A shorthand ambient module should be considered as possibly exporting a value.

Author: Andy Hanson

src/compiler/checker.ts

@@ -1043,7 +1043,7 @@ namespace ts {
             const moduleSymbol = resolveExternalModuleName(node, (<ImportDeclaration>node.parent).moduleSpecifier);
 
             if (moduleSymbol) {
-                const exportDefaultSymbol = isShorthandAmbientModule(moduleSymbol.valueDeclaration) ?
+                const exportDefaultSymbol = isShorthandAmbientModuleSymbol(moduleSymbol) ?
                     moduleSymbol :
                     moduleSymbol.exports["export="] ?
                         getPropertyOfType(getTypeOfSymbol(moduleSymbol.exports["export="]), "default") :
@@ -1119,7 +1119,7 @@ namespace ts {
             if (targetSymbol) {
                 const name = specifier.propertyName || specifier.name;
                 if (name.text) {
-                    if (isShorthandAmbientModule(moduleSymbol.valueDeclaration)) {
+                    if (isShorthandAmbientModuleSymbol(moduleSymbol)) {
                         return moduleSymbol;
                     }
 
@@ -3381,7 +3381,7 @@ namespace ts {
         function getTypeOfFuncClassEnumModule(symbol: Symbol): Type {
             const links = getSymbolLinks(symbol);
             if (!links.type) {
-                if (symbol.valueDeclaration.kind === SyntaxKind.ModuleDeclaration && isShorthandAmbientModule(<ModuleDeclaration>symbol.valueDeclaration)) {
+                if (symbol.valueDeclaration.kind === SyntaxKind.ModuleDeclaration && isShorthandAmbientModuleSymbol(symbol)) {
                     links.type = anyType;
                 }
                 else {
@@ -18365,8 +18365,8 @@ namespace ts {
 
         function moduleExportsSomeValue(moduleReferenceExpression: Expression): boolean {
             let moduleSymbol = resolveExternalModuleName(moduleReferenceExpression.parent, moduleReferenceExpression);
-            if (!moduleSymbol) {
-                // module not found - be conservative
+            if (!moduleSymbol || isShorthandAmbientModuleSymbol(moduleSymbol)) {
+                // If the module is not found or is shorthand, assume that it may export a value.
                 return true;
             }
 

src/compiler/utilities.ts

@@ -414,7 +414,11 @@ namespace ts {
             ((<ModuleDeclaration>node).name.kind === SyntaxKind.StringLiteral || isGlobalScopeAugmentation(<ModuleDeclaration>node));
     }
 
-    export function isShorthandAmbientModule(node: Node): boolean {
+    export function isShorthandAmbientModuleSymbol(moduleSymbol: Symbol): boolean {
+        return isShorthandAmbientModule(moduleSymbol.valueDeclaration);
+    }
+
+    function isShorthandAmbientModule(node: Node): boolean {
         // The only kind of module that can be missing a body is a shorthand ambient module.
         return node.kind === SyntaxKind.ModuleDeclaration && (!(<ModuleDeclaration>node).body);
     }

tests/baselines/reference/ambientShorthand_reExport.js

@@ -22,6 +22,10 @@ var jquery_1 = require("jquery");
 exports.x = jquery_1.x;
 //// [reExportAll.js]
 "use strict";
+function __export(m) {
+    for (var p in m) if (!exports.hasOwnProperty(p)) exports[p] = m[p];
+}
+__export(require("jquery"));
 //// [reExportUser.js]
 "use strict";
 var reExportX_1 = require("./reExportX");