Merge pull request #5343 from Microsoft/fixES6LetInModule

Fixes emitExpressionIdentifier when combining --target ES6 with --module.

Author: rbuckton

src/compiler/emitter.ts

@@ -1769,34 +1769,39 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                         write(".");
                     }
                 }
-                else if (modulekind !== ModuleKind.ES6) {
-                    let declaration = resolver.getReferencedImportDeclaration(node);
-                    if (declaration) {
-                        if (declaration.kind === SyntaxKind.ImportClause) {
-                            // Identifier references default import
-                            write(getGeneratedNameForNode(<ImportDeclaration>declaration.parent));
-                            write(languageVersion === ScriptTarget.ES3 ? "[\"default\"]" : ".default");
-                            return;
-                        }
-                        else if (declaration.kind === SyntaxKind.ImportSpecifier) {
-                            // Identifier references named import
-                            write(getGeneratedNameForNode(<ImportDeclaration>declaration.parent.parent.parent));
-                            let name =  (<ImportSpecifier>declaration).propertyName || (<ImportSpecifier>declaration).name;
-                            let identifier = getSourceTextOfNodeFromSourceFile(currentSourceFile, name);
-                            if (languageVersion === ScriptTarget.ES3 && identifier === "default") {
-                                write(`["default"]`);
+                else {
+                    if (modulekind !== ModuleKind.ES6) {
+                        let declaration = resolver.getReferencedImportDeclaration(node);
+                        if (declaration) {
+                            if (declaration.kind === SyntaxKind.ImportClause) {
+                                // Identifier references default import
+                                write(getGeneratedNameForNode(<ImportDeclaration>declaration.parent));
+                                write(languageVersion === ScriptTarget.ES3 ? "[\"default\"]" : ".default");
+                                return;
                             }
-                            else {
-                                write(".");
-                                write(identifier);
+                            else if (declaration.kind === SyntaxKind.ImportSpecifier) {
+                                // Identifier references named import
+                                write(getGeneratedNameForNode(<ImportDeclaration>declaration.parent.parent.parent));
+                                let name =  (<ImportSpecifier>declaration).propertyName || (<ImportSpecifier>declaration).name;
+                                let identifier = getSourceTextOfNodeFromSourceFile(currentSourceFile, name);
+                                if (languageVersion === ScriptTarget.ES3 && identifier === "default") {
+                                    write(`["default"]`);
+                                }
+                                else {
+                                    write(".");
+                                    write(identifier);
+                                }
+                                return;
                             }
-                            return;
                         }
                     }
-                    declaration = resolver.getReferencedNestedRedeclaration(node);
-                    if (declaration) {
-                        write(getGeneratedNameForNode(declaration.name));
-                        return;
+
+                    if (languageVersion !== ScriptTarget.ES6) {
+                        let declaration = resolver.getReferencedNestedRedeclaration(node);
+                        if (declaration) {
+                            write(getGeneratedNameForNode(declaration.name));
+                            return;
+                        }
                     }
                 }
 
@@ -2785,7 +2790,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
 
             /**
              * Emit ES7 exponentiation operator downlevel using Math.pow
-             * @param node a binary expression node containing exponentiationOperator (**, **=) 
+             * @param node a binary expression node containing exponentiationOperator (**, **=)
              */
             function emitExponentiationOperator(node: BinaryExpression) {
                 let leftHandSideExpression = node.left;

tests/baselines/reference/nestedRedeclarationInES6AMD.js

@@ -0,0 +1,15 @@
+//// [nestedRedeclarationInES6AMD.ts]
+function a() {
+    {
+        let status = 1;
+        status = 2;
+    }
+}
+
+//// [nestedRedeclarationInES6AMD.js]
+function a() {
+    {
+        let status = 1;
+        status = 2;
+    }
+}

tests/baselines/reference/nestedRedeclarationInES6AMD.symbols

@@ -0,0 +1,11 @@
+=== tests/cases/compiler/nestedRedeclarationInES6AMD.ts ===
+function a() {
+>a : Symbol(a, Decl(nestedRedeclarationInES6AMD.ts, 0, 0))
+    {
+        let status = 1;
+>status : Symbol(status, Decl(nestedRedeclarationInES6AMD.ts, 2, 11))
+
+        status = 2;
+>status : Symbol(status, Decl(nestedRedeclarationInES6AMD.ts, 2, 11))
+    }
+}

tests/baselines/reference/nestedRedeclarationInES6AMD.types

@@ -0,0 +1,14 @@
+=== tests/cases/compiler/nestedRedeclarationInES6AMD.ts ===
+function a() {
+>a : () => void
+    {
+        let status = 1;
+>status : number
+>1 : number
+
+        status = 2;
+>status = 2 : number
+>status : number
+>2 : number
+    }
+}

tests/cases/compiler/nestedRedeclarationInES6AMD.ts

@@ -0,0 +1,8 @@
+// @target: ES6
+// @module: AMD
+function a() {
+    {
+        let status = 1;
+        status = 2;
+    }
+}