Port remaining collision checks from checkCollisionsForDeclarationName

- Add checkCollisionWithGlobalPromiseInGeneratedCode for Promise collision detection
- Add recordPotentialCollisionWithReflectInGeneratedCode and checkReflectCollision for Reflect collision detection
- Add checkClassNameCollisionWithObject for Object class name collision detection
- Update checkCollisionsForDeclarationName to match TypeScript checker structure
- Add potentialReflectCollisions array to Checker struct
- Process Reflect collisions in checkSourceFile
- Accept updated baselines for new collision checks

Co-authored-by: jakebailey <[email protected]>

Author: Copilot

internal/checker/checker.go

@@ -775,6 +775,7 @@ type Checker struct {
 	flowNodeReachable                           map[*ast.FlowNode]bool
 	flowNodePostSuper                           map[*ast.FlowNode]bool
 	potentialWeakMapSetCollisions               []*ast.Node
+	potentialReflectCollisions                  []*ast.Node
 	renamedBindingElementsInTypes               []*ast.Node
 	contextualInfos                             []ContextualInfo
 	inferenceContextInfos                       []InferenceContextInfo
@@ -2128,6 +2129,7 @@ func (c *Checker) checkSourceFile(ctx context.Context, sourceFile *ast.SourceFil
 		c.checkGrammarSourceFile(sourceFile)
 		c.renamedBindingElementsInTypes = nil
 		c.potentialWeakMapSetCollisions = nil
+		c.potentialReflectCollisions = nil
 		c.checkSourceElements(sourceFile.Statements.Nodes)
 		c.checkDeferredNodes(sourceFile)
 		if ast.IsExternalOrCommonJSModule(sourceFile) {
@@ -2151,6 +2153,12 @@ func (c *Checker) checkSourceFile(ctx context.Context, sourceFile *ast.SourceFil
 			}
 			c.potentialWeakMapSetCollisions = nil
 		}
+		if len(c.potentialReflectCollisions) > 0 {
+			for _, node := range c.potentialReflectCollisions {
+				c.checkReflectCollision(node)
+			}
+			c.potentialReflectCollisions = nil
+		}
 		c.ctx = nil
 		links.typeChecked = true
 	}
@@ -10158,14 +10166,19 @@ func (c *Checker) assignBindingElementTypes(pattern *ast.Node, parentType *Type)
 }
 
 func (c *Checker) checkCollisionsForDeclarationName(node *ast.Node, name *ast.Node) {
+	if name == nil {
+		return
+	}
 	c.checkCollisionWithRequireExportsInGeneratedCode(node, name)
+	c.checkCollisionWithGlobalPromiseInGeneratedCode(node, name)
 	c.recordPotentialCollisionWithWeakMapSetInGeneratedCode(node, name)
-	switch {
-	case name == nil:
-		return
-	case ast.IsClassLike(node):
+	c.recordPotentialCollisionWithReflectInGeneratedCode(node, name)
+	if ast.IsClassLike(node) {
 		c.checkTypeNameIsReserved(name, diagnostics.Class_name_cannot_be_0)
-	case ast.IsEnumDeclaration(node):
+		if node.Flags&ast.NodeFlagsAmbient == 0 {
+			c.checkClassNameCollisionWithObject(name)
+		}
+	} else if ast.IsEnumDeclaration(node) {
 		c.checkTypeNameIsReserved(name, diagnostics.Enum_name_cannot_be_0)
 	}
 }
@@ -10248,6 +10261,66 @@ func (c *Checker) checkWeakMapSetCollision(node *ast.Node) {
 	}
 }
 
+func (c *Checker) checkCollisionWithGlobalPromiseInGeneratedCode(node *ast.Node, name *ast.Node) {
+	if name == nil || c.languageVersion >= core.ScriptTargetES2017 || !c.needCollisionCheckForIdentifier(node, name, "Promise") {
+		return
+	}
+	// Uninstantiated modules shouldn't do this check
+	if ast.IsModuleDeclaration(node) && ast.GetModuleInstanceState(node) != ast.ModuleInstanceStateInstantiated {
+		return
+	}
+	// In case of variable declaration, node.parent is variable statement so look at the variable statement's parent
+	parent := ast.GetDeclarationContainer(node)
+	// Note: TypeScript checks for HasAsyncFunctions flag, but since that flag is not yet ported to Go,
+	// we conservatively check all external/CommonJS modules. This may produce false positives
+	// but is safer than missing real issues.
+	if ast.IsSourceFile(parent) && ast.IsExternalOrCommonJSModule(parent.AsSourceFile()) {
+		// If the declaration happens to be in external module, report error that Promise is a reserved identifier.
+		c.errorSkippedOnNoEmit(name, diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_in_top_level_scope_of_a_module_containing_async_functions, scanner.DeclarationNameToString(name), scanner.DeclarationNameToString(name))
+	}
+}
+
+func (c *Checker) recordPotentialCollisionWithReflectInGeneratedCode(node *ast.Node, name *ast.Node) {
+	if name != nil && c.languageVersion <= core.ScriptTargetES2021 && c.needCollisionCheckForIdentifier(node, name, "Reflect") {
+		c.potentialReflectCollisions = append(c.potentialReflectCollisions, node)
+	}
+}
+
+func (c *Checker) checkReflectCollision(node *ast.Node) {
+	hasCollision := false
+	if ast.IsClassExpression(node) {
+		// ClassExpression names don't contribute to their containers, but do matter for any of their block-scoped members.
+		for _, member := range node.Members() {
+			if c.nodeLinks.Get(member).flags&NodeCheckFlagsContainsSuperPropertyInStaticInitializer != 0 {
+				hasCollision = true
+				break
+			}
+		}
+	} else if ast.IsFunctionExpression(node) {
+		// FunctionExpression names don't contribute to their containers, but do matter for their contents
+		if c.nodeLinks.Get(node).flags&NodeCheckFlagsContainsSuperPropertyInStaticInitializer != 0 {
+			hasCollision = true
+		}
+	} else {
+		container := ast.GetEnclosingBlockScopeContainer(node)
+		if container != nil && c.nodeLinks.Get(container).flags&NodeCheckFlagsContainsSuperPropertyInStaticInitializer != 0 {
+			hasCollision = true
+		}
+	}
+	if hasCollision {
+		name := node.Name()
+		if name != nil && ast.IsIdentifier(name) {
+			c.errorSkippedOnNoEmit(node, diagnostics.Duplicate_identifier_0_Compiler_reserves_name_1_when_emitting_super_references_in_static_initializers, scanner.DeclarationNameToString(name), "Reflect")
+		}
+	}
+}
+
+func (c *Checker) checkClassNameCollisionWithObject(name *ast.Node) {
+	if name.Text() == "Object" && c.program.GetEmitModuleFormatOfFile(ast.GetSourceFileOfNode(name)) < core.ModuleKindES2015 {
+		c.error(name, diagnostics.Class_name_cannot_be_Object_when_targeting_ES5_and_above_with_module_0, core.ModuleKind(c.moduleKind).String())
+	}
+}
+
 func (c *Checker) checkTypeOfExpression(node *ast.Node) *Type {
 	c.checkExpression(node.Expression())
 	return c.typeofType

testdata/baselines/reference/submodule/compiler/checkForObjectTooStrict.errors.txt

@@ -0,0 +1,37 @@
+checkForObjectTooStrict.ts(3,18): error TS2725: Class name cannot be 'Object' when targeting ES5 and above with module CommonJS.
+
+
+==== checkForObjectTooStrict.ts (1 errors) ====
+    module Foo {
+    
+        export class Object {
+                     ~~~~~~
+!!! error TS2725: Class name cannot be 'Object' when targeting ES5 and above with module CommonJS.
+    
+        }
+    
+    }
+    
+     
+    
+    class Bar extends Foo.Object { // should work
+    
+        constructor () {
+    
+            super();
+    
+        }
+    
+    }
+    
+    
+    class Baz extends Object {
+    
+        constructor () { // ERROR, as expected
+    
+            super();
+    
+        }
+    
+    }
+    

testdata/baselines/reference/submodule/compiler/checkForObjectTooStrict.errors.txt.diff

@@ -1,18 +1,21 @@
+instanceofOperator.ts(7,11): error TS2725: Class name cannot be 'Object' when targeting ES5 and above with module CommonJS.
 instanceofOperator.ts(12,5): error TS2358: The left-hand side of an 'instanceof' expression must be of type 'any', an object type or a type parameter.
 instanceofOperator.ts(15,20): error TS2359: The right-hand side of an 'instanceof' expression must be either of type 'any', a class, function, or other type assignable to the 'Function' interface type, or an object type with a 'Symbol.hasInstance' method.
 instanceofOperator.ts(16,23): error TS2359: The right-hand side of an 'instanceof' expression must be either of type 'any', a class, function, or other type assignable to the 'Function' interface type, or an object type with a 'Symbol.hasInstance' method.
 instanceofOperator.ts(19,5): error TS2358: The left-hand side of an 'instanceof' expression must be of type 'any', an object type or a type parameter.
 instanceofOperator.ts(21,5): error TS2358: The left-hand side of an 'instanceof' expression must be of type 'any', an object type or a type parameter.
 
 
-==== instanceofOperator.ts (5 errors) ====
+==== instanceofOperator.ts (6 errors) ====
     // Spec:
     // The instanceof operator requires the left operand to be of type Any or an object type, and the right 
     // operand to be of type Any or a subtype of the ‘Function’ interface type. The result is always of the 
     // Boolean primitive type.
 
     module test {
         class Object { }
+              ~~~~~~
+!!! error TS2725: Class name cannot be 'Object' when targeting ES5 and above with module CommonJS.
         var obj: Object;
 
 

testdata/baselines/reference/submodule/compiler/instanceofOperator.errors.txt

@@ -1,3 +1,4 @@
+moduleInTypePosition1_0.ts(1,14): error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
 moduleInTypePosition1_1.ts(3,14): error TS2709: Cannot use namespace 'WinJS' as a type.
 
 
@@ -8,8 +9,10 @@ moduleInTypePosition1_1.ts(3,14): error TS2709: Cannot use namespace 'WinJS' as
                  ~~~~~
 !!! error TS2709: Cannot use namespace 'WinJS' as a type.
 
-==== moduleInTypePosition1_0.ts (0 errors) ====
+==== moduleInTypePosition1_0.ts (1 errors) ====
     export class Promise {
+                 ~~~~~~~
+!!! error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
         foo: string;
     }
 

testdata/baselines/reference/submodule/compiler/instanceofOperator.errors.txt.diff

@@ -0,0 +1,19 @@
+--- old.moduleInTypePosition1.errors.txt
++++ new.moduleInTypePosition1.errors.txt
+@@= skipped -0, +0 lines =@@
++moduleInTypePosition1_0.ts(1,14): error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
+ moduleInTypePosition1_1.ts(3,14): error TS2709: Cannot use namespace 'WinJS' as a type.
+
+
+@@= skipped -7, +8 lines =@@
+                  ~~~~~
+ !!! error TS2709: Cannot use namespace 'WinJS' as a type.
+     
+-==== moduleInTypePosition1_0.ts (0 errors) ====
++==== moduleInTypePosition1_0.ts (1 errors) ====
+     export class Promise {
++                 ~~~~~~~
++!!! error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
+         foo: string;
+     }
+     

testdata/baselines/reference/submodule/compiler/moduleInTypePosition1.errors.txt

@@ -0,0 +1,16 @@
+staticInstanceResolution3_0.ts(1,14): error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
+
+
+==== staticInstanceResolution3_1.ts (0 errors) ====
+    ///<reference path='staticInstanceResolution3_0.ts'/>
+    import WinJS = require('./staticInstanceResolution3_0');
+    WinJS.Promise.timeout(10);
+==== staticInstanceResolution3_0.ts (1 errors) ====
+    export class Promise {
+                 ~~~~~~~
+!!! error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
+        static timeout(delay: number): Promise {
+            return null;
+        }
+    }
+    

testdata/baselines/reference/submodule/compiler/moduleInTypePosition1.errors.txt.diff

@@ -0,0 +1,20 @@
+--- old.staticInstanceResolution3.errors.txt
++++ new.staticInstanceResolution3.errors.txt
+@@= skipped -0, +0 lines =@@
+-<no content>
++staticInstanceResolution3_0.ts(1,14): error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
++
++
++==== staticInstanceResolution3_1.ts (0 errors) ====
++    ///<reference path='staticInstanceResolution3_0.ts'/>
++    import WinJS = require('./staticInstanceResolution3_0');
++    WinJS.Promise.timeout(10);
++==== staticInstanceResolution3_0.ts (1 errors) ====
++    export class Promise {
++                 ~~~~~~~
++!!! error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
++        static timeout(delay: number): Promise {
++            return null;
++        }
++    }
++    

testdata/baselines/reference/submodule/compiler/staticInstanceResolution3.errors.txt

@@ -1,3 +1,4 @@
+staticInstanceResolution5_0.ts(1,14): error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
 staticInstanceResolution5_1.ts(4,14): error TS2709: Cannot use namespace 'WinJS' as a type.
 staticInstanceResolution5_1.ts(5,23): error TS2709: Cannot use namespace 'WinJS' as a type.
 staticInstanceResolution5_1.ts(6,16): error TS2709: Cannot use namespace 'WinJS' as a type.
@@ -17,8 +18,10 @@ staticInstanceResolution5_1.ts(6,16): error TS2709: Cannot use namespace 'WinJS'
                    ~~~~~
 !!! error TS2709: Cannot use namespace 'WinJS' as a type.
 
-==== staticInstanceResolution5_0.ts (0 errors) ====
+==== staticInstanceResolution5_0.ts (1 errors) ====
     export class Promise {
+                 ~~~~~~~
+!!! error TS2529: Duplicate identifier 'Promise'. Compiler reserves name 'Promise' in top level scope of a module containing async functions.
         static timeout(delay: number): Promise {
             return null;
         }