Restore global

microsoft · jakebailey · Mar 11, 2024 · Feb 28, 2024 · Feb 28, 2024 · Feb 28, 2024
commit f8db7074ce3c63479343de81cc19f9e709ca122b
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -1473,7 +1473,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     var globals = createSymbolTable();
     var undefinedSymbol = createSymbol(SymbolFlags.Property, "undefined" as __String);
     undefinedSymbol.declarations = [];
-    globals.set(undefinedSymbol.escapedName, undefinedSymbol);
 
     var globalThisSymbol = createSymbol(SymbolFlags.Module, "globalThis" as __String, CheckFlags.Readonly);
     globalThisSymbol.exports = globals;
@@ -2256,6 +2255,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     var identityRelation = new Map<string, RelationComparisonResult>();
     var enumRelation = new Map<string, RelationComparisonResult>();
 
+    var builtinGlobals = createSymbolTable();
+    builtinGlobals.set(undefinedSymbol.escapedName, undefinedSymbol);
+
     // Extensions suggested for path imports when module resolution is node16 or higher.
     // The first element of each tuple is the extension a file has.
     // The second element of each tuple is the extension that should be used in a path import.
@@ -2718,6 +2720,23 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
     }
 
+    function addToSymbolTable(target: SymbolTable, source: SymbolTable, message: DiagnosticMessage) {
+        source.forEach((sourceSymbol, id) => {
+            const targetSymbol = target.get(id);
+            if (targetSymbol) {
+                // Error on redeclarations
+                forEach(targetSymbol.declarations, addDeclarationDiagnostic(unescapeLeadingUnderscores(id), message));
+            }
+            else {
+                target.set(id, sourceSymbol);
+            }
+        });
+
+        function addDeclarationDiagnostic(id: string, message: DiagnosticMessage) {
+            return (declaration: Declaration) => diagnostics.add(createDiagnosticForNode(declaration, message, id));
+        }
+    }
+
     function getSymbolLinks(symbol: Symbol): SymbolLinks {
         if (symbol.flags & SymbolFlags.Transient) return (symbol as TransientSymbol).links;
         const id = getSymbolId(symbol);
@@ -48777,6 +48796,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             }
         }
 
+        // Setup global builtins
+        addToSymbolTable(globals, builtinGlobals, Diagnostics.Declaration_name_conflicts_with_built_in_global_identifier_0);
+
         getSymbolLinks(undefinedSymbol).type = undefinedWideningType;
         getSymbolLinks(argumentsSymbol).type = getGlobalType("IArguments" as __String, /*arity*/ 0, /*reportErrors*/ true);
         getSymbolLinks(unknownSymbol).type = errorType;

diff --git a/tests/baselines/reference/mappedTypeRecursiveInference.types b/tests/baselines/reference/mappedTypeRecursiveInference.types
diff --git a/tests/baselines/reference/undefinedTypeAssignment1.errors.txt b/tests/baselines/reference/undefinedTypeAssignment1.errors.txt
@@ -1,9 +1,12 @@
+undefinedTypeAssignment1.ts(1,6): error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 undefinedTypeAssignment1.ts(1,6): error TS2457: Type alias name cannot be 'undefined'.
 
 
-==== undefinedTypeAssignment1.ts (1 errors) ====
+==== undefinedTypeAssignment1.ts (2 errors) ====
     type undefined = string;
          ~~~~~~~~~
+!!! error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
+         ~~~~~~~~~
 !!! error TS2457: Type alias name cannot be 'undefined'.
     function p(undefined = "wat") {
     	return undefined;

diff --git a/tests/baselines/reference/undefinedTypeAssignment2.errors.txt b/tests/baselines/reference/undefinedTypeAssignment2.errors.txt
@@ -1,8 +1,8 @@
-undefinedTypeAssignment2.ts(1,5): error TS2300: Duplicate identifier 'undefined'.
+undefinedTypeAssignment2.ts(1,5): error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 
 
 ==== undefinedTypeAssignment2.ts (1 errors) ====
     var undefined = void 0;
         ~~~~~~~~~
-!!! error TS2300: Duplicate identifier 'undefined'.
+!!! error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 
diff --git a/tests/baselines/reference/undefinedTypeAssignment3.errors.txt b/tests/baselines/reference/undefinedTypeAssignment3.errors.txt
@@ -1,8 +1,8 @@
-undefinedTypeAssignment3.ts(1,5): error TS2300: Duplicate identifier 'undefined'.
+undefinedTypeAssignment3.ts(1,5): error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 
 
 ==== undefinedTypeAssignment3.ts (1 errors) ====
     var undefined = null;
         ~~~~~~~~~
-!!! error TS2300: Duplicate identifier 'undefined'.
+!!! error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 
diff --git a/tests/baselines/reference/undefinedTypeAssignment4.errors.txt b/tests/baselines/reference/undefinedTypeAssignment4.errors.txt
@@ -1,28 +1,28 @@
-undefinedTypeAssignment4.ts(1,7): error TS2300: Duplicate identifier 'undefined'.
+undefinedTypeAssignment4.ts(1,7): error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 undefinedTypeAssignment4.ts(1,7): error TS2414: Class name cannot be 'undefined'.
-undefinedTypeAssignment4.ts(4,11): error TS2300: Duplicate identifier 'undefined'.
+undefinedTypeAssignment4.ts(4,11): error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 undefinedTypeAssignment4.ts(4,11): error TS2427: Interface name cannot be 'undefined'.
-undefinedTypeAssignment4.ts(7,11): error TS2300: Duplicate identifier 'undefined'.
+undefinedTypeAssignment4.ts(7,11): error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
 
 
 ==== undefinedTypeAssignment4.ts (5 errors) ====
     class undefined {
           ~~~~~~~~~
-!!! error TS2300: Duplicate identifier 'undefined'.
+!!! error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
           ~~~~~~~~~
 !!! error TS2414: Class name cannot be 'undefined'.
     	foo: string;
     }
     interface undefined {
               ~~~~~~~~~
-!!! error TS2300: Duplicate identifier 'undefined'.
+!!! error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
               ~~~~~~~~~
 !!! error TS2427: Interface name cannot be 'undefined'.
     	member: number;
     }
     namespace undefined {
               ~~~~~~~~~
-!!! error TS2300: Duplicate identifier 'undefined'.
+!!! error TS2397: Declaration name conflicts with built-in global identifier 'undefined'.
     	export var x = 42;
     }
     var x: undefined;

diff --git a/tests/baselines/reference/undefinedTypeAssignment4.symbols b/tests/baselines/reference/undefinedTypeAssignment4.symbols
@@ -24,5 +24,5 @@ var x: undefined;
 
 var y: typeof undefined;
 >y : Symbol(y, Decl(undefinedTypeAssignment4.ts, 10, 3))
->undefined : Symbol(undefined)
+>undefined : Symbol(undefined, Decl(undefinedTypeAssignment4.ts, 0, 0), Decl(undefinedTypeAssignment4.ts, 2, 1), Decl(undefinedTypeAssignment4.ts, 5, 1))
 
diff --git a/tests/baselines/reference/undefinedTypeAssignment4.types b/tests/baselines/reference/undefinedTypeAssignment4.types
@@ -22,6 +22,6 @@ var x: undefined;
 >x : undefined
 
 var y: typeof undefined;
->y : any
->undefined : undefined
+>y : typeof undefined
+>undefined : typeof undefined