Only error on non-ambient instantiated modules preceding clodules.

Author: DanielRosenwasser

src/compiler/checker.ts

@@ -9003,7 +9003,12 @@ module ts {
                 checkCollisionWithRequireExportsInGeneratedCode(node, node.name);
                 checkExportsOnMergedDeclarations(node);
                 var symbol = getSymbolOfNode(node);
-                if (symbol.flags & SymbolFlags.ValueModule && symbol.declarations.length > 1 && !isInAmbientContext(node)) {
+
+                // The following checks only apply on a non-ambient instantiated module declaration.
+                if (symbol.flags & SymbolFlags.ValueModule
+                    && symbol.declarations.length > 1
+                    && !isInAmbientContext(node)
+                    && isInstantiatedModule(node, compilerOptions.preserveConstEnums)) {
                     var classOrFunc = getFirstNonAmbientClassOrFunctionDeclaration(symbol);
                     if (classOrFunc) {
                         if (getSourceFileOfNode(node) !== getSourceFileOfNode(classOrFunc)) {
@@ -9014,6 +9019,8 @@ module ts {
                         }
                     }
                 }
+
+                // Checks for ambient external modules.
                 if (node.name.kind === SyntaxKind.StringLiteral) {
                     if (!isGlobalSourceFile(node.parent)) {
                         error(node.name, Diagnostics.Ambient_external_modules_cannot_be_nested_in_other_modules);

src/compiler/emitter.ts

@@ -3680,8 +3680,8 @@ module ts {
             }
 
             function emitModuleDeclaration(node: ModuleDeclaration) {
-                var shouldEmit = getModuleInstanceState(node) === ModuleInstanceState.Instantiated ||
-                    (getModuleInstanceState(node) === ModuleInstanceState.ConstEnumOnly && compilerOptions.preserveConstEnums);
+                // Emit only if this module is non-ambient.
+                var shouldEmit = isInstantiatedModule(node, compilerOptions.preserveConstEnums);
 
                 if (!shouldEmit) {
                     return emitPinnedOrTripleSlashComments(node);

src/compiler/utilities.ts

@@ -525,6 +525,12 @@ module ts {
         return false;
     }
 
+    export function isInstantiatedModule(node: ModuleDeclaration, preserveConstEnums: boolean) {
+        var moduleState = getModuleInstanceState(node)
+        return moduleState === ModuleInstanceState.Instantiated ||
+               (preserveConstEnums && moduleState === ModuleInstanceState.ConstEnumOnly);
+    }
+
     export function isExternalModuleImportDeclaration(node: Node) {
         return node.kind === SyntaxKind.ImportDeclaration && (<ImportDeclaration>node).moduleReference.kind === SyntaxKind.ExternalModuleReference;
     }

tests/baselines/reference/cloduleWithPriorUninstantiatedModule.errors.txt

@@ -0,0 +1,25 @@
+=== tests/cases/compiler/cloduleWithPriorUninstantiatedModule.ts ===
+// Ambient/uninstantiated module.
+module Moclodule {
+>Moclodule : typeof Moclodule
+
+    export interface Someinterface {
+>Someinterface : Someinterface
+
+        foo(): void;
+>foo : () => void
+    }
+}
+
+class Moclodule {
+>Moclodule : Moclodule
+}
+
+// Instantiated module.
+module Moclodule {
+>Moclodule : typeof Moclodule
+
+    export class Manager {
+>Manager : Manager
+    }
+}