Generic object rest variables and parameters

src/compiler/checker.ts

@@ -520,6 +520,8 @@ namespace ts {
         let deferredGlobalTemplateStringsArrayType: ObjectType;
         let deferredGlobalImportMetaType: ObjectType;
         let deferredGlobalExtractSymbol: Symbol;
+        let deferredGlobalExcludeSymbol: Symbol;
+        let deferredGlobalPickSymbol: Symbol;
         let deferredGlobalBigIntType: ObjectType;
 
         const allPotentiallyUnusedIdentifiers = createMap<PotentiallyUnusedIdentifier[]>(); // key is file name
@@ -4622,18 +4624,25 @@ namespace ts {
             if (source.flags & TypeFlags.Never) {
                 return emptyObjectType;
             }
-
             if (source.flags & TypeFlags.Union) {
                 return mapType(source, t => getRestType(t, properties, symbol));
             }
-
-            const members = createSymbolTable();
-            const names = createUnderscoreEscapedMap<true>();
-            for (const name of properties) {
-                names.set(getTextOfPropertyName(name), true);
+            const omitKeyType = getUnionType(map(properties, getLiteralTypeFromPropertyName));
+            if (isGenericObjectType(source) || isGenericIndexType(omitKeyType)) {
+                if (omitKeyType.flags & TypeFlags.Never) {
+                    return source;
+                }
+                const pickTypeAlias = getGlobalPickSymbol();
+                const excludeTypeAlias = getGlobalExcludeSymbol();
+                if (!pickTypeAlias || !excludeTypeAlias) {
+                    return errorType;
+                }
+                const pickKeys = getTypeAliasInstantiation(excludeTypeAlias, [getIndexType(source), omitKeyType]);
+                return getTypeAliasInstantiation(pickTypeAlias, [source, pickKeys]);
             }
+            const members = createSymbolTable();
             for (const prop of getPropertiesOfType(source)) {
-                if (!names.has(prop.escapedName)
+                if (!isTypeAssignableTo(getLiteralTypeFromProperty(prop, TypeFlags.StringOrNumberLiteralOrUnique), omitKeyType)
                     && !(getDeclarationModifierFlagsFromSymbol(prop) & (ModifierFlags.Private | ModifierFlags.Protected))
                     && isSpreadableProperty(prop)) {
                     members.set(prop.escapedName, getSpreadSymbol(prop));
@@ -4669,7 +4678,7 @@ namespace ts {
             let type: Type | undefined;
             if (pattern.kind === SyntaxKind.ObjectBindingPattern) {
                 if (declaration.dotDotDotToken) {
-                    if (parentType.flags & TypeFlags.Unknown || !isValidSpreadType(parentType) || isGenericObjectType(parentType)) {
+                    if (parentType.flags & TypeFlags.Unknown || !isValidSpreadType(parentType)) {
                         error(declaration, Diagnostics.Rest_types_may_only_be_created_from_object_types);
                         return errorType;
                     }
@@ -4684,12 +4693,8 @@ namespace ts {
                 else {
                     // Use explicitly specified property name ({ p: xxx } form), or otherwise the implied name ({ p } form)
                     const name = declaration.propertyName || <Identifier>declaration.name;
-                    const exprType = isComputedPropertyName(name)
-                        ? checkComputedPropertyName(name)
-                        : isIdentifier(name)
-                            ? getLiteralType(unescapeLeadingUnderscores(name.escapedText))
-                            : checkExpression(name);
-                    const declaredType = checkIndexedAccessIndexType(getIndexedAccessType(getApparentType(parentType), exprType, name), name);
+                    const exprType = getLiteralTypeFromPropertyName(name);
+                    const declaredType = checkIndexedAccessIndexType(getIndexedAccessType(parentType, exprType, name), name);
                     type = getFlowTypeOfReference(declaration, getConstraintForLocation(declaredType, declaration.name));
                 }
             }
@@ -6825,7 +6830,7 @@ namespace ts {
             if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
                 // We have a { [P in keyof T]: X }
                 for (const prop of getPropertiesOfType(modifiersType)) {
-                    addMemberForKeyType(getLiteralTypeFromPropertyName(prop, include));
+                    addMemberForKeyType(getLiteralTypeFromProperty(prop, include));
                 }
                 if (modifiersType.flags & TypeFlags.Any || getIndexInfoOfType(modifiersType, IndexKind.String)) {
                     addMemberForKeyType(stringType);
@@ -8677,6 +8682,14 @@ namespace ts {
             return deferredGlobalExtractSymbol || (deferredGlobalExtractSymbol = getGlobalSymbol("Extract" as __String, SymbolFlags.TypeAlias, Diagnostics.Cannot_find_global_type_0)!); // TODO: GH#18217
         }
 
+        function getGlobalExcludeSymbol(): Symbol {
+            return deferredGlobalExcludeSymbol || (deferredGlobalExcludeSymbol = getGlobalSymbol("Exclude" as __String, SymbolFlags.TypeAlias, Diagnostics.Cannot_find_global_type_0)!); // TODO: GH#18217
+        }
+
+        function getGlobalPickSymbol(): Symbol {
+            return deferredGlobalPickSymbol || (deferredGlobalPickSymbol = getGlobalSymbol("Pick" as __String, SymbolFlags.TypeAlias, Diagnostics.Cannot_find_global_type_0)!); // TODO: GH#18217
+        }
+
         function getGlobalBigIntType(reportErrors: boolean) {
             return deferredGlobalBigIntType || (deferredGlobalBigIntType = getGlobalType("BigInt" as __String, /*arity*/ 0, reportErrors)) || emptyObjectType;
         }
@@ -9268,21 +9281,24 @@ namespace ts {
                 type.resolvedIndexType || (type.resolvedIndexType = createIndexType(type, /*stringsOnly*/ false));
         }
 
+        function getLiteralTypeFromPropertyName(name: PropertyName) {
+            return isIdentifier(name) ? getLiteralType(unescapeLeadingUnderscores(name.escapedText)) :
+                getRegularTypeOfLiteralType(isComputedPropertyName(name) ? checkComputedPropertyName(name) : checkExpression(name));
+        }
+
         function getBigIntLiteralType(node: BigIntLiteral): LiteralType {
             return getLiteralType({
                 negative: false,
                 base10Value: parsePseudoBigInt(node.text)
             });
         }
 
-        function getLiteralTypeFromPropertyName(prop: Symbol, include: TypeFlags) {
+        function getLiteralTypeFromProperty(prop: Symbol, include: TypeFlags) {
             if (!(getDeclarationModifierFlagsFromSymbol(prop) & ModifierFlags.NonPublicAccessibilityModifier)) {
                 let type = getLateBoundSymbol(prop).nameType;
                 if (!type && !isKnownSymbol(prop)) {
-                    const name = prop.valueDeclaration && getNameOfDeclaration(prop.valueDeclaration);
-                    type = name && isNumericLiteral(name) ? getLiteralType(+name.text) :
-                        name && name.kind === SyntaxKind.ComputedPropertyName && isNumericLiteral(name.expression) ? getLiteralType(+name.expression.text) :
-                        getLiteralType(symbolName(prop));
+                    const name = prop.valueDeclaration && getNameOfDeclaration(prop.valueDeclaration) as PropertyName;
+                    type = name && getLiteralTypeFromPropertyName(name) || getLiteralType(symbolName(prop));
                 }
                 if (type && type.flags & include) {
                     return type;
@@ -9291,8 +9307,8 @@ namespace ts {
             return neverType;
         }
 
-        function getLiteralTypeFromPropertyNames(type: Type, include: TypeFlags) {
-            return getUnionType(map(getPropertiesOfType(type), t => getLiteralTypeFromPropertyName(t, include)));
+        function getLiteralTypeFromProperties(type: Type, include: TypeFlags) {
+            return getUnionType(map(getPropertiesOfType(type), t => getLiteralTypeFromProperty(t, include)));
         }
 
         function getNonEnumNumberIndexInfo(type: Type) {
@@ -9307,10 +9323,10 @@ namespace ts {
                 getObjectFlags(type) & ObjectFlags.Mapped ? getConstraintTypeFromMappedType(<MappedType>type) :
                 type === wildcardType ? wildcardType :
                 type.flags & TypeFlags.Any ? keyofConstraintType :
-                stringsOnly ? getIndexInfoOfType(type, IndexKind.String) ? stringType : getLiteralTypeFromPropertyNames(type, TypeFlags.StringLiteral) :
-                getIndexInfoOfType(type, IndexKind.String) ? getUnionType([stringType, numberType, getLiteralTypeFromPropertyNames(type, TypeFlags.UniqueESSymbol)]) :
-                getNonEnumNumberIndexInfo(type) ? getUnionType([numberType, getLiteralTypeFromPropertyNames(type, TypeFlags.StringLiteral | TypeFlags.UniqueESSymbol)]) :
-                getLiteralTypeFromPropertyNames(type, TypeFlags.StringOrNumberLiteralOrUnique);
+                stringsOnly ? getIndexInfoOfType(type, IndexKind.String) ? stringType : getLiteralTypeFromProperties(type, TypeFlags.StringLiteral) :
+                getIndexInfoOfType(type, IndexKind.String) ? getUnionType([stringType, numberType, getLiteralTypeFromProperties(type, TypeFlags.UniqueESSymbol)]) :
+                getNonEnumNumberIndexInfo(type) ? getUnionType([numberType, getLiteralTypeFromProperties(type, TypeFlags.StringLiteral | TypeFlags.UniqueESSymbol)]) :
+                getLiteralTypeFromProperties(type, TypeFlags.StringOrNumberLiteralOrUnique);
         }
 
         function getExtractStringType(type: Type) {
@@ -9563,7 +9579,7 @@ namespace ts {
             // object type. Note that for a generic T and a non-generic K, we eagerly resolve T[K] if it originates in
             // an expression. This is to preserve backwards compatibility. For example, an element access 'this["foo"]'
             // has always been resolved eagerly using the constraint type of 'this' at the given location.
-            if (isGenericIndexType(indexType) || !(accessNode && accessNode.kind === SyntaxKind.ElementAccessExpression) && isGenericObjectType(objectType)) {
+            if (isGenericIndexType(indexType) || !(accessNode && accessNode.kind !== SyntaxKind.IndexedAccessType) && isGenericObjectType(objectType)) {
                 if (objectType.flags & TypeFlags.AnyOrUnknown) {
                     return objectType;
                 }
@@ -11013,7 +11029,7 @@ namespace ts {
             if (!length(node.properties)) return;
             for (const prop of node.properties) {
                 if (isSpreadAssignment(prop)) continue;
-                const type = getLiteralTypeFromPropertyName(getSymbolOfNode(prop), TypeFlags.StringOrNumberLiteralOrUnique);
+                const type = getLiteralTypeFromProperty(getSymbolOfNode(prop), TypeFlags.StringOrNumberLiteralOrUnique);
                 if (!type || (type.flags & TypeFlags.Never)) {
                     continue;
                 }

tests/baselines/reference/computedPropertyNamesContextualType8_ES5.errors.txt

@@ -1,20 +1,21 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts(7,5): error TS2418: Type of computed property's value is 'string', which is not assignable to type 'boolean'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts(8,5): error TS2418: Type of computed property's value is 'number', which is not assignable to type 'boolean'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts(6,5): error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
+  Index signatures are incompatible.
+    Type 'string | number' is not assignable to type 'boolean'.
+      Type 'string' is not assignable to type 'boolean'.
 
 
-==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts (2 errors) ====
+==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts (1 errors) ====
     interface I {
         [s: string]: boolean;
         [s: number]: boolean;
     }
 
     var o: I = {
+        ~
+!!! error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
+!!! error TS2322:   Index signatures are incompatible.
+!!! error TS2322:     Type 'string | number' is not assignable to type 'boolean'.
+!!! error TS2322:       Type 'string' is not assignable to type 'boolean'.
         [""+"foo"]: "",
-        ~~~~~~~~~~
-!!! error TS2418: Type of computed property's value is 'string', which is not assignable to type 'boolean'.
-!!! related TS6501 tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts:2:5: The expected type comes from this index signature.
         [""+"bar"]: 0
-        ~~~~~~~~~~
-!!! error TS2418: Type of computed property's value is 'number', which is not assignable to type 'boolean'.
-!!! related TS6501 tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES5.ts:2:5: The expected type comes from this index signature.
     }

tests/baselines/reference/computedPropertyNamesContextualType8_ES6.errors.txt

@@ -1,20 +1,21 @@
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts(7,5): error TS2418: Type of computed property's value is 'string', which is not assignable to type 'boolean'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts(8,5): error TS2418: Type of computed property's value is 'number', which is not assignable to type 'boolean'.
+tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts(6,5): error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
+  Index signatures are incompatible.
+    Type 'string | number' is not assignable to type 'boolean'.
+      Type 'string' is not assignable to type 'boolean'.
 
 
-==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts (2 errors) ====
+==== tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts (1 errors) ====
     interface I {
         [s: string]: boolean;
         [s: number]: boolean;
     }
 
     var o: I = {
+        ~
+!!! error TS2322: Type '{ [x: string]: string | number; }' is not assignable to type 'I'.
+!!! error TS2322:   Index signatures are incompatible.
+!!! error TS2322:     Type 'string | number' is not assignable to type 'boolean'.
+!!! error TS2322:       Type 'string' is not assignable to type 'boolean'.
         [""+"foo"]: "",
-        ~~~~~~~~~~
-!!! error TS2418: Type of computed property's value is 'string', which is not assignable to type 'boolean'.
-!!! related TS6501 tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts:2:5: The expected type comes from this index signature.
         [""+"bar"]: 0
-        ~~~~~~~~~~
-!!! error TS2418: Type of computed property's value is 'number', which is not assignable to type 'boolean'.
-!!! related TS6501 tests/cases/conformance/es6/computedProperties/computedPropertyNamesContextualType8_ES6.ts:2:5: The expected type comes from this index signature.
     }

tests/baselines/reference/definiteAssignmentOfDestructuredVariable.types

@@ -18,20 +18,20 @@ class C<T extends Options> {
 >method : () => void
 
         let { a, b } = this.foo;
->a : { [P in keyof T]: T[P]; }["a"]
->b : { [P in keyof T]: T[P]; }["b"]
+>a : T["a"]
+>b : T["b"]
 >this.foo : { [P in keyof T]: T[P]; }
 >this : this
 >foo : { [P in keyof T]: T[P]; }
 
         !(a && b);
 >!(a && b) : false
->(a && b) : { [P in keyof T]: T[P]; }["b"]
->a && b : { [P in keyof T]: T[P]; }["b"]
->a : { [P in keyof T]: T[P]; }["a"]
->b : { [P in keyof T]: T[P]; }["b"]
+>(a && b) : T["b"]
+>a && b : T["b"]
+>a : T["a"]
+>b : T["b"]
 
         a;
->a : { [P in keyof T]: T[P]; }["a"]
+>a : T["a"]
     }
 }

tests/baselines/reference/genericObjectRest.js

@@ -0,0 +1,61 @@
+//// [genericObjectRest.ts]
+const a = 'a';
+
+function f1<T extends { a: string, b: number }>(obj: T) {
+    let { ...r0 } = obj;
+    let { a: a1, ...r1 } = obj;
+    let { a: a2, b: b2, ...r2 } = obj;
+    let { 'a': a3, ...r3 } = obj;
+    let { ['a']: a4, ...r4 } = obj;
+    let { [a]: a5, ...r5 } = obj;
+}
+
+const sa = Symbol();
+const sb = Symbol();
+
+function f2<T extends { [sa]: string, [sb]: number }>(obj: T) {
+    let { [sa]: a1, [sb]: b1, ...r1 } = obj;
+}
+
+function f3<T, K1 extends keyof T, K2 extends keyof T>(obj: T, k1: K1, k2: K2) {
+    let { [k1]: a1, [k2]: a2, ...r1 } = obj;
+}
+
+type Item = { a: string, b: number, c: boolean };
+
+function f4<K1 extends keyof Item, K2 extends keyof Item>(obj: Item, k1: K1, k2: K2) {
+    let { [k1]: a1, [k2]: a2, ...r1 } = obj;
+}
+
+
+//// [genericObjectRest.js]
+"use strict";
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
+        t[p] = s[p];
+    if (s != null && typeof Object.getOwnPropertySymbols === "function")
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
+            t[p[i]] = s[p[i]];
+    return t;
+};
+const a = 'a';
+function f1(obj) {
+    let r0 = __rest(obj, []);
+    let { a: a1 } = obj, r1 = __rest(obj, ["a"]);
+    let { a: a2, b: b2 } = obj, r2 = __rest(obj, ["a", "b"]);
+    let { 'a': a3 } = obj, r3 = __rest(obj, ['a']);
+    let { ['a']: a4 } = obj, r4 = __rest(obj, ['a']);
+    let _a = a, a5 = obj[_a], r5 = __rest(obj, [typeof _a === "symbol" ? _a : _a + ""]);
+}
+const sa = Symbol();
+const sb = Symbol();
+function f2(obj) {
+    let _a = sa, a1 = obj[_a], _b = sb, b1 = obj[_b], r1 = __rest(obj, [typeof _a === "symbol" ? _a : _a + "", typeof _b === "symbol" ? _b : _b + ""]);
+}
+function f3(obj, k1, k2) {
+    let _a = k1, a1 = obj[_a], _b = k2, a2 = obj[_b], r1 = __rest(obj, [typeof _a === "symbol" ? _a : _a + "", typeof _b === "symbol" ? _b : _b + ""]);
+}
+function f4(obj, k1, k2) {
+    let _a = k1, a1 = obj[_a], _b = k2, a2 = obj[_b], r1 = __rest(obj, [typeof _a === "symbol" ? _a : _a + "", typeof _b === "symbol" ? _b : _b + ""]);
+}