diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 65768332360..813a7e2cd43 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -130,7 +130,9 @@ namespace ts {
                 symbol.members = {};
             }
 
-            if (symbolFlags & SymbolFlags.Value && !symbol.valueDeclaration) {
+            if (symbolFlags & SymbolFlags.Value &&
+                (!symbol.valueDeclaration || symbol.valueDeclaration.kind === SyntaxKind.ModuleDeclaration)) {
+                // other kinds of value declarations take precedence over modules
                 symbol.valueDeclaration = node;
             }
         }
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6c233a57ef4..d22266d951f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -293,7 +293,11 @@ namespace ts {
                     target.constEnumOnlyModule = false;
                 }
                 target.flags |= source.flags;
-                if (!target.valueDeclaration && source.valueDeclaration) target.valueDeclaration = source.valueDeclaration;
+                if (source.valueDeclaration &&
+                    (!target.valueDeclaration || target.valueDeclaration.kind === SyntaxKind.ModuleDeclaration)) {
+                    // other kinds of value declarations take precedence over modules
+                    target.valueDeclaration = source.valueDeclaration;
+                }
                 forEach(source.declarations, node => {
                     target.declarations.push(node);
                 });
@@ -2766,9 +2770,7 @@ namespace ts {
         }
 
         function getBaseTypeNodeOfClass(type: InterfaceType): ExpressionWithTypeArguments {
-            let classDeclaration =
-                getDeclarationOfKind(type.symbol, SyntaxKind.ClassDeclaration) || type.symbol.valueDeclaration;
-            return getClassExtendsHeritageClauseElement(classDeclaration as ClassLikeDeclaration);
+            return getClassExtendsHeritageClauseElement(<ClassLikeDeclaration>type.symbol.valueDeclaration);
         }
 
         function getConstructorsForTypeArguments(type: ObjectType, typeArgumentNodes: TypeNode[]): Signature[] {
diff --git a/tests/baselines/reference/ambientClassDeclarationWithExtends.js b/tests/baselines/reference/ambientClassDeclarationWithExtends.js
index 5a31486bcf0..940efb8899f 100644
--- a/tests/baselines/reference/ambientClassDeclarationWithExtends.js
+++ b/tests/baselines/reference/ambientClassDeclarationWithExtends.js
@@ -1,4 +1,6 @@
-//// [ambientClassDeclarationWithExtends.ts]
+//// [tests/cases/compiler/ambientClassDeclarationWithExtends.ts] ////
+
+//// [ambientClassDeclarationExtends_singleFile.ts]
 declare class A { }
 declare class B extends A { }
 
@@ -10,10 +12,29 @@ declare class D extends C { }
 
 var d: C = new D();
 
+//// [ambientClassDeclarationExtends_file1.ts]
+
+declare class E {
+    public bar;
+}
+namespace F { var y; }
 
-//// [ambientClassDeclarationWithExtends.js]
+//// [ambientClassDeclarationExtends_file2.ts]
+
+declare class F extends E { }
+var f: E = new F();
+
+
+//// [ambientClassDeclarationExtends_singleFile.js]
 var D;
 (function (D) {
     var x;
 })(D || (D = {}));
 var d = new D();
+//// [ambientClassDeclarationExtends_file1.js]
+var F;
+(function (F) {
+    var y;
+})(F || (F = {}));
+//// [ambientClassDeclarationExtends_file2.js]
+var f = new F();
diff --git a/tests/baselines/reference/ambientClassDeclarationWithExtends.symbols b/tests/baselines/reference/ambientClassDeclarationWithExtends.symbols
index ba678910a9c..023ae6bf582 100644
--- a/tests/baselines/reference/ambientClassDeclarationWithExtends.symbols
+++ b/tests/baselines/reference/ambientClassDeclarationWithExtends.symbols
@@ -1,27 +1,50 @@
-=== tests/cases/compiler/ambientClassDeclarationWithExtends.ts ===
+=== tests/cases/compiler/ambientClassDeclarationExtends_singleFile.ts ===
 declare class A { }
->A : Symbol(A, Decl(ambientClassDeclarationWithExtends.ts, 0, 0))
+>A : Symbol(A, Decl(ambientClassDeclarationExtends_singleFile.ts, 0, 0))
 
 declare class B extends A { }
->B : Symbol(B, Decl(ambientClassDeclarationWithExtends.ts, 0, 19))
->A : Symbol(A, Decl(ambientClassDeclarationWithExtends.ts, 0, 0))
+>B : Symbol(B, Decl(ambientClassDeclarationExtends_singleFile.ts, 0, 19))
+>A : Symbol(A, Decl(ambientClassDeclarationExtends_singleFile.ts, 0, 0))
 
 declare class C {
->C : Symbol(C, Decl(ambientClassDeclarationWithExtends.ts, 1, 29))
+>C : Symbol(C, Decl(ambientClassDeclarationExtends_singleFile.ts, 1, 29))
 
     public foo;
->foo : Symbol(foo, Decl(ambientClassDeclarationWithExtends.ts, 3, 17))
+>foo : Symbol(foo, Decl(ambientClassDeclarationExtends_singleFile.ts, 3, 17))
 }
 namespace D { var x; }
->D : Symbol(D, Decl(ambientClassDeclarationWithExtends.ts, 5, 1), Decl(ambientClassDeclarationWithExtends.ts, 6, 22))
->x : Symbol(x, Decl(ambientClassDeclarationWithExtends.ts, 6, 17))
+>D : Symbol(D, Decl(ambientClassDeclarationExtends_singleFile.ts, 5, 1), Decl(ambientClassDeclarationExtends_singleFile.ts, 6, 22))
+>x : Symbol(x, Decl(ambientClassDeclarationExtends_singleFile.ts, 6, 17))
 
 declare class D extends C { }
->D : Symbol(D, Decl(ambientClassDeclarationWithExtends.ts, 5, 1), Decl(ambientClassDeclarationWithExtends.ts, 6, 22))
->C : Symbol(C, Decl(ambientClassDeclarationWithExtends.ts, 1, 29))
+>D : Symbol(D, Decl(ambientClassDeclarationExtends_singleFile.ts, 5, 1), Decl(ambientClassDeclarationExtends_singleFile.ts, 6, 22))
+>C : Symbol(C, Decl(ambientClassDeclarationExtends_singleFile.ts, 1, 29))
 
 var d: C = new D();
->d : Symbol(d, Decl(ambientClassDeclarationWithExtends.ts, 9, 3))
->C : Symbol(C, Decl(ambientClassDeclarationWithExtends.ts, 1, 29))
->D : Symbol(D, Decl(ambientClassDeclarationWithExtends.ts, 5, 1), Decl(ambientClassDeclarationWithExtends.ts, 6, 22))
+>d : Symbol(d, Decl(ambientClassDeclarationExtends_singleFile.ts, 9, 3))
+>C : Symbol(C, Decl(ambientClassDeclarationExtends_singleFile.ts, 1, 29))
+>D : Symbol(D, Decl(ambientClassDeclarationExtends_singleFile.ts, 5, 1), Decl(ambientClassDeclarationExtends_singleFile.ts, 6, 22))
+
+=== tests/cases/compiler/ambientClassDeclarationExtends_file1.ts ===
+
+declare class E {
+>E : Symbol(E, Decl(ambientClassDeclarationExtends_file1.ts, 0, 0))
+
+    public bar;
+>bar : Symbol(bar, Decl(ambientClassDeclarationExtends_file1.ts, 1, 17))
+}
+namespace F { var y; }
+>F : Symbol(F, Decl(ambientClassDeclarationExtends_file1.ts, 3, 1), Decl(ambientClassDeclarationExtends_file2.ts, 0, 0))
+>y : Symbol(y, Decl(ambientClassDeclarationExtends_file1.ts, 4, 17))
+
+=== tests/cases/compiler/ambientClassDeclarationExtends_file2.ts ===
+
+declare class F extends E { }
+>F : Symbol(F, Decl(ambientClassDeclarationExtends_file1.ts, 3, 1), Decl(ambientClassDeclarationExtends_file2.ts, 0, 0))
+>E : Symbol(E, Decl(ambientClassDeclarationExtends_file1.ts, 0, 0))
+
+var f: E = new F();
+>f : Symbol(f, Decl(ambientClassDeclarationExtends_file2.ts, 2, 3))
+>E : Symbol(E, Decl(ambientClassDeclarationExtends_file1.ts, 0, 0))
+>F : Symbol(F, Decl(ambientClassDeclarationExtends_file1.ts, 3, 1), Decl(ambientClassDeclarationExtends_file2.ts, 0, 0))
 
diff --git a/tests/baselines/reference/ambientClassDeclarationWithExtends.types b/tests/baselines/reference/ambientClassDeclarationWithExtends.types
index 528496e753d..c7f22eeb65f 100644
--- a/tests/baselines/reference/ambientClassDeclarationWithExtends.types
+++ b/tests/baselines/reference/ambientClassDeclarationWithExtends.types
@@ -1,4 +1,4 @@
-=== tests/cases/compiler/ambientClassDeclarationWithExtends.ts ===
+=== tests/cases/compiler/ambientClassDeclarationExtends_singleFile.ts ===
 declare class A { }
 >A : A
 
@@ -26,3 +26,27 @@ var d: C = new D();
 >new D() : D
 >D : typeof D
 
+=== tests/cases/compiler/ambientClassDeclarationExtends_file1.ts ===
+
+declare class E {
+>E : E
+
+    public bar;
+>bar : any
+}
+namespace F { var y; }
+>F : typeof F
+>y : any
+
+=== tests/cases/compiler/ambientClassDeclarationExtends_file2.ts ===
+
+declare class F extends E { }
+>F : F
+>E : E
+
+var f: E = new F();
+>f : E
+>E : E
+>new F() : F
+>F : typeof F
+
diff --git a/tests/cases/compiler/ambientClassDeclarationWithExtends.ts b/tests/cases/compiler/ambientClassDeclarationWithExtends.ts
index 554a436c5ef..ca26f1b2a44 100644
--- a/tests/cases/compiler/ambientClassDeclarationWithExtends.ts
+++ b/tests/cases/compiler/ambientClassDeclarationWithExtends.ts
@@ -1,3 +1,4 @@
+// @Filename: ambientClassDeclarationExtends_singleFile.ts
 declare class A { }
 declare class B extends A { }
 
@@ -8,3 +9,15 @@ namespace D { var x; }
 declare class D extends C { }
 
 var d: C = new D();
+
+// @Filename: ambientClassDeclarationExtends_file1.ts
+
+declare class E {
+    public bar;
+}
+namespace F { var y; }
+
+// @Filename: ambientClassDeclarationExtends_file2.ts
+
+declare class F extends E { }
+var f: E = new F();