Merge pull request #4355 from DavidSouther/ts4354

Emits safe value for import.

src/compiler/utilities.ts

@@ -240,7 +240,7 @@ namespace ts {
     // Make an identifier from an external module name by extracting the string after the last "/" and replacing
     // all non-alphanumeric characters with underscores
     export function makeIdentifierFromModuleName(moduleName: string): string {
-        return getBaseFileName(moduleName).replace(/\W/g, "_");
+        return getBaseFileName(moduleName).replace(/^(\d)/, "_$1").replace(/\W/g, "_");
     }
 
     export function isBlockOrCatchScoped(declaration: Declaration) {

tests/baselines/reference/commonjsSafeImport.js

@@ -0,0 +1,23 @@
+//// [tests/cases/compiler/commonjsSafeImport.ts] ////
+
+//// [10_lib.ts]
+
+export function Foo() {}
+
+//// [main.ts]
+import { Foo } from './10_lib';
+
+Foo();
+
+
+//// [10_lib.js]
+function Foo() { }
+exports.Foo = Foo;
+//// [main.js]
+var _10_lib_1 = require('./10_lib');
+_10_lib_1.Foo();
+
+
+//// [10_lib.d.ts]
+export declare function Foo(): void;
+//// [main.d.ts]

tests/baselines/reference/commonjsSafeImport.symbols

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/10_lib.ts ===
+
+export function Foo() {}
+>Foo : Symbol(Foo, Decl(10_lib.ts, 0, 0))
+
+=== tests/cases/compiler/main.ts ===
+import { Foo } from './10_lib';
+>Foo : Symbol(Foo, Decl(main.ts, 0, 8))
+
+Foo();
+>Foo : Symbol(Foo, Decl(main.ts, 0, 8))
+

tests/baselines/reference/commonjsSafeImport.types

@@ -0,0 +1,13 @@
+=== tests/cases/compiler/10_lib.ts ===
+
+export function Foo() {}
+>Foo : () => void
+
+=== tests/cases/compiler/main.ts ===
+import { Foo } from './10_lib';
+>Foo : () => void
+
+Foo();
+>Foo() : void
+>Foo : () => void
+

tests/cases/compiler/commonjsSafeImport.ts

@@ -0,0 +1,11 @@
+// @target: ES5
+// @module: commonjs
+// @declaration: true
+// @filename: 10_lib.ts
+
+export function Foo() {}
+
+// @filename: main.ts
+import { Foo } from './10_lib';
+
+Foo();