Decl(mod1.js, 12, 85))
+
+Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Person.prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>get : Symbol(get, Decl(mod1.js, 13, 61))
+
+Object.defineProperty(Person.prototype, "setonlyAccessor", {
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Person.prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.es5.d.ts, --, --))
+
+    /** @param {string} str */
+    set(str) {
+>set : Symbol(set, Decl(mod1.js, 14, 60))
+>str : Symbol(str, Decl(mod1.js, 16, 8))
+
+        this.rwAccessors = Number(str)
+>this.rwAccessors : Symbol(Person["rwAccessors"], Decl(mod1.js, 11, 93))
+>this : Symbol(Person, Decl(mod1.js, 0, 0))
+>rwAccessors : Symbol(rwAccessors, Decl(mod1.js, 16, 14))
+>Number : Symbol(Number, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>str : Symbol(str, Decl(mod1.js, 16, 8))
+    }
+});
+module.exports = Person;
+>module.exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>module : Symbol(export=, Decl(mod1.js, 19, 3))
+>exports : Symbol(export=, Decl(mod1.js, 19, 3))
+>Person : Symbol(Person, Decl(mod1.js, 0, 0))
+
diff --git a/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types
new file mode 100644
index 0000000000000..662c578701f56
--- /dev/null
+++ b/tests/baselines/reference/checkExportsObjectAssignPrototypeProperty.types
@@ -0,0 +1,220 @@
+=== tests/cases/conformance/jsdoc/validator.ts ===
+import "./";
+
+import Person = require("./mod1");
+>Person : typeof Person
+
+const m1 = new Person("Name")
+>m1 : Person
+>new Person("Name") : Person
+>Person : typeof Person
+>"Name" : "Name"
+
+m1.thing;
+>m1.thing : number
+>m1 : Person
+>thing : number
+
+m1.readonlyProp;
+>m1.readonlyProp : string
+>m1 : Person
+>readonlyProp : string
+
+m1.rwAccessors;
+>m1.rwAccessors : number
+>m1 : Person
+>rwAccessors : number
+
+m1.readonlyAccessor;
+>m1.readonlyAccessor : number
+>m1 : Person
+>readonlyAccessor : number
+
+m1.setonlyAccessor;
+>m1.setonlyAccessor : string
+>m1 : Person
+>setonlyAccessor : string
+
+// allowed assignments
+m1.thing = 10;
+>m1.thing = 10 : 10
+>m1.thing : number
+>m1 : Person
+>thing : number
+>10 : 10
+
+m1.rwAccessors = 11;
+>m1.rwAccessors = 11 : 11
+>m1.rwAccessors : number
+>m1 : Person
+>rwAccessors : number
+>11 : 11
+
+m1.setonlyAccessor = "yes";
+>m1.setonlyAccessor = "yes" : "yes"
+>m1.setonlyAccessor : string
+>m1 : Person
+>setonlyAccessor : string
+>"yes" : "yes"
+
+// disallowed assignments
+m1.readonlyProp = "name";
+>m1.readonlyProp = "name" : "name"
+>m1.readonlyProp : any
+>m1 : Person
+>readonlyProp : any
+>"name" : "name"
+
+m1.readonlyAccessor = 12;
+>m1.readonlyAccessor = 12 : 12
+>m1.readonlyAccessor : any
+>m1 : Person
+>readonlyAccessor : any
+>12 : 12
+
+m1.thing = "no";
+>m1.thing = "no" : "no"
+>m1.thing : number
+>m1 : Person
+>thing : number
+>"no" : "no"
+
+m1.rwAccessors = "no";
+>m1.rwAccessors = "no" : "no"
+>m1.rwAccessors : number
+>m1 : Person
+>rwAccessors : number
+>"no" : "no"
+
+m1.setonlyAccessor = 0;
+>m1.setonlyAccessor = 0 : 0
+>m1.setonlyAccessor : string
+>m1 : Person
+>setonlyAccessor : string
+>0 : 0
+
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+/**
+ * @constructor
+ * @param {string} name
+ */
+function Person(name) {
+>Person : typeof Person
+>name : string
+
+    this.name = name;
+>this.name = name : string
+>this.name : string
+>this : Person
+>name : string
+>name : string
+}
+Person.prototype.describe = function () {
+>Person.prototype.describe = function () {    return "Person called " + this.name;} : () => string
+>Person.prototype.describe : any
+>Person.prototype : any
+>Person : typeof Person
+>prototype : any
+>describe : any
+>function () {    return "Person called " + this.name;} : () => string
+
+    return "Person called " + this.name;
+>"Person called " + this.name : string
+>"Person called " : "Person called "
+>this.name : string
+>this : Person
+>name : string
+
+};
+Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true });
+>Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Person.prototype : any
+>Person : typeof Person
+>prototype : any
+>"thing" : "thing"
+>{ value: 42, writable: true } : { value: number; writable: true; }
+>value : number
+>42 : 42
+>writable : true
+>true : true
+
+Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false });
+>Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Person.prototype : any
+>Person : typeof Person
+>prototype : any
+>"readonlyProp" : "readonlyProp"
+>{ value: "Smith", writable: false } : { value: string; writable: false; }
+>value : string
+>"Smith" : "Smith"
+>writable : false
+>false : false
+
+Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Person.prototype : any
+>Person : typeof Person
+>prototype : any
+>"rwAccessors" : "rwAccessors"
+>{ get() { return 98122 }, set(_) { /*ignore*/ } } : { get(): number; set(_: any): void; }
+>get : () => number
+>98122 : 98122
+>set : (_: any) => void
+>_ : any
+
+Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } });
+>Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Person.prototype : any
+>Person : typeof Person
+>prototype : any
+>"readonlyAccessor" : "readonlyAccessor"
+>{ get() { return 21.75 } } : { get(): number; }
+>get : () => number
+>21.75 : 21.75
+
+Object.defineProperty(Person.prototype, "setonlyAccessor", {
+>Object.defineProperty(Person.prototype, "setonlyAccessor", {    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)    }}) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Person.prototype : any
+>Person : typeof Person
+>prototype : any
+>"setonlyAccessor" : "setonlyAccessor"
+>{    /** @param {string} str */    set(str) {        this.rwAccessors = Number(str)    }} : { set(str: string): void; }
+
+    /** @param {string} str */
+    set(str) {
+>set : (str: string) => void
+>str : string
+
+        this.rwAccessors = Number(str)
+>this.rwAccessors = Number(str) : number
+>this.rwAccessors : number
+>this : Person
+>rwAccessors : number
+>Number(str) : number
+>Number : NumberConstructor
+>str : string
+    }
+});
+module.exports = Person;
+>module.exports = Person : typeof Person
+>module.exports : typeof Person
+>module : { "tests/cases/conformance/jsdoc/mod1": typeof Person; }
+>exports : typeof Person
+>Person : typeof Person
+
diff --git a/tests/baselines/reference/checkObjectDefineProperty.errors.txt b/tests/baselines/reference/checkObjectDefineProperty.errors.txt
new file mode 100644
index 0000000000000..b587955ef2f81
--- /dev/null
+++ b/tests/baselines/reference/checkObjectDefineProperty.errors.txt
@@ -0,0 +1,79 @@
+tests/cases/conformance/jsdoc/validate.ts(14,3): error TS2540: Cannot assign to 'lastName' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validate.ts(15,3): error TS2540: Cannot assign to 'houseNumber' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/validate.ts(16,1): error TS2322: Type '12' is not assignable to type 'string'.
+tests/cases/conformance/jsdoc/validate.ts(17,3): error TS2540: Cannot assign to 'middleInit' because it is a constant or a read-only property.
+
+
+==== tests/cases/conformance/jsdoc/validate.ts (4 errors) ====
+    // Validate in TS as simple validations would usually be interpreted as more special assignments
+    import x = require("./");
+    x.name;
+    x.middleInit;
+    x.lastName;
+    x.zip;
+    x.houseNumber;
+    x.zipStr;
+    
+    x.name = "Another";
+    x.zip = 98123;
+    x.zipStr = "OK";
+    
+    x.lastName = "should fail";
+      ~~~~~~~~
+!!! error TS2540: Cannot assign to 'lastName' because it is a constant or a read-only property.
+    x.houseNumber = 12; // should also fail
+      ~~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'houseNumber' because it is a constant or a read-only property.
+    x.zipStr = 12; // should fail
+    ~~~~~~~~
+!!! error TS2322: Type '12' is not assignable to type 'string'.
+    x.middleInit = "R"; // should also fail
+      ~~~~~~~~~~
+!!! error TS2540: Cannot assign to 'middleInit' because it is a constant or a read-only property.
+    
+==== tests/cases/conformance/jsdoc/index.js (0 errors) ====
+    const x = {};
+    Object.defineProperty(x, "name", { value: "Charles", writable: true });
+    Object.defineProperty(x, "middleInit", { value: "H" });
+    Object.defineProperty(x, "lastName", { value: "Smith", writable: false });
+    Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } });
+    Object.defineProperty(x, "houseNumber", { get() { return 21.75 } });
+    Object.defineProperty(x, "zipStr", {
+        /** @param {string} str */
+        set(str) {
+            this.zip = Number(str) 
+        }
+    });
+    
+    /**
+     * @param {{name: string}} named
+     */
+    function takeName(named) { return named.name; }
+    
+    takeName(x);
+    /**
+     * @type {number}
+     */
+    var a = x.zip;
+    
+    /**
+     * @type {number}
+     */
+    var b = x.houseNumber;
+    
+    const returnExemplar = () => x;
+    const needsExemplar = (_ = x) => void 0;
+    
+    const expected = /** @type {{name: string, readonly middleInit: string, readonly lastName: string, zip: number, readonly houseNumber: number, zipStr: string}} */(/** @type {*} */(null));
+    
+    /**
+     * 
+     * @param {typeof returnExemplar} a 
+     * @param {typeof needsExemplar} b 
+     */
+    function match(a, b) {}
+    
+    match(() => expected, (x = expected) => void 0);
+    
+    module.exports = x;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/checkObjectDefineProperty.symbols b/tests/baselines/reference/checkObjectDefineProperty.symbols
new file mode 100644
index 0000000000000..d3eea1a0a7461
--- /dev/null
+++ b/tests/baselines/reference/checkObjectDefineProperty.symbols
@@ -0,0 +1,197 @@
+=== tests/cases/conformance/jsdoc/validate.ts ===
+// Validate in TS as simple validations would usually be interpreted as more special assignments
+import x = require("./");
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+
+x.name;
+>x.name : Symbol(x["name"], Decl(index.js, 0, 13))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>name : Symbol(x["name"], Decl(index.js, 0, 13))
+
+x.middleInit;
+>x.middleInit : Symbol(x["middleInit"], Decl(index.js, 1, 71))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>middleInit : Symbol(x["middleInit"], Decl(index.js, 1, 71))
+
+x.lastName;
+>x.lastName : Symbol(x["lastName"], Decl(index.js, 2, 55))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>lastName : Symbol(x["lastName"], Decl(index.js, 2, 55))
+
+x.zip;
+>x.zip : Symbol(x["zip"], Decl(index.js, 3, 74))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>zip : Symbol(x["zip"], Decl(index.js, 3, 74))
+
+x.houseNumber;
+>x.houseNumber : Symbol(x["houseNumber"], Decl(index.js, 4, 83))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>houseNumber : Symbol(x["houseNumber"], Decl(index.js, 4, 83))
+
+x.zipStr;
+>x.zipStr : Symbol(x["zipStr"], Decl(index.js, 5, 68))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>zipStr : Symbol(x["zipStr"], Decl(index.js, 5, 68))
+
+x.name = "Another";
+>x.name : Symbol(x["name"], Decl(index.js, 0, 13))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>name : Symbol(x["name"], Decl(index.js, 0, 13))
+
+x.zip = 98123;
+>x.zip : Symbol(x["zip"], Decl(index.js, 3, 74))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>zip : Symbol(x["zip"], Decl(index.js, 3, 74))
+
+x.zipStr = "OK";
+>x.zipStr : Symbol(x["zipStr"], Decl(index.js, 5, 68))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>zipStr : Symbol(x["zipStr"], Decl(index.js, 5, 68))
+
+x.lastName = "should fail";
+>x.lastName : Symbol(x["lastName"], Decl(index.js, 2, 55))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>lastName : Symbol(x["lastName"], Decl(index.js, 2, 55))
+
+x.houseNumber = 12; // should also fail
+>x.houseNumber : Symbol(x["houseNumber"], Decl(index.js, 4, 83))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>houseNumber : Symbol(x["houseNumber"], Decl(index.js, 4, 83))
+
+x.zipStr = 12; // should fail
+>x.zipStr : Symbol(x["zipStr"], Decl(index.js, 5, 68))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>zipStr : Symbol(x["zipStr"], Decl(index.js, 5, 68))
+
+x.middleInit = "R"; // should also fail
+>x.middleInit : Symbol(x["middleInit"], Decl(index.js, 1, 71))
+>x : Symbol(x, Decl(validate.ts, 0, 0))
+>middleInit : Symbol(x["middleInit"], Decl(index.js, 1, 71))
+
+=== tests/cases/conformance/jsdoc/index.js ===
+const x = {};
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+
+Object.defineProperty(x, "name", { value: "Charles", writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>value : Symbol(value, Decl(index.js, 1, 34))
+>writable : Symbol(writable, Decl(index.js, 1, 52))
+
+Object.defineProperty(x, "middleInit", { value: "H" });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>value : Symbol(value, Decl(index.js, 2, 40))
+
+Object.defineProperty(x, "lastName", { value: "Smith", writable: false });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>value : Symbol(value, Decl(index.js, 3, 38))
+>writable : Symbol(writable, Decl(index.js, 3, 54))
+
+Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>get : Symbol(get, Decl(index.js, 4, 33))
+>set : Symbol(set, Decl(index.js, 4, 57))
+>_ : Symbol(_, Decl(index.js, 4, 62))
+
+Object.defineProperty(x, "houseNumber", { get() { return 21.75 } });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>get : Symbol(get, Decl(index.js, 5, 41))
+
+Object.defineProperty(x, "zipStr", {
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+
+    /** @param {string} str */
+    set(str) {
+>set : Symbol(set, Decl(index.js, 6, 36))
+>str : Symbol(str, Decl(index.js, 8, 8))
+
+        this.zip = Number(str) 
+>zip : Symbol(zip, Decl(index.js, 8, 14))
+>Number : Symbol(Number, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>str : Symbol(str, Decl(index.js, 8, 8))
+    }
+});
+
+/**
+ * @param {{name: string}} named
+ */
+function takeName(named) { return named.name; }
+>takeName : Symbol(takeName, Decl(index.js, 11, 3))
+>named : Symbol(named, Decl(index.js, 16, 18))
+>named.name : Symbol(name, Decl(index.js, 14, 12))
+>named : Symbol(named, Decl(index.js, 16, 18))
+>name : Symbol(name, Decl(index.js, 14, 12))
+
+takeName(x);
+>takeName : Symbol(takeName, Decl(index.js, 11, 3))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+
+/**
+ * @type {number}
+ */
+var a = x.zip;
+>a : Symbol(a, Decl(index.js, 22, 3))
+>x.zip : Symbol(x["zip"], Decl(index.js, 3, 74))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>zip : Symbol(x["zip"], Decl(index.js, 3, 74))
+
+/**
+ * @type {number}
+ */
+var b = x.houseNumber;
+>b : Symbol(b, Decl(index.js, 27, 3))
+>x.houseNumber : Symbol(x["houseNumber"], Decl(index.js, 4, 83))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+>houseNumber : Symbol(x["houseNumber"], Decl(index.js, 4, 83))
+
+const returnExemplar = () => x;
+>returnExemplar : Symbol(returnExemplar, Decl(index.js, 29, 5))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+
+const needsExemplar = (_ = x) => void 0;
+>needsExemplar : Symbol(needsExemplar, Decl(index.js, 30, 5))
+>_ : Symbol(_, Decl(index.js, 30, 23))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+
+const expected = /** @type {{name: string, readonly middleInit: string, readonly lastName: string, zip: number, readonly houseNumber: number, zipStr: string}} */(/** @type {*} */(null));
+>expected : Symbol(expected, Decl(index.js, 32, 5))
+
+/**
+ * 
+ * @param {typeof returnExemplar} a 
+ * @param {typeof needsExemplar} b 
+ */
+function match(a, b) {}
+>match : Symbol(match, Decl(index.js, 32, 186))
+>a : Symbol(a, Decl(index.js, 39, 15))
+>b : Symbol(b, Decl(index.js, 39, 17))
+
+match(() => expected, (x = expected) => void 0);
+>match : Symbol(match, Decl(index.js, 32, 186))
+>expected : Symbol(expected, Decl(index.js, 32, 5))
+>x : Symbol(x, Decl(index.js, 41, 23))
+>expected : Symbol(expected, Decl(index.js, 32, 5))
+
+module.exports = x;
+>module.exports : Symbol("tests/cases/conformance/jsdoc/index", Decl(index.js, 0, 0))
+>module : Symbol(export=, Decl(index.js, 41, 48))
+>exports : Symbol(export=, Decl(index.js, 41, 48))
+>x : Symbol(x, Decl(index.js, 0, 5), Decl(index.js, 1, 22))
+
diff --git a/tests/baselines/reference/checkObjectDefineProperty.types b/tests/baselines/reference/checkObjectDefineProperty.types
new file mode 100644
index 0000000000000..88a1e682dfc9e
--- /dev/null
+++ b/tests/baselines/reference/checkObjectDefineProperty.types
@@ -0,0 +1,255 @@
+=== tests/cases/conformance/jsdoc/validate.ts ===
+// Validate in TS as simple validations would usually be interpreted as more special assignments
+import x = require("./");
+>x : typeof x
+
+x.name;
+>x.name : string
+>x : typeof x
+>name : string
+
+x.middleInit;
+>x.middleInit : string
+>x : typeof x
+>middleInit : string
+
+x.lastName;
+>x.lastName : string
+>x : typeof x
+>lastName : string
+
+x.zip;
+>x.zip : number
+>x : typeof x
+>zip : number
+
+x.houseNumber;
+>x.houseNumber : number
+>x : typeof x
+>houseNumber : number
+
+x.zipStr;
+>x.zipStr : string
+>x : typeof x
+>zipStr : string
+
+x.name = "Another";
+>x.name = "Another" : "Another"
+>x.name : string
+>x : typeof x
+>name : string
+>"Another" : "Another"
+
+x.zip = 98123;
+>x.zip = 98123 : 98123
+>x.zip : number
+>x : typeof x
+>zip : number
+>98123 : 98123
+
+x.zipStr = "OK";
+>x.zipStr = "OK" : "OK"
+>x.zipStr : string
+>x : typeof x
+>zipStr : string
+>"OK" : "OK"
+
+x.lastName = "should fail";
+>x.lastName = "should fail" : "should fail"
+>x.lastName : any
+>x : typeof x
+>lastName : any
+>"should fail" : "should fail"
+
+x.houseNumber = 12; // should also fail
+>x.houseNumber = 12 : 12
+>x.houseNumber : any
+>x : typeof x
+>houseNumber : any
+>12 : 12
+
+x.zipStr = 12; // should fail
+>x.zipStr = 12 : 12
+>x.zipStr : string
+>x : typeof x
+>zipStr : string
+>12 : 12
+
+x.middleInit = "R"; // should also fail
+>x.middleInit = "R" : "R"
+>x.middleInit : any
+>x : typeof x
+>middleInit : any
+>"R" : "R"
+
+=== tests/cases/conformance/jsdoc/index.js ===
+const x = {};
+>x : typeof x
+>{} : {}
+
+Object.defineProperty(x, "name", { value: "Charles", writable: true });
+>Object.defineProperty(x, "name", { value: "Charles", writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>x : typeof x
+>"name" : "name"
+>{ value: "Charles", writable: true } : { value: string; writable: true; }
+>value : string
+>"Charles" : "Charles"
+>writable : true
+>true : true
+
+Object.defineProperty(x, "middleInit", { value: "H" });
+>Object.defineProperty(x, "middleInit", { value: "H" }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>x : typeof x
+>"middleInit" : "middleInit"
+>{ value: "H" } : { value: string; }
+>value : string
+>"H" : "H"
+
+Object.defineProperty(x, "lastName", { value: "Smith", writable: false });
+>Object.defineProperty(x, "lastName", { value: "Smith", writable: false }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>x : typeof x
+>"lastName" : "lastName"
+>{ value: "Smith", writable: false } : { value: string; writable: false; }
+>value : string
+>"Smith" : "Smith"
+>writable : false
+>false : false
+
+Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } });
+>Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>x : typeof x
+>"zip" : "zip"
+>{ get() { return 98122 }, set(_) { /*ignore*/ } } : { get(): number; set(_: any): void; }
+>get : () => number
+>98122 : 98122
+>set : (_: any) => void
+>_ : any
+
+Object.defineProperty(x, "houseNumber", { get() { return 21.75 } });
+>Object.defineProperty(x, "houseNumber", { get() { return 21.75 } }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>x : typeof x
+>"houseNumber" : "houseNumber"
+>{ get() { return 21.75 } } : { get(): number; }
+>get : () => number
+>21.75 : 21.75
+
+Object.defineProperty(x, "zipStr", {
+>Object.defineProperty(x, "zipStr", {    /** @param {string} str */    set(str) {        this.zip = Number(str)     }}) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>x : typeof x
+>"zipStr" : "zipStr"
+>{    /** @param {string} str */    set(str) {        this.zip = Number(str)     }} : { set(str: string): void; }
+
+    /** @param {string} str */
+    set(str) {
+>set : (str: string) => void
+>str : string
+
+        this.zip = Number(str) 
+>this.zip = Number(str) : number
+>this.zip : any
+>this : any
+>zip : any
+>Number(str) : number
+>Number : NumberConstructor
+>str : string
+    }
+});
+
+/**
+ * @param {{name: string}} named
+ */
+function takeName(named) { return named.name; }
+>takeName : (named: { name: string; }) => string
+>named : { name: string; }
+>named.name : string
+>named : { name: string; }
+>name : string
+
+takeName(x);
+>takeName(x) : string
+>takeName : (named: { name: string; }) => string
+>x : typeof x
+
+/**
+ * @type {number}
+ */
+var a = x.zip;
+>a : number
+>x.zip : number
+>x : typeof x
+>zip : number
+
+/**
+ * @type {number}
+ */
+var b = x.houseNumber;
+>b : number
+>x.houseNumber : number
+>x : typeof x
+>houseNumber : number
+
+const returnExemplar = () => x;
+>returnExemplar : () => typeof x
+>() => x : () => typeof x
+>x : typeof x
+
+const needsExemplar = (_ = x) => void 0;
+>needsExemplar : (_?: typeof x) => undefined
+>(_ = x) => void 0 : (_?: typeof x) => undefined
+>_ : typeof x
+>x : typeof x
+>void 0 : undefined
+>0 : 0
+
+const expected = /** @type {{name: string, readonly middleInit: string, readonly lastName: string, zip: number, readonly houseNumber: number, zipStr: string}} */(/** @type {*} */(null));
+>expected : { name: string; readonly middleInit: string; readonly lastName: string; zip: number; readonly houseNumber: number; zipStr: string; }
+>(/** @type {*} */(null)) : { name: string; readonly middleInit: string; readonly lastName: string; zip: number; readonly houseNumber: number; zipStr: string; }
+>(null) : any
+>null : null
+
+/**
+ * 
+ * @param {typeof returnExemplar} a 
+ * @param {typeof needsExemplar} b 
+ */
+function match(a, b) {}
+>match : (a: () => typeof x, b: (_?: typeof x) => undefined) => void
+>a : () => typeof x
+>b : (_?: typeof x) => undefined
+
+match(() => expected, (x = expected) => void 0);
+>match(() => expected, (x = expected) => void 0) : void
+>match : (a: () => typeof x, b: (_?: typeof x) => undefined) => void
+>() => expected : () => { name: string; readonly middleInit: string; readonly lastName: string; zip: number; readonly houseNumber: number; zipStr: string; }
+>expected : { name: string; readonly middleInit: string; readonly lastName: string; zip: number; readonly houseNumber: number; zipStr: string; }
+>(x = expected) => void 0 : (x?: typeof x | undefined) => undefined
+>x : typeof x | undefined
+>expected : { name: string; readonly middleInit: string; readonly lastName: string; zip: number; readonly houseNumber: number; zipStr: string; }
+>void 0 : undefined
+>0 : 0
+
+module.exports = x;
+>module.exports = x : typeof x
+>module.exports : typeof x
+>module : { "tests/cases/conformance/jsdoc/index": typeof x; }
+>exports : typeof x
+>x : typeof x
+
diff --git a/tests/baselines/reference/checkOtherObjectAssignProperty.errors.txt b/tests/baselines/reference/checkOtherObjectAssignProperty.errors.txt
new file mode 100644
index 0000000000000..146550d6fb62e
--- /dev/null
+++ b/tests/baselines/reference/checkOtherObjectAssignProperty.errors.txt
@@ -0,0 +1,58 @@
+tests/cases/conformance/jsdoc/importer.js(3,5): error TS2339: Property 'other' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+tests/cases/conformance/jsdoc/importer.js(4,5): error TS2339: Property 'prop' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+tests/cases/conformance/jsdoc/importer.js(11,5): error TS2339: Property 'other' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+tests/cases/conformance/jsdoc/importer.js(12,5): error TS2339: Property 'prop' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+tests/cases/conformance/jsdoc/importer.js(13,5): error TS2540: Cannot assign to 'bad1' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/importer.js(14,5): error TS2540: Cannot assign to 'bad2' because it is a constant or a read-only property.
+tests/cases/conformance/jsdoc/importer.js(15,5): error TS2540: Cannot assign to 'bad3' because it is a constant or a read-only property.
+
+
+==== tests/cases/conformance/jsdoc/importer.js (7 errors) ====
+    const mod = require("./mod1");
+    mod.thing;
+    mod.other;
+        ~~~~~
+!!! error TS2339: Property 'other' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+    mod.prop;
+        ~~~~
+!!! error TS2339: Property 'prop' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+    mod.bad1;
+    mod.bad2;
+    mod.bad3;
+    
+    
+    mod.thing = 0;
+    mod.other = 0;
+        ~~~~~
+!!! error TS2339: Property 'other' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+    mod.prop = 0;
+        ~~~~
+!!! error TS2339: Property 'prop' does not exist on type 'typeof import("tests/cases/conformance/jsdoc/mod1")'.
+    mod.bad1 = 0;
+        ~~~~
+!!! error TS2540: Cannot assign to 'bad1' because it is a constant or a read-only property.
+    mod.bad2 = 0;
+        ~~~~
+!!! error TS2540: Cannot assign to 'bad2' because it is a constant or a read-only property.
+    mod.bad3 = 0;
+        ~~~~
+!!! error TS2540: Cannot assign to 'bad3' because it is a constant or a read-only property.
+    
+==== tests/cases/conformance/jsdoc/mod1.js (0 errors) ====
+    const obj = { value: 42, writable: true };
+    Object.defineProperty(exports, "thing", obj);
+    
+    /**
+     * @type {string}
+     */
+    let str = /** @type {string} */("other");
+    Object.defineProperty(exports, str, { value: 42, writable: true });
+    
+    const propName = "prop"
+    Object.defineProperty(exports, propName, { value: 42, writable: true });
+    
+    
+    Object.defineProperty(exports, "bad1", { });
+    Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" });
+    Object.defineProperty(exports, "bad3", { writable: true });
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/checkOtherObjectAssignProperty.symbols b/tests/baselines/reference/checkOtherObjectAssignProperty.symbols
new file mode 100644
index 0000000000000..efc0a46315602
--- /dev/null
+++ b/tests/baselines/reference/checkOtherObjectAssignProperty.symbols
@@ -0,0 +1,121 @@
+=== tests/cases/conformance/jsdoc/importer.js ===
+const mod = require("./mod1");
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>require : Symbol(require)
+>"./mod1" : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+
+mod.thing;
+>mod.thing : Symbol("thing", Decl(mod1.js, 0, 42))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>thing : Symbol("thing", Decl(mod1.js, 0, 42))
+
+mod.other;
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+
+mod.prop;
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+
+mod.bad1;
+>mod.bad1 : Symbol("bad1", Decl(mod1.js, 10, 72))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>bad1 : Symbol("bad1", Decl(mod1.js, 10, 72))
+
+mod.bad2;
+>mod.bad2 : Symbol("bad2", Decl(mod1.js, 13, 44))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>bad2 : Symbol("bad2", Decl(mod1.js, 13, 44))
+
+mod.bad3;
+>mod.bad3 : Symbol("bad3", Decl(mod1.js, 14, 77))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>bad3 : Symbol("bad3", Decl(mod1.js, 14, 77))
+
+
+mod.thing = 0;
+>mod.thing : Symbol("thing", Decl(mod1.js, 0, 42))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>thing : Symbol("thing", Decl(mod1.js, 0, 42))
+
+mod.other = 0;
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+
+mod.prop = 0;
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+
+mod.bad1 = 0;
+>mod.bad1 : Symbol("bad1", Decl(mod1.js, 10, 72))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>bad1 : Symbol("bad1", Decl(mod1.js, 10, 72))
+
+mod.bad2 = 0;
+>mod.bad2 : Symbol("bad2", Decl(mod1.js, 13, 44))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>bad2 : Symbol("bad2", Decl(mod1.js, 13, 44))
+
+mod.bad3 = 0;
+>mod.bad3 : Symbol("bad3", Decl(mod1.js, 14, 77))
+>mod : Symbol(mod, Decl(importer.js, 0, 5), Decl(importer.js, 6, 9))
+>bad3 : Symbol("bad3", Decl(mod1.js, 14, 77))
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+const obj = { value: 42, writable: true };
+>obj : Symbol(obj, Decl(mod1.js, 0, 5))
+>value : Symbol(value, Decl(mod1.js, 0, 13))
+>writable : Symbol(writable, Decl(mod1.js, 0, 24))
+
+Object.defineProperty(exports, "thing", obj);
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>obj : Symbol(obj, Decl(mod1.js, 0, 5))
+
+/**
+ * @type {string}
+ */
+let str = /** @type {string} */("other");
+>str : Symbol(str, Decl(mod1.js, 6, 3))
+
+Object.defineProperty(exports, str, { value: 42, writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>str : Symbol(str, Decl(mod1.js, 6, 3))
+>value : Symbol(value, Decl(mod1.js, 7, 37))
+>writable : Symbol(writable, Decl(mod1.js, 7, 48))
+
+const propName = "prop"
+>propName : Symbol(propName, Decl(mod1.js, 9, 5))
+
+Object.defineProperty(exports, propName, { value: 42, writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>propName : Symbol(propName, Decl(mod1.js, 9, 5))
+>value : Symbol(value, Decl(mod1.js, 10, 42))
+>writable : Symbol(writable, Decl(mod1.js, 10, 53))
+
+
+Object.defineProperty(exports, "bad1", { });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+
+Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>get : Symbol(get, Decl(mod1.js, 14, 40))
+>value : Symbol(value, Decl(mod1.js, 14, 61))
+
+Object.defineProperty(exports, "bad3", { writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>exports : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+>writable : Symbol(writable, Decl(mod1.js, 15, 40))
+
diff --git a/tests/baselines/reference/checkOtherObjectAssignProperty.types b/tests/baselines/reference/checkOtherObjectAssignProperty.types
new file mode 100644
index 0000000000000..d9b68d71745e8
--- /dev/null
+++ b/tests/baselines/reference/checkOtherObjectAssignProperty.types
@@ -0,0 +1,170 @@
+=== tests/cases/conformance/jsdoc/importer.js ===
+const mod = require("./mod1");
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>require("./mod1") : typeof import("tests/cases/conformance/jsdoc/mod1")
+>require : any
+>"./mod1" : "./mod1"
+
+mod.thing;
+>mod.thing : number
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>thing : number
+
+mod.other;
+>mod.other : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>other : any
+
+mod.prop;
+>mod.prop : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>prop : any
+
+mod.bad1;
+>mod.bad1 : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>bad1 : any
+
+mod.bad2;
+>mod.bad2 : string
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>bad2 : string
+
+mod.bad3;
+>mod.bad3 : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>bad3 : any
+
+
+mod.thing = 0;
+>mod.thing = 0 : 0
+>mod.thing : number
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>thing : number
+>0 : 0
+
+mod.other = 0;
+>mod.other = 0 : 0
+>mod.other : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>other : any
+>0 : 0
+
+mod.prop = 0;
+>mod.prop = 0 : 0
+>mod.prop : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>prop : any
+>0 : 0
+
+mod.bad1 = 0;
+>mod.bad1 = 0 : 0
+>mod.bad1 : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>bad1 : any
+>0 : 0
+
+mod.bad2 = 0;
+>mod.bad2 = 0 : 0
+>mod.bad2 : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>bad2 : any
+>0 : 0
+
+mod.bad3 = 0;
+>mod.bad3 = 0 : 0
+>mod.bad3 : any
+>mod : typeof import("tests/cases/conformance/jsdoc/mod1")
+>bad3 : any
+>0 : 0
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+const obj = { value: 42, writable: true };
+>obj : { value: number; writable: boolean; }
+>{ value: 42, writable: true } : { value: number; writable: boolean; }
+>value : number
+>42 : 42
+>writable : boolean
+>true : true
+
+Object.defineProperty(exports, "thing", obj);
+>Object.defineProperty(exports, "thing", obj) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"thing" : "thing"
+>obj : { value: number; writable: boolean; }
+
+/**
+ * @type {string}
+ */
+let str = /** @type {string} */("other");
+>str : string
+>("other") : string
+>"other" : "other"
+
+Object.defineProperty(exports, str, { value: 42, writable: true });
+>Object.defineProperty(exports, str, { value: 42, writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>str : string
+>{ value: 42, writable: true } : { value: number; writable: true; }
+>value : number
+>42 : 42
+>writable : true
+>true : true
+
+const propName = "prop"
+>propName : "prop"
+>"prop" : "prop"
+
+Object.defineProperty(exports, propName, { value: 42, writable: true });
+>Object.defineProperty(exports, propName, { value: 42, writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>propName : "prop"
+>{ value: 42, writable: true } : { value: number; writable: true; }
+>value : number
+>42 : 42
+>writable : true
+>true : true
+
+
+Object.defineProperty(exports, "bad1", { });
+>Object.defineProperty(exports, "bad1", { }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"bad1" : "bad1"
+>{ } : {}
+
+Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" });
+>Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"bad2" : "bad2"
+>{ get() { return 12 }, value: "no" } : { get(): number; value: string; }
+>get : () => number
+>12 : 12
+>value : string
+>"no" : "no"
+
+Object.defineProperty(exports, "bad3", { writable: true });
+>Object.defineProperty(exports, "bad3", { writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>"bad3" : "bad3"
+>{ writable: true } : { writable: true; }
+>writable : true
+>true : true
+
diff --git a/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.errors.txt b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.errors.txt
new file mode 100644
index 0000000000000..d7c036abacf3a
--- /dev/null
+++ b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.errors.txt
@@ -0,0 +1,23 @@
+tests/cases/compiler/namespacer.js(2,1): error TS2323: Cannot redeclare exported variable 'NS'.
+tests/cases/compiler/namespacer.js(3,1): error TS2323: Cannot redeclare exported variable 'NS'.
+
+
+==== tests/cases/compiler/index.js (0 errors) ====
+    const _item = require("./namespacer");
+    module.exports = 12;
+    Object.defineProperty(module, "exports", { value: "oh no" });
+    
+==== tests/cases/compiler/namespacey.js (0 errors) ====
+    const A = {}
+    A.bar = class Q {}
+    module.exports = A;
+==== tests/cases/compiler/namespacer.js (2 errors) ====
+    const B = {}
+    B.NS = require("./namespacey");
+    ~~~~
+!!! error TS2323: Cannot redeclare exported variable 'NS'.
+    Object.defineProperty(B, "NS", { value: "why though", writable: true });
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2323: Cannot redeclare exported variable 'NS'.
+    module.exports = B;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.symbols b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.symbols
new file mode 100644
index 0000000000000..5b0883f227ac4
--- /dev/null
+++ b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.symbols
@@ -0,0 +1,59 @@
+=== tests/cases/compiler/index.js ===
+const _item = require("./namespacer");
+>_item : Symbol(_item, Decl(index.js, 0, 5))
+>require : Symbol(require)
+>"./namespacer" : Symbol("tests/cases/compiler/namespacer", Decl(namespacer.js, 0, 0))
+
+module.exports = 12;
+>module.exports : Symbol("tests/cases/compiler/index", Decl(index.js, 0, 0))
+>module : Symbol(export=, Decl(index.js, 0, 38))
+>exports : Symbol(export=, Decl(index.js, 0, 38))
+
+Object.defineProperty(module, "exports", { value: "oh no" });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>module : Symbol(module, Decl(index.js, 0, 38), Decl(index.js, 2, 22))
+>value : Symbol(value, Decl(index.js, 2, 42))
+
+=== tests/cases/compiler/namespacey.js ===
+const A = {}
+>A : Symbol(A, Decl(namespacey.js, 0, 5), Decl(namespacey.js, 0, 12))
+
+A.bar = class Q {}
+>A.bar : Symbol(A.bar, Decl(namespacey.js, 0, 12))
+>A : Symbol(A, Decl(namespacey.js, 0, 5), Decl(namespacey.js, 0, 12))
+>bar : Symbol(A.bar, Decl(namespacey.js, 0, 12))
+>Q : Symbol(Q, Decl(namespacey.js, 1, 7))
+
+module.exports = A;
+>module.exports : Symbol("tests/cases/compiler/namespacey", Decl(namespacey.js, 0, 0))
+>module : Symbol(export=, Decl(namespacey.js, 1, 18))
+>exports : Symbol(export=, Decl(namespacey.js, 1, 18))
+>A : Symbol(A, Decl(namespacey.js, 0, 5), Decl(namespacey.js, 0, 12))
+
+=== tests/cases/compiler/namespacer.js ===
+const B = {}
+>B : Symbol(B, Decl(namespacer.js, 0, 5), Decl(namespacer.js, 0, 12))
+
+B.NS = require("./namespacey");
+>B.NS : Symbol(B.NS, Decl(namespacer.js, 0, 12), Decl(namespacer.js, 1, 31))
+>B : Symbol(B, Decl(namespacer.js, 0, 5), Decl(namespacer.js, 0, 12))
+>NS : Symbol(B.NS, Decl(namespacer.js, 0, 12), Decl(namespacer.js, 1, 31))
+>require : Symbol(require)
+>"./namespacey" : Symbol("tests/cases/compiler/namespacey", Decl(namespacey.js, 0, 0))
+
+Object.defineProperty(B, "NS", { value: "why though", writable: true });
+>Object.defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>defineProperty : Symbol(ObjectConstructor.defineProperty, Decl(lib.es5.d.ts, --, --))
+>B : Symbol(B, Decl(namespacer.js, 0, 5), Decl(namespacer.js, 0, 12))
+>value : Symbol(value, Decl(namespacer.js, 2, 32))
+>writable : Symbol(writable, Decl(namespacer.js, 2, 53))
+
+module.exports = B;
+>module.exports : Symbol("tests/cases/compiler/namespacer", Decl(namespacer.js, 0, 0))
+>module : Symbol(export=, Decl(namespacer.js, 2, 72))
+>exports : Symbol(export=, Decl(namespacer.js, 2, 72))
+>B : Symbol(B, Decl(namespacer.js, 0, 5), Decl(namespacer.js, 0, 12))
+
diff --git a/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types
new file mode 100644
index 0000000000000..ebd6f7ba4342d
--- /dev/null
+++ b/tests/baselines/reference/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.types
@@ -0,0 +1,79 @@
+=== tests/cases/compiler/index.js ===
+const _item = require("./namespacer");
+>_item : typeof B
+>require("./namespacer") : typeof B
+>require : any
+>"./namespacer" : "./namespacer"
+
+module.exports = 12;
+>module.exports = 12 : number
+>module.exports : number
+>module : typeof module
+>exports : number
+>12 : 12
+
+Object.defineProperty(module, "exports", { value: "oh no" });
+>Object.defineProperty(module, "exports", { value: "oh no" }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>module : typeof module
+>"exports" : "exports"
+>{ value: "oh no" } : { value: string; }
+>value : string
+>"oh no" : "oh no"
+
+=== tests/cases/compiler/namespacey.js ===
+const A = {}
+>A : typeof A
+>{} : {}
+
+A.bar = class Q {}
+>A.bar = class Q {} : typeof Q
+>A.bar : typeof Q
+>A : typeof A
+>bar : typeof Q
+>class Q {} : typeof Q
+>Q : typeof Q
+
+module.exports = A;
+>module.exports = A : typeof A
+>module.exports : typeof A
+>module : { "tests/cases/compiler/namespacey": typeof A; }
+>exports : typeof A
+>A : typeof A
+
+=== tests/cases/compiler/namespacer.js ===
+const B = {}
+>B : typeof B
+>{} : {}
+
+B.NS = require("./namespacey");
+>B.NS = require("./namespacey") : typeof A
+>B.NS : string | typeof A
+>B : typeof B
+>NS : string | typeof A
+>require("./namespacey") : typeof A
+>require : any
+>"./namespacey" : "./namespacey"
+
+Object.defineProperty(B, "NS", { value: "why though", writable: true });
+>Object.defineProperty(B, "NS", { value: "why though", writable: true }) : any
+>Object.defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>Object : ObjectConstructor
+>defineProperty : (o: any, p: string | number | symbol, attributes: PropertyDescriptor & ThisType<any>) => any
+>B : typeof B
+>"NS" : "NS"
+>{ value: "why though", writable: true } : { value: string; writable: true; }
+>value : string
+>"why though" : "why though"
+>writable : true
+>true : true
+
+module.exports = B;
+>module.exports = B : typeof B
+>module.exports : typeof B
+>module : { "tests/cases/compiler/namespacer": typeof B; }
+>exports : typeof B
+>B : typeof B
+
diff --git a/tests/cases/compiler/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.ts b/tests/cases/compiler/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.ts
new file mode 100644
index 0000000000000..a0c0b325adf67
--- /dev/null
+++ b/tests/cases/compiler/ensureNoCrashExportAssignmentDefineProperrtyPotentialMerge.ts
@@ -0,0 +1,17 @@
+// @allowJs: true
+// @noEmit: true
+// @checkJs: true
+// @filename: namespacey.js
+const A = {}
+A.bar = class Q {}
+module.exports = A;
+// @filename: namespacer.js
+const B = {}
+B.NS = require("./namespacey");
+Object.defineProperty(B, "NS", { value: "why though", writable: true });
+module.exports = B;
+
+// @filename: index.js
+const _item = require("./namespacer");
+module.exports = 12;
+Object.defineProperty(module, "exports", { value: "oh no" });
diff --git a/tests/cases/conformance/jsdoc/checkExportsObjectAssignProperty.ts b/tests/cases/conformance/jsdoc/checkExportsObjectAssignProperty.ts
new file mode 100644
index 0000000000000..132fef0451028
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/checkExportsObjectAssignProperty.ts
@@ -0,0 +1,82 @@
+// @allowJs: true
+// @noEmit: true
+// @strict: true
+// @checkJs: true
+// @filename: mod1.js
+Object.defineProperty(exports, "thing", { value: 42, writable: true });
+Object.defineProperty(exports, "readonlyProp", { value: "Smith", writable: false });
+Object.defineProperty(exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+Object.defineProperty(exports, "readonlyAccessor", { get() { return 21.75 } });
+Object.defineProperty(exports, "setonlyAccessor", {
+    /** @param {string} str */
+    set(str) {
+        this.rwAccessors = Number(str) 
+    }
+});
+
+// @filename: mod2.js
+Object.defineProperty(module.exports, "thing", { value: "yes", writable: true });
+Object.defineProperty(module.exports, "readonlyProp", { value: "Smith", writable: false });
+Object.defineProperty(module.exports, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+Object.defineProperty(module.exports, "readonlyAccessor", { get() { return 21.75 } });
+Object.defineProperty(module.exports, "setonlyAccessor", {
+    /** @param {string} str */
+    set(str) {
+        this.rwAccessors = Number(str) 
+    }
+});
+
+// @filename: index.js
+
+/**
+ * @type {number}
+ */
+const q = require("./mod1").thing;
+
+/**
+ * @type {string}
+ */
+const u = require("./mod2").thing;
+
+// @filename: validator.ts
+import "./";
+
+import m1 = require("./mod1");
+
+m1.thing;
+m1.readonlyProp;
+m1.rwAccessors;
+m1.readonlyAccessor;
+m1.setonlyAccessor;
+
+// allowed assignments
+m1.thing = 10;
+m1.rwAccessors = 11;
+m1.setonlyAccessor = "yes";
+
+// disallowed assignments
+m1.readonlyProp = "name";
+m1.readonlyAccessor = 12;
+m1.thing = "no";
+m1.rwAccessors = "no";
+m1.setonlyAccessor = 0;
+
+import m2 = require("./mod2");
+
+m2.thing;
+m2.readonlyProp;
+m2.rwAccessors;
+m2.readonlyAccessor;
+m2.setonlyAccessor;
+
+// allowed assignments
+m2.thing = "ok";
+m2.rwAccessors = 11;
+m2.setonlyAccessor = "yes";
+
+// disallowed assignments
+m2.readonlyProp = "name";
+m2.readonlyAccessor = 12;
+m2.thing = 0;
+m2.rwAccessors = "no";
+m2.setonlyAccessor = 0;
diff --git a/tests/cases/conformance/jsdoc/checkExportsObjectAssignPrototypeProperty.ts b/tests/cases/conformance/jsdoc/checkExportsObjectAssignPrototypeProperty.ts
new file mode 100644
index 0000000000000..9518e05264654
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/checkExportsObjectAssignPrototypeProperty.ts
@@ -0,0 +1,52 @@
+// @allowJs: true
+// @noEmit: true
+// @strict: true
+// @checkJs: true
+// @filename: mod1.js
+/**
+ * @constructor
+ * @param {string} name
+ */
+function Person(name) {
+    this.name = name;
+}
+Person.prototype.describe = function () {
+    return "Person called " + this.name;
+};
+Object.defineProperty(Person.prototype, "thing", { value: 42, writable: true });
+Object.defineProperty(Person.prototype, "readonlyProp", { value: "Smith", writable: false });
+Object.defineProperty(Person.prototype, "rwAccessors", { get() { return 98122 }, set(_) { /*ignore*/ } });
+Object.defineProperty(Person.prototype, "readonlyAccessor", { get() { return 21.75 } });
+Object.defineProperty(Person.prototype, "setonlyAccessor", {
+    /** @param {string} str */
+    set(str) {
+        this.rwAccessors = Number(str)
+    }
+});
+module.exports = Person;
+
+// @filename: validator.ts
+import "./";
+
+import Person = require("./mod1");
+
+const m1 = new Person("Name")
+
+m1.thing;
+m1.readonlyProp;
+m1.rwAccessors;
+m1.readonlyAccessor;
+m1.setonlyAccessor;
+
+// allowed assignments
+m1.thing = 10;
+m1.rwAccessors = 11;
+m1.setonlyAccessor = "yes";
+
+// disallowed assignments
+m1.readonlyProp = "name";
+m1.readonlyAccessor = 12;
+m1.thing = "no";
+m1.rwAccessors = "no";
+m1.setonlyAccessor = 0;
+
diff --git a/tests/cases/conformance/jsdoc/checkObjectDefineProperty.ts b/tests/cases/conformance/jsdoc/checkObjectDefineProperty.ts
new file mode 100644
index 0000000000000..d0ba377b000c6
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/checkObjectDefineProperty.ts
@@ -0,0 +1,68 @@
+// @allowJs: true
+// @noEmit: true
+// @strict: true
+// @checkJs: true
+// @filename: index.js
+const x = {};
+Object.defineProperty(x, "name", { value: "Charles", writable: true });
+Object.defineProperty(x, "middleInit", { value: "H" });
+Object.defineProperty(x, "lastName", { value: "Smith", writable: false });
+Object.defineProperty(x, "zip", { get() { return 98122 }, set(_) { /*ignore*/ } });
+Object.defineProperty(x, "houseNumber", { get() { return 21.75 } });
+Object.defineProperty(x, "zipStr", {
+    /** @param {string} str */
+    set(str) {
+        this.zip = Number(str) 
+    }
+});
+
+/**
+ * @param {{name: string}} named
+ */
+function takeName(named) { return named.name; }
+
+takeName(x);
+/**
+ * @type {number}
+ */
+var a = x.zip;
+
+/**
+ * @type {number}
+ */
+var b = x.houseNumber;
+
+const returnExemplar = () => x;
+const needsExemplar = (_ = x) => void 0;
+
+const expected = /** @type {{name: string, readonly middleInit: string, readonly lastName: string, zip: number, readonly houseNumber: number, zipStr: string}} */(/** @type {*} */(null));
+
+/**
+ * 
+ * @param {typeof returnExemplar} a 
+ * @param {typeof needsExemplar} b 
+ */
+function match(a, b) {}
+
+match(() => expected, (x = expected) => void 0);
+
+module.exports = x;
+
+// @filename: validate.ts
+// Validate in TS as simple validations would usually be interpreted as more special assignments
+import x = require("./");
+x.name;
+x.middleInit;
+x.lastName;
+x.zip;
+x.houseNumber;
+x.zipStr;
+
+x.name = "Another";
+x.zip = 98123;
+x.zipStr = "OK";
+
+x.lastName = "should fail";
+x.houseNumber = 12; // should also fail
+x.zipStr = 12; // should fail
+x.middleInit = "R"; // should also fail
diff --git a/tests/cases/conformance/jsdoc/checkOtherObjectAssignProperty.ts b/tests/cases/conformance/jsdoc/checkOtherObjectAssignProperty.ts
new file mode 100644
index 0000000000000..a7bccc65283a0
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/checkOtherObjectAssignProperty.ts
@@ -0,0 +1,39 @@
+// @allowJs: true
+// @noEmit: true
+// @strict: true
+// @checkJs: true
+// @filename: mod1.js
+
+const obj = { value: 42, writable: true };
+Object.defineProperty(exports, "thing", obj);
+
+/**
+ * @type {string}
+ */
+let str = /** @type {string} */("other");
+Object.defineProperty(exports, str, { value: 42, writable: true });
+
+const propName = "prop"
+Object.defineProperty(exports, propName, { value: 42, writable: true });
+
+
+Object.defineProperty(exports, "bad1", { });
+Object.defineProperty(exports, "bad2", { get() { return 12 }, value: "no" });
+Object.defineProperty(exports, "bad3", { writable: true });
+
+// @filename: importer.js
+const mod = require("./mod1");
+mod.thing;
+mod.other;
+mod.prop;
+mod.bad1;
+mod.bad2;
+mod.bad3;
+
+
+mod.thing = 0;
+mod.other = 0;
+mod.prop = 0;
+mod.bad1 = 0;
+mod.bad2 = 0;
+mod.bad3 = 0;
diff --git a/tests/cases/fourslash/syntheticImportFromBabelGeneratedFile1.ts b/tests/cases/fourslash/syntheticImportFromBabelGeneratedFile1.ts
new file mode 100644
index 0000000000000..4dd0654a897df
--- /dev/null
+++ b/tests/cases/fourslash/syntheticImportFromBabelGeneratedFile1.ts
@@ -0,0 +1,20 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @allowSyntheticDefaultImports: true
+
+// @Filename: /a.js
+////exports.__esModule = true;
+////exports.default = f;
+/////**
+//// * Run this function
+//// * @param {string} t
+//// */
+////function f(t) {}
+
+// @Filename: /b.js
+////import f from "./a"
+/////**/f
+
+verify.quickInfoAt("", `(alias) (property) f: (t: string) => void
+import f`, "Run this function"); // Passes
\ No newline at end of file
diff --git a/tests/cases/fourslash/syntheticImportFromBabelGeneratedFile2.ts b/tests/cases/fourslash/syntheticImportFromBabelGeneratedFile2.ts
new file mode 100644
index 0000000000000..0cfb4e684542c
--- /dev/null
+++ b/tests/cases/fourslash/syntheticImportFromBabelGeneratedFile2.ts
@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts'/>
+
+// @allowJs: true
+// @allowSyntheticDefaultImports: true
+
+// @Filename: /a.js
+////Object.defineProperty(exports, "__esModule", {
+////    value: true
+////});
+////exports.default = f;
+/////**
+//// * Run this function
+//// * @param {string} t
+//// */
+////function f(t) {}
+
+// @Filename: /b.js
+////import f from "./a"
+/////**/f
+
+verify.quickInfoAt("", `(alias) (property) f: (t: string) => void
+import f`, "Run this function"); // Passes
\ No newline at end of file