Do not treat local resolution of require call as external module

src/compiler/binder.ts

@@ -2072,7 +2072,9 @@ namespace ts {
         function setCommonJsModuleIndicator(node: Node) {
             if (!file.commonJsModuleIndicator) {
                 file.commonJsModuleIndicator = node;
-                bindSourceFileAsExternalModule();
+                if (!file.externalModuleIndicator) {
+                    bindSourceFileAsExternalModule();
+                }
             }
         }
 

src/compiler/checker.ts

@@ -12791,7 +12791,10 @@ namespace ts {
             }
 
             // In JavaScript files, calls to any identifier 'require' are treated as external module imports
-            if (isInJavaScriptFile(node) && isRequireCall(node, /*checkArgumentIsStringLiteral*/true)) {
+            if (isInJavaScriptFile(node) &&
+                isRequireCall(node, /*checkArgumentIsStringLiteral*/true) &&
+                // Make sure require is not a local function
+                !resolveName(node.expression, (<Identifier>node.expression).text, SymbolFlags.Value, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined)) {
                 return resolveExternalModuleTypeByLiteral(<StringLiteral>node.arguments[0]);
             }
 

tests/baselines/reference/requireAsFunctionInExternalModule.js

@@ -0,0 +1,37 @@
+//// [tests/cases/compiler/requireAsFunctionInExternalModule.ts] ////
+
+//// [c.js]
+export default function require(a) { }
+export function has(a) { return true }
+
+//// [m.js]
+import require, { has } from "./c"
+export function hello() { }
+if (has('ember-debug')) {
+    require('ember-debug');
+}
+
+//// [m2.ts]
+import { hello } from "./m";
+hello();
+
+
+//// [c.js]
+"use strict";
+function require(a) { }
+exports.__esModule = true;
+exports["default"] = require;
+function has(a) { return true; }
+exports.has = has;
+//// [m.js]
+"use strict";
+var c_1 = require("./c");
+function hello() { }
+exports.hello = hello;
+if (c_1.has('ember-debug')) {
+    c_1["default"]('ember-debug');
+}
+//// [m2.js]
+"use strict";
+var m_1 = require("./m");
+m_1.hello();

tests/baselines/reference/requireAsFunctionInExternalModule.symbols

@@ -0,0 +1,31 @@
+=== tests/cases/compiler/c.js ===
+export default function require(a) { }
+>require : Symbol(require, Decl(c.js, 0, 0))
+>a : Symbol(a, Decl(c.js, 0, 32))
+
+export function has(a) { return true }
+>has : Symbol(has, Decl(c.js, 0, 38))
+>a : Symbol(a, Decl(c.js, 1, 20))
+
+=== tests/cases/compiler/m.js ===
+import require, { has } from "./c"
+>require : Symbol(require, Decl(m.js, 0, 6))
+>has : Symbol(has, Decl(m.js, 0, 17))
+
+export function hello() { }
+>hello : Symbol(hello, Decl(m.js, 0, 34))
+
+if (has('ember-debug')) {
+>has : Symbol(has, Decl(m.js, 0, 17))
+
+    require('ember-debug');
+>require : Symbol(require, Decl(m.js, 0, 6))
+}
+
+=== tests/cases/compiler/m2.ts ===
+import { hello } from "./m";
+>hello : Symbol(hello, Decl(m2.ts, 0, 8))
+
+hello();
+>hello : Symbol(hello, Decl(m2.ts, 0, 8))
+

tests/baselines/reference/requireAsFunctionInExternalModule.types

@@ -0,0 +1,37 @@
+=== tests/cases/compiler/c.js ===
+export default function require(a) { }
+>require : (a: any) => void
+>a : any
+
+export function has(a) { return true }
+>has : (a: any) => boolean
+>a : any
+>true : true
+
+=== tests/cases/compiler/m.js ===
+import require, { has } from "./c"
+>require : (a: any) => void
+>has : (a: any) => boolean
+
+export function hello() { }
+>hello : () => void
+
+if (has('ember-debug')) {
+>has('ember-debug') : boolean
+>has : (a: any) => boolean
+>'ember-debug' : "ember-debug"
+
+    require('ember-debug');
+>require('ember-debug') : void
+>require : (a: any) => void
+>'ember-debug' : "ember-debug"
+}
+
+=== tests/cases/compiler/m2.ts ===
+import { hello } from "./m";
+>hello : () => void
+
+hello();
+>hello() : void
+>hello : () => void
+

tests/cases/compiler/requireAsFunctionInExternalModule.ts

@@ -0,0 +1,16 @@
+// @allowjs: true
+// @outDir: dist
+// @Filename: c.js
+export default function require(a) { }
+export function has(a) { return true }
+
+// @Filename: m.js
+import require, { has } from "./c"
+export function hello() { }
+if (has('ember-debug')) {
+    require('ember-debug');
+}
+
+// @Filename: m2.ts
+import { hello } from "./m";
+hello();