Merge branch 'master' into fix39364

# Conflicts:
#	src/compiler/checker.ts

Author: ahejlsberg

CONTRIBUTING.md

@@ -63,7 +63,7 @@ TypeScript is currently accepting contributions in the form of bug fixes. A bug
 
 ## Contributing features
 
-Features (things that add new or improved functionality to TypeScript) may be accepted, but will need to first be approved (labelled ["help wanted"](https://github.com/Microsoft/TypeScript/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+wanted%22) or in the "Backlog" milestone) by a TypeScript project maintainer) in the suggestion issue. Features with language design impact, or that are adequately satisfied with external tools, will not be accepted.
+Features (things that add new or improved functionality to TypeScript) may be accepted, but will need to first be approved (labelled ["help wanted"](https://github.com/Microsoft/TypeScript/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+wanted%22) or in the "Backlog" milestone) by a TypeScript project maintainer in the suggestion issue. Features with language design impact, or that are adequately satisfied with external tools, will not be accepted.
 
 Design changes will not be accepted at this time. If you have a design change proposal, please log a suggestion issue.
 

src/compat/deprecations.ts

@@ -1321,4 +1321,24 @@ namespace ts {
     });
 
     // #endregion Renamed node Tests
+
+    // DEPRECATION: Renamed `Map` and `ReadonlyMap` interfaces
+    // DEPRECATION PLAN:
+    //     - soft: 4.0
+    //     - remove: TBD (will remove for at least one release before replacing with `ESMap`/`ReadonlyESMap`)
+    //     - replace: TBD (will eventually replace with `ESMap`/`ReadonlyESMap`)
+    // #region Renamed `Map` and `ReadonlyMap` interfaces
+
+    /**
+     * @deprecated Use `ts.ReadonlyESMap<K, V>` instead.
+     */
+    export interface ReadonlyMap<T> extends ReadonlyESMap<string, T> {
+    }
+
+    /**
+     * @deprecated Use `ts.ESMap<K, V>` instead.
+     */
+    export interface Map<T> extends ESMap<string, T> { }
+
+    // #endregion
 }

src/compiler/binder.ts

@@ -218,7 +218,7 @@ namespace ts {
         let symbolCount = 0;
 
         let Symbol: new (flags: SymbolFlags, name: __String) => Symbol;
-        let classifiableNames: UnderscoreEscapedMap<true>;
+        let classifiableNames: Set<__String>;
 
         const unreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
         const reportedUnreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
@@ -237,7 +237,7 @@ namespace ts {
             options = opts;
             languageVersion = getEmitScriptTarget(options);
             inStrictMode = bindInStrictMode(file, opts);
-            classifiableNames = createUnderscoreEscapedMap<true>();
+            classifiableNames = new Set();
             symbolCount = 0;
 
             Symbol = objectAllocator.getSymbolConstructor();
@@ -445,7 +445,7 @@ namespace ts {
                 symbol = symbolTable.get(name);
 
                 if (includes & SymbolFlags.Classifiable) {
-                    classifiableNames.set(name, true);
+                    classifiableNames.add(name);
                 }
 
                 if (!symbol) {
@@ -1965,7 +1965,7 @@ namespace ts {
             }
 
             if (inStrictMode && !isAssignmentTarget(node)) {
-                const seen = createUnderscoreEscapedMap<ElementKind>();
+                const seen = new Map<__String, ElementKind>();
 
                 for (const prop of node.properties) {
                     if (prop.kind === SyntaxKind.SpreadAssignment || prop.name.kind !== SyntaxKind.Identifier) {
@@ -2980,6 +2980,9 @@ namespace ts {
         }
 
         function bindPotentiallyMissingNamespaces(namespaceSymbol: Symbol | undefined, entityName: BindableStaticNameExpression, isToplevel: boolean, isPrototypeProperty: boolean, containerIsClass: boolean) {
+            if (namespaceSymbol?.flags! & SymbolFlags.Alias) {
+                return namespaceSymbol;
+            }
             if (isToplevel && !isPrototypeProperty) {
                 // make symbols or add declarations for intermediate containers
                 const flags = SymbolFlags.Module | SymbolFlags.Assignment;
@@ -3143,7 +3146,7 @@ namespace ts {
                 bindAnonymousDeclaration(node, SymbolFlags.Class, bindingName);
                 // Add name of class expression into the map for semantic classifier
                 if (node.name) {
-                    classifiableNames.set(node.name.escapedText, true);
+                    classifiableNames.add(node.name.escapedText);
                 }
             }