Merge pull request #5290 from Microsoft/interfaceClassMergingFix

Do not report errors for classes and interfaces merging

src/compiler/checker.ts

@@ -12875,11 +12875,6 @@ namespace ts {
             }
             checkClassLikeDeclaration(node);
 
-            // Interfaces cannot be merged with non-ambient classes.
-            if (getSymbolOfNode(node).flags & SymbolFlags.Interface && !isInAmbientContext(node)) {
-                error(node, Diagnostics.Only_an_ambient_class_can_be_merged_with_an_interface);
-            }
-
             forEach(node.members, checkSourceElement);
         }
 
@@ -13165,16 +13160,6 @@ namespace ts {
                         checkIndexConstraints(type);
                     }
                 }
-
-                // Interfaces cannot merge with non-ambient classes.
-                if (symbol && symbol.declarations) {
-                    for (let declaration of symbol.declarations) {
-                        if (declaration.kind === SyntaxKind.ClassDeclaration && !isInAmbientContext(declaration)) {
-                            error(node, Diagnostics.Only_an_ambient_class_can_be_merged_with_an_interface);
-                            break;
-                        }
-                    }
-                }
             }
             forEach(getInterfaceBaseTypeNodes(node), heritageElement => {
                 if (!isSupportedExpressionWithTypeArguments(heritageElement)) {

src/compiler/diagnosticMessages.json

@@ -1620,10 +1620,6 @@
         "category": "Error",
         "code":2517
     },
-    "Only an ambient class can be merged with an interface.": {
-        "category": "Error",
-        "code": 2518
-    },
     "Duplicate identifier '{0}'. Compiler uses declaration '{1}' to support async functions.": {
         "category": "Error",
         "code": 2520

tests/baselines/reference/augmentedTypesClass2.errors.txt

@@ -1,24 +1,18 @@
-tests/cases/compiler/augmentedTypesClass2.ts(4,7): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/augmentedTypesClass2.ts(10,11): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/augmentedTypesClass2.ts(16,7): error TS2300: Duplicate identifier 'c33'.
 tests/cases/compiler/augmentedTypesClass2.ts(21,6): error TS2300: Duplicate identifier 'c33'.
 
 
-==== tests/cases/compiler/augmentedTypesClass2.ts (4 errors) ====
+==== tests/cases/compiler/augmentedTypesClass2.ts (2 errors) ====
     // Checking class with other things in type space not value space
     
     // class then interface
-    class c11 { // error
-          ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+    class c11 {
         foo() {
             return 1;
         }
     }
     
-    interface c11 { // error
-              ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+    interface c11 {
         bar(): void;
     }
     

tests/baselines/reference/augmentedTypesClass2.js

@@ -2,13 +2,13 @@
 // Checking class with other things in type space not value space
 
 // class then interface
-class c11 { // error
+class c11 {
     foo() {
         return 1;
     }
 }
 
-interface c11 { // error
+interface c11 {
     bar(): void;
 }
 

tests/baselines/reference/augmentedTypesInterface.errors.txt

@@ -1,10 +1,8 @@
-tests/cases/compiler/augmentedTypesInterface.ts(12,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/augmentedTypesInterface.ts(16,7): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/augmentedTypesInterface.ts(23,11): error TS2300: Duplicate identifier 'i3'.
 tests/cases/compiler/augmentedTypesInterface.ts(26,6): error TS2300: Duplicate identifier 'i3'.
 
 
-==== tests/cases/compiler/augmentedTypesInterface.ts (4 errors) ====
+==== tests/cases/compiler/augmentedTypesInterface.ts (2 errors) ====
     // interface then interface
     
     interface i {
@@ -16,15 +14,11 @@ tests/cases/compiler/augmentedTypesInterface.ts(26,6): error TS2300: Duplicate i
     }
     
     // interface then class
-    interface i2 { // error
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+    interface i2 {
         foo(): void;
     }
     
-    class i2 {  // error
-          ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+    class i2 {
         bar() {
             return 1;
         }

tests/baselines/reference/augmentedTypesInterface.js

@@ -10,11 +10,11 @@ interface i {
 }
 
 // interface then class
-interface i2 { // error
+interface i2 {
     foo(): void;
 }
 
-class i2 {  // error
+class i2 {
     bar() {
         return 1;
     }

tests/baselines/reference/classAbstractMergedDeclaration.errors.txt

@@ -1,7 +1,3 @@
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(7,16): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(8,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(10,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(11,16): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(13,16): error TS2300: Duplicate identifier 'CC1'.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(14,7): error TS2300: Duplicate identifier 'CC1'.
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(16,7): error TS2300: Duplicate identifier 'CC2'.
@@ -20,7 +16,7 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts(39,1): error TS2511: Cannot create an instance of the abstract class 'DCC1'.
 
 
-==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts (20 errors) ====
+==== tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractMergedDeclaration.ts (16 errors) ====
     abstract class CM {}
     module CM {}
     
@@ -28,18 +24,10 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     abstract class MC {}
     
     abstract class CI {}
-                   ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     interface CI {}
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     
     interface IC {}
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     abstract class IC {}
-                   ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     
     abstract class CC1 {}
                    ~~~

tests/baselines/reference/classAndInterfaceWithSameName.errors.txt

@@ -1,37 +1,25 @@
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(1,7): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(1,11): error TS2300: Duplicate identifier 'foo'.
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(2,11): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(2,15): error TS2300: Duplicate identifier 'foo'.
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(5,11): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(6,9): error TS2300: Duplicate identifier 'bar'.
-tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(9,15): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts(10,9): error TS2300: Duplicate identifier 'bar'.
 
 
-==== tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts (8 errors) ====
+==== tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts (4 errors) ====
     class C { foo: string; }
-          ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
               ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
-    interface C { foo: string; } // error
-              ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+    interface C { foo: string; }
                   ~~~
 !!! error TS2300: Duplicate identifier 'foo'.
     
     module M {
         class D {
-              ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
             bar: string;
             ~~~
 !!! error TS2300: Duplicate identifier 'bar'.
         }
     
-        interface D { // error
-                  ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+        interface D {
             bar: string;
             ~~~
 !!! error TS2300: Duplicate identifier 'bar'.

tests/baselines/reference/classAndInterfaceWithSameName.js

@@ -1,13 +1,13 @@
 //// [classAndInterfaceWithSameName.ts]
 class C { foo: string; }
-interface C { foo: string; } // error
+interface C { foo: string; }
 
 module M {
     class D {
         bar: string;
     }
 
-    interface D { // error
+    interface D {
         bar: string;
     }
 }

tests/baselines/reference/clinterfaces.errors.txt

@@ -1,52 +0,0 @@
-tests/cases/compiler/clinterfaces.ts(2,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(3,15): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(4,15): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(5,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(8,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(12,7): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(16,7): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/clinterfaces.ts(20,11): error TS2518: Only an ambient class can be merged with an interface.
-
-
-==== tests/cases/compiler/clinterfaces.ts (8 errors) ====
-    module M {
-        class C { }
-              ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        interface C { }
-                  ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        interface D { }
-                  ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        class D { }
-              ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    }
-    
-    interface Foo<T> {
-              ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        a: string;
-    }
-    
-    class Foo<T>{
-          ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        b: number;
-    }
-    
-    class Bar<T>{
-          ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        b: number;
-    }
-    
-    interface Bar<T> {
-              ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        a: string;
-    }
-    
-    export = Foo;
-    

tests/baselines/reference/clinterfaces.symbols

@@ -0,0 +1,52 @@
+=== tests/cases/compiler/clinterfaces.ts ===
+module M {
+>M : Symbol(M, Decl(clinterfaces.ts, 0, 0))
+
+    class C { }
+>C : Symbol(C, Decl(clinterfaces.ts, 0, 10), Decl(clinterfaces.ts, 1, 15))
+
+    interface C { }
+>C : Symbol(C, Decl(clinterfaces.ts, 0, 10), Decl(clinterfaces.ts, 1, 15))
+
+    interface D { }
+>D : Symbol(D, Decl(clinterfaces.ts, 2, 19), Decl(clinterfaces.ts, 3, 19))
+
+    class D { }
+>D : Symbol(D, Decl(clinterfaces.ts, 2, 19), Decl(clinterfaces.ts, 3, 19))
+}
+
+interface Foo<T> {
+>Foo : Symbol(Foo, Decl(clinterfaces.ts, 5, 1), Decl(clinterfaces.ts, 9, 1))
+>T : Symbol(T, Decl(clinterfaces.ts, 7, 14), Decl(clinterfaces.ts, 11, 10))
+
+    a: string;
+>a : Symbol(a, Decl(clinterfaces.ts, 7, 18))
+}
+
+class Foo<T>{
+>Foo : Symbol(Foo, Decl(clinterfaces.ts, 5, 1), Decl(clinterfaces.ts, 9, 1))
+>T : Symbol(T, Decl(clinterfaces.ts, 7, 14), Decl(clinterfaces.ts, 11, 10))
+
+    b: number;
+>b : Symbol(b, Decl(clinterfaces.ts, 11, 13))
+}
+
+class Bar<T>{
+>Bar : Symbol(Bar, Decl(clinterfaces.ts, 13, 1), Decl(clinterfaces.ts, 17, 1))
+>T : Symbol(T, Decl(clinterfaces.ts, 15, 10), Decl(clinterfaces.ts, 19, 14))
+
+    b: number;
+>b : Symbol(b, Decl(clinterfaces.ts, 15, 13))
+}
+
+interface Bar<T> {
+>Bar : Symbol(Bar, Decl(clinterfaces.ts, 13, 1), Decl(clinterfaces.ts, 17, 1))
+>T : Symbol(T, Decl(clinterfaces.ts, 15, 10), Decl(clinterfaces.ts, 19, 14))
+
+    a: string;
+>a : Symbol(a, Decl(clinterfaces.ts, 19, 18))
+}
+
+export = Foo;
+>Foo : Symbol(Foo, Decl(clinterfaces.ts, 5, 1), Decl(clinterfaces.ts, 9, 1))
+

tests/baselines/reference/clinterfaces.types

@@ -0,0 +1,52 @@
+=== tests/cases/compiler/clinterfaces.ts ===
+module M {
+>M : typeof M
+
+    class C { }
+>C : C
+
+    interface C { }
+>C : C
+
+    interface D { }
+>D : D
+
+    class D { }
+>D : D
+}
+
+interface Foo<T> {
+>Foo : Foo<T>
+>T : T
+
+    a: string;
+>a : string
+}
+
+class Foo<T>{
+>Foo : Foo<T>
+>T : T
+
+    b: number;
+>b : number
+}
+
+class Bar<T>{
+>Bar : Bar<T>
+>T : T
+
+    b: number;
+>b : number
+}
+
+interface Bar<T> {
+>Bar : Bar<T>
+>T : T
+
+    a: string;
+>a : string
+}
+
+export = Foo;
+>Foo : Foo<T>
+

tests/baselines/reference/declInput.errors.txt

@@ -1,19 +0,0 @@
-tests/cases/compiler/declInput.ts(1,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/declInput.ts(5,7): error TS2518: Only an ambient class can be merged with an interface.
-
-
-==== tests/cases/compiler/declInput.ts (2 errors) ====
-    interface bar {
-              ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    
-    }
-    
-    class bar {
-          ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-      public f() { return ''; }
-      public g() { return {a: <bar>null, b: undefined, c: void 4 }; }
-      public h(x = 4, y = null, z = '') { x++; }
-    }
-    

tests/baselines/reference/declInput.symbols

@@ -0,0 +1,28 @@
+=== tests/cases/compiler/declInput.ts ===
+interface bar {
+>bar : Symbol(bar, Decl(declInput.ts, 0, 0), Decl(declInput.ts, 2, 1))
+
+}
+
+class bar {
+>bar : Symbol(bar, Decl(declInput.ts, 0, 0), Decl(declInput.ts, 2, 1))
+
+  public f() { return ''; }
+>f : Symbol(f, Decl(declInput.ts, 4, 11))
+
+  public g() { return {a: <bar>null, b: undefined, c: void 4 }; }
+>g : Symbol(g, Decl(declInput.ts, 5, 27))
+>a : Symbol(a, Decl(declInput.ts, 6, 23))
+>bar : Symbol(bar, Decl(declInput.ts, 0, 0), Decl(declInput.ts, 2, 1))
+>b : Symbol(b, Decl(declInput.ts, 6, 36))
+>undefined : Symbol(undefined)
+>c : Symbol(c, Decl(declInput.ts, 6, 50))
+
+  public h(x = 4, y = null, z = '') { x++; }
+>h : Symbol(h, Decl(declInput.ts, 6, 65))
+>x : Symbol(x, Decl(declInput.ts, 7, 11))
+>y : Symbol(y, Decl(declInput.ts, 7, 17))
+>z : Symbol(z, Decl(declInput.ts, 7, 27))
+>x : Symbol(x, Decl(declInput.ts, 7, 11))
+}
+

tests/baselines/reference/declInput.types

@@ -0,0 +1,38 @@
+=== tests/cases/compiler/declInput.ts ===
+interface bar {
+>bar : bar
+
+}
+
+class bar {
+>bar : bar
+
+  public f() { return ''; }
+>f : () => string
+>'' : string
+
+  public g() { return {a: <bar>null, b: undefined, c: void 4 }; }
+>g : () => { a: bar; b: any; c: any; }
+>{a: <bar>null, b: undefined, c: void 4 } : { a: bar; b: undefined; c: undefined; }
+>a : bar
+><bar>null : bar
+>bar : bar
+>null : null
+>b : undefined
+>undefined : undefined
+>c : undefined
+>void 4 : undefined
+>4 : number
+
+  public h(x = 4, y = null, z = '') { x++; }
+>h : (x?: number, y?: any, z?: string) => void
+>x : number
+>4 : number
+>y : any
+>null : null
+>z : string
+>'' : string
+>x++ : number
+>x : number
+}
+

tests/baselines/reference/defaultExportsCannotMerge03.errors.txt

@@ -1,10 +1,9 @@
 tests/cases/conformance/es6/modules/m1.ts(2,22): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
-tests/cases/conformance/es6/modules/m1.ts(5,11): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/conformance/es6/modules/m1.ts(5,11): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
 tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1'.
 
 
-==== tests/cases/conformance/es6/modules/m1.ts (3 errors) ====
+==== tests/cases/conformance/es6/modules/m1.ts (2 errors) ====
     
     export default class Decl {
                          ~~~~
@@ -13,8 +12,6 @@ tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find modul
     
     interface Decl {
               ~~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-              ~~~~
 !!! error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
         p1: number;
         p2: number;

tests/baselines/reference/duplicateIdentifiersAcrossContainerBoundaries.errors.txt

@@ -1,21 +1,15 @@
-tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(2,22): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(5,18): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(9,21): error TS2300: Duplicate identifier 'f'.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(12,18): error TS2300: Duplicate identifier 'f'.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(37,12): error TS2300: Duplicate identifier 'x'.
 tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts(41,16): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts (6 errors) ====
+==== tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts (4 errors) ====
     module M {
         export interface I { }
-                         ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     }
     module M {
-        export class I { } // error
-                     ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+        export class I { }
     }
     
     module M {

tests/baselines/reference/duplicateIdentifiersAcrossContainerBoundaries.js

@@ -3,7 +3,7 @@ module M {
     export interface I { }
 }
 module M {
-    export class I { } // error
+    export class I { }
 }
 
 module M {
@@ -60,7 +60,7 @@ var M;
         }
         return I;
     })();
-    M.I = I; // error
+    M.I = I;
 })(M || (M = {}));
 var M;
 (function (M) {

tests/baselines/reference/duplicateIdentifiersAcrossFileBoundaries.errors.txt

@@ -1,24 +1,16 @@
-tests/cases/compiler/file1.ts(2,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/file1.ts(3,7): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/file1.ts(4,7): error TS2300: Duplicate identifier 'C2'.
 tests/cases/compiler/file1.ts(5,10): error TS2300: Duplicate identifier 'f'.
 tests/cases/compiler/file1.ts(9,12): error TS2300: Duplicate identifier 'x'.
-tests/cases/compiler/file2.ts(1,7): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/file2.ts(2,11): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/file2.ts(3,10): error TS2300: Duplicate identifier 'C2'.
 tests/cases/compiler/file2.ts(4,7): error TS2300: Duplicate identifier 'f'.
 tests/cases/compiler/file2.ts(7,8): error TS2433: A namespace declaration cannot be in a different file from a class or function with which it is merged
 tests/cases/compiler/file2.ts(8,16): error TS2300: Duplicate identifier 'x'.
 
 
-==== tests/cases/compiler/file1.ts (5 errors) ====
+==== tests/cases/compiler/file1.ts (3 errors) ====
     
     interface I { }
-              ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     class C1 { }
-          ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     class C2 { }
           ~~
 !!! error TS2300: Duplicate identifier 'C2'.
@@ -39,13 +31,9 @@ tests/cases/compiler/file2.ts(8,16): error TS2300: Duplicate identifier 'x'.
         }
     }
     
-==== tests/cases/compiler/file2.ts (6 errors) ====
+==== tests/cases/compiler/file2.ts (4 errors) ====
     class I { } // error -- cannot merge interface with non-ambient class
-          ~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     interface C1 { } // error -- cannot merge interface with non-ambient class
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     function C2() { } // error -- cannot merge function with non-ambient class
              ~~
 !!! error TS2300: Duplicate identifier 'C2'.

tests/baselines/reference/interfaceClassMerging.js

@@ -0,0 +1,76 @@
+//// [interfaceClassMerging.ts]
+interface Foo {
+    method(a: number): string;
+    optionalMethod?(a: number): string;
+    property: string;
+    optionalProperty?: string;
+}
+
+class Foo {
+    additionalProperty: string;
+
+    additionalMethod(a: number): string {
+        return this.method(0);
+    }
+}
+
+class Bar extends Foo {
+    method(a: number) {
+        return this.optionalProperty;
+    }
+}
+
+
+var bar = new Bar();
+bar.method(0);
+bar.optionalMethod(1);
+bar.property;
+bar.optionalProperty;
+bar.additionalProperty;
+bar.additionalMethod(2);
+
+var obj: {
+    method(a: number): string;
+    property: string;
+    additionalProperty: string;
+    additionalMethod(a: number): string;
+};
+
+bar = obj;
+obj = bar;
+
+
+//// [interfaceClassMerging.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Foo = (function () {
+    function Foo() {
+    }
+    Foo.prototype.additionalMethod = function (a) {
+        return this.method(0);
+    };
+    return Foo;
+})();
+var Bar = (function (_super) {
+    __extends(Bar, _super);
+    function Bar() {
+        _super.apply(this, arguments);
+    }
+    Bar.prototype.method = function (a) {
+        return this.optionalProperty;
+    };
+    return Bar;
+})(Foo);
+var bar = new Bar();
+bar.method(0);
+bar.optionalMethod(1);
+bar.property;
+bar.optionalProperty;
+bar.additionalProperty;
+bar.additionalMethod(2);
+var obj;
+bar = obj;
+obj = bar;

tests/baselines/reference/interfaceClassMerging.symbols

@@ -0,0 +1,113 @@
+=== tests/cases/compiler/interfaceClassMerging.ts ===
+interface Foo {
+>Foo : Symbol(Foo, Decl(interfaceClassMerging.ts, 0, 0), Decl(interfaceClassMerging.ts, 5, 1))
+
+    method(a: number): string;
+>method : Symbol(method, Decl(interfaceClassMerging.ts, 0, 15))
+>a : Symbol(a, Decl(interfaceClassMerging.ts, 1, 11))
+
+    optionalMethod?(a: number): string;
+>optionalMethod : Symbol(optionalMethod, Decl(interfaceClassMerging.ts, 1, 30))
+>a : Symbol(a, Decl(interfaceClassMerging.ts, 2, 20))
+
+    property: string;
+>property : Symbol(property, Decl(interfaceClassMerging.ts, 2, 39))
+
+    optionalProperty?: string;
+>optionalProperty : Symbol(optionalProperty, Decl(interfaceClassMerging.ts, 3, 21))
+}
+
+class Foo {
+>Foo : Symbol(Foo, Decl(interfaceClassMerging.ts, 0, 0), Decl(interfaceClassMerging.ts, 5, 1))
+
+    additionalProperty: string;
+>additionalProperty : Symbol(additionalProperty, Decl(interfaceClassMerging.ts, 7, 11))
+
+    additionalMethod(a: number): string {
+>additionalMethod : Symbol(additionalMethod, Decl(interfaceClassMerging.ts, 8, 31))
+>a : Symbol(a, Decl(interfaceClassMerging.ts, 10, 21))
+
+        return this.method(0);
+>this.method : Symbol(method, Decl(interfaceClassMerging.ts, 0, 15))
+>this : Symbol(Foo, Decl(interfaceClassMerging.ts, 0, 0), Decl(interfaceClassMerging.ts, 5, 1))
+>method : Symbol(method, Decl(interfaceClassMerging.ts, 0, 15))
+    }
+}
+
+class Bar extends Foo {
+>Bar : Symbol(Bar, Decl(interfaceClassMerging.ts, 13, 1))
+>Foo : Symbol(Foo, Decl(interfaceClassMerging.ts, 0, 0), Decl(interfaceClassMerging.ts, 5, 1))
+
+    method(a: number) {
+>method : Symbol(method, Decl(interfaceClassMerging.ts, 15, 23))
+>a : Symbol(a, Decl(interfaceClassMerging.ts, 16, 11))
+
+        return this.optionalProperty;
+>this.optionalProperty : Symbol(Foo.optionalProperty, Decl(interfaceClassMerging.ts, 3, 21))
+>this : Symbol(Bar, Decl(interfaceClassMerging.ts, 13, 1))
+>optionalProperty : Symbol(Foo.optionalProperty, Decl(interfaceClassMerging.ts, 3, 21))
+    }
+}
+
+
+var bar = new Bar();
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>Bar : Symbol(Bar, Decl(interfaceClassMerging.ts, 13, 1))
+
+bar.method(0);
+>bar.method : Symbol(Bar.method, Decl(interfaceClassMerging.ts, 15, 23))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>method : Symbol(Bar.method, Decl(interfaceClassMerging.ts, 15, 23))
+
+bar.optionalMethod(1);
+>bar.optionalMethod : Symbol(Foo.optionalMethod, Decl(interfaceClassMerging.ts, 1, 30))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>optionalMethod : Symbol(Foo.optionalMethod, Decl(interfaceClassMerging.ts, 1, 30))
+
+bar.property;
+>bar.property : Symbol(Foo.property, Decl(interfaceClassMerging.ts, 2, 39))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>property : Symbol(Foo.property, Decl(interfaceClassMerging.ts, 2, 39))
+
+bar.optionalProperty;
+>bar.optionalProperty : Symbol(Foo.optionalProperty, Decl(interfaceClassMerging.ts, 3, 21))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>optionalProperty : Symbol(Foo.optionalProperty, Decl(interfaceClassMerging.ts, 3, 21))
+
+bar.additionalProperty;
+>bar.additionalProperty : Symbol(Foo.additionalProperty, Decl(interfaceClassMerging.ts, 7, 11))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>additionalProperty : Symbol(Foo.additionalProperty, Decl(interfaceClassMerging.ts, 7, 11))
+
+bar.additionalMethod(2);
+>bar.additionalMethod : Symbol(Foo.additionalMethod, Decl(interfaceClassMerging.ts, 8, 31))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>additionalMethod : Symbol(Foo.additionalMethod, Decl(interfaceClassMerging.ts, 8, 31))
+
+var obj: {
+>obj : Symbol(obj, Decl(interfaceClassMerging.ts, 30, 3))
+
+    method(a: number): string;
+>method : Symbol(method, Decl(interfaceClassMerging.ts, 30, 10))
+>a : Symbol(a, Decl(interfaceClassMerging.ts, 31, 11))
+
+    property: string;
+>property : Symbol(property, Decl(interfaceClassMerging.ts, 31, 30))
+
+    additionalProperty: string;
+>additionalProperty : Symbol(additionalProperty, Decl(interfaceClassMerging.ts, 32, 21))
+
+    additionalMethod(a: number): string;
+>additionalMethod : Symbol(additionalMethod, Decl(interfaceClassMerging.ts, 33, 31))
+>a : Symbol(a, Decl(interfaceClassMerging.ts, 34, 21))
+
+};
+
+bar = obj;
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+>obj : Symbol(obj, Decl(interfaceClassMerging.ts, 30, 3))
+
+obj = bar;
+>obj : Symbol(obj, Decl(interfaceClassMerging.ts, 30, 3))
+>bar : Symbol(bar, Decl(interfaceClassMerging.ts, 22, 3))
+

tests/baselines/reference/interfaceClassMerging.types

@@ -0,0 +1,124 @@
+=== tests/cases/compiler/interfaceClassMerging.ts ===
+interface Foo {
+>Foo : Foo
+
+    method(a: number): string;
+>method : (a: number) => string
+>a : number
+
+    optionalMethod?(a: number): string;
+>optionalMethod : (a: number) => string
+>a : number
+
+    property: string;
+>property : string
+
+    optionalProperty?: string;
+>optionalProperty : string
+}
+
+class Foo {
+>Foo : Foo
+
+    additionalProperty: string;
+>additionalProperty : string
+
+    additionalMethod(a: number): string {
+>additionalMethod : (a: number) => string
+>a : number
+
+        return this.method(0);
+>this.method(0) : string
+>this.method : (a: number) => string
+>this : this
+>method : (a: number) => string
+>0 : number
+    }
+}
+
+class Bar extends Foo {
+>Bar : Bar
+>Foo : Foo
+
+    method(a: number) {
+>method : (a: number) => string
+>a : number
+
+        return this.optionalProperty;
+>this.optionalProperty : string
+>this : this
+>optionalProperty : string
+    }
+}
+
+
+var bar = new Bar();
+>bar : Bar
+>new Bar() : Bar
+>Bar : typeof Bar
+
+bar.method(0);
+>bar.method(0) : string
+>bar.method : (a: number) => string
+>bar : Bar
+>method : (a: number) => string
+>0 : number
+
+bar.optionalMethod(1);
+>bar.optionalMethod(1) : string
+>bar.optionalMethod : (a: number) => string
+>bar : Bar
+>optionalMethod : (a: number) => string
+>1 : number
+
+bar.property;
+>bar.property : string
+>bar : Bar
+>property : string
+
+bar.optionalProperty;
+>bar.optionalProperty : string
+>bar : Bar
+>optionalProperty : string
+
+bar.additionalProperty;
+>bar.additionalProperty : string
+>bar : Bar
+>additionalProperty : string
+
+bar.additionalMethod(2);
+>bar.additionalMethod(2) : string
+>bar.additionalMethod : (a: number) => string
+>bar : Bar
+>additionalMethod : (a: number) => string
+>2 : number
+
+var obj: {
+>obj : { method(a: number): string; property: string; additionalProperty: string; additionalMethod(a: number): string; }
+
+    method(a: number): string;
+>method : (a: number) => string
+>a : number
+
+    property: string;
+>property : string
+
+    additionalProperty: string;
+>additionalProperty : string
+
+    additionalMethod(a: number): string;
+>additionalMethod : (a: number) => string
+>a : number
+
+};
+
+bar = obj;
+>bar = obj : { method(a: number): string; property: string; additionalProperty: string; additionalMethod(a: number): string; }
+>bar : Bar
+>obj : { method(a: number): string; property: string; additionalProperty: string; additionalMethod(a: number): string; }
+
+obj = bar;
+>obj = bar : Bar
+>obj : { method(a: number): string; property: string; additionalProperty: string; additionalMethod(a: number): string; }
+>bar : Bar
+

tests/baselines/reference/interfaceClassMerging2.js

@@ -0,0 +1,66 @@
+//// [interfaceClassMerging2.ts]
+interface Foo {
+    interfaceFooMethod(): this;
+    interfaceFooProperty: this;
+}
+
+class Foo {
+    classFooProperty: this;
+
+    classFooMethod(): this {
+        return this;
+    }
+}
+
+
+interface Bar {
+    interfaceBarMethod(): this;
+    interfaceBarProperty: this;
+}
+
+class Bar extends Foo {
+    classBarProperty: this;
+
+    classBarMethod(): this {
+        return this;
+    }
+}
+
+
+var bar = new Bar();
+bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod();
+
+
+var foo = new Foo();
+
+foo = bar;
+
+
+//// [interfaceClassMerging2.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var Foo = (function () {
+    function Foo() {
+    }
+    Foo.prototype.classFooMethod = function () {
+        return this;
+    };
+    return Foo;
+})();
+var Bar = (function (_super) {
+    __extends(Bar, _super);
+    function Bar() {
+        _super.apply(this, arguments);
+    }
+    Bar.prototype.classBarMethod = function () {
+        return this;
+    };
+    return Bar;
+})(Foo);
+var bar = new Bar();
+bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod();
+var foo = new Foo();
+foo = bar;

tests/baselines/reference/interfaceClassMerging2.symbols

@@ -0,0 +1,76 @@
+=== tests/cases/compiler/interfaceClassMerging2.ts ===
+interface Foo {
+>Foo : Symbol(Foo, Decl(interfaceClassMerging2.ts, 0, 0), Decl(interfaceClassMerging2.ts, 3, 1))
+
+    interfaceFooMethod(): this;
+>interfaceFooMethod : Symbol(interfaceFooMethod, Decl(interfaceClassMerging2.ts, 0, 15))
+
+    interfaceFooProperty: this;
+>interfaceFooProperty : Symbol(interfaceFooProperty, Decl(interfaceClassMerging2.ts, 1, 31))
+}
+
+class Foo {
+>Foo : Symbol(Foo, Decl(interfaceClassMerging2.ts, 0, 0), Decl(interfaceClassMerging2.ts, 3, 1))
+
+    classFooProperty: this;
+>classFooProperty : Symbol(classFooProperty, Decl(interfaceClassMerging2.ts, 5, 11))
+
+    classFooMethod(): this {
+>classFooMethod : Symbol(classFooMethod, Decl(interfaceClassMerging2.ts, 6, 27))
+
+        return this;
+>this : Symbol(Foo, Decl(interfaceClassMerging2.ts, 0, 0), Decl(interfaceClassMerging2.ts, 3, 1))
+    }
+}
+
+
+interface Bar {
+>Bar : Symbol(Bar, Decl(interfaceClassMerging2.ts, 11, 1), Decl(interfaceClassMerging2.ts, 17, 1))
+
+    interfaceBarMethod(): this;
+>interfaceBarMethod : Symbol(interfaceBarMethod, Decl(interfaceClassMerging2.ts, 14, 15))
+
+    interfaceBarProperty: this;
+>interfaceBarProperty : Symbol(interfaceBarProperty, Decl(interfaceClassMerging2.ts, 15, 31))
+}
+
+class Bar extends Foo {
+>Bar : Symbol(Bar, Decl(interfaceClassMerging2.ts, 11, 1), Decl(interfaceClassMerging2.ts, 17, 1))
+>Foo : Symbol(Foo, Decl(interfaceClassMerging2.ts, 0, 0), Decl(interfaceClassMerging2.ts, 3, 1))
+
+    classBarProperty: this;
+>classBarProperty : Symbol(classBarProperty, Decl(interfaceClassMerging2.ts, 19, 23))
+
+    classBarMethod(): this {
+>classBarMethod : Symbol(classBarMethod, Decl(interfaceClassMerging2.ts, 20, 27))
+
+        return this;
+>this : Symbol(Bar, Decl(interfaceClassMerging2.ts, 11, 1), Decl(interfaceClassMerging2.ts, 17, 1))
+    }
+}
+
+
+var bar = new Bar();
+>bar : Symbol(bar, Decl(interfaceClassMerging2.ts, 28, 3))
+>Bar : Symbol(Bar, Decl(interfaceClassMerging2.ts, 11, 1), Decl(interfaceClassMerging2.ts, 17, 1))
+
+bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod();
+>bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod : Symbol(Foo.classFooMethod, Decl(interfaceClassMerging2.ts, 6, 27))
+>bar.interfaceBarMethod().interfaceFooMethod().classBarMethod : Symbol(Bar.classBarMethod, Decl(interfaceClassMerging2.ts, 20, 27))
+>bar.interfaceBarMethod().interfaceFooMethod : Symbol(Foo.interfaceFooMethod, Decl(interfaceClassMerging2.ts, 0, 15))
+>bar.interfaceBarMethod : Symbol(Bar.interfaceBarMethod, Decl(interfaceClassMerging2.ts, 14, 15))
+>bar : Symbol(bar, Decl(interfaceClassMerging2.ts, 28, 3))
+>interfaceBarMethod : Symbol(Bar.interfaceBarMethod, Decl(interfaceClassMerging2.ts, 14, 15))
+>interfaceFooMethod : Symbol(Foo.interfaceFooMethod, Decl(interfaceClassMerging2.ts, 0, 15))
+>classBarMethod : Symbol(Bar.classBarMethod, Decl(interfaceClassMerging2.ts, 20, 27))
+>classFooMethod : Symbol(Foo.classFooMethod, Decl(interfaceClassMerging2.ts, 6, 27))
+
+
+var foo = new Foo();
+>foo : Symbol(foo, Decl(interfaceClassMerging2.ts, 32, 3))
+>Foo : Symbol(Foo, Decl(interfaceClassMerging2.ts, 0, 0), Decl(interfaceClassMerging2.ts, 3, 1))
+
+foo = bar;
+>foo : Symbol(foo, Decl(interfaceClassMerging2.ts, 32, 3))
+>bar : Symbol(bar, Decl(interfaceClassMerging2.ts, 28, 3))
+

tests/baselines/reference/interfaceClassMerging2.types

@@ -0,0 +1,83 @@
+=== tests/cases/compiler/interfaceClassMerging2.ts ===
+interface Foo {
+>Foo : Foo
+
+    interfaceFooMethod(): this;
+>interfaceFooMethod : () => this
+
+    interfaceFooProperty: this;
+>interfaceFooProperty : this
+}
+
+class Foo {
+>Foo : Foo
+
+    classFooProperty: this;
+>classFooProperty : this
+
+    classFooMethod(): this {
+>classFooMethod : () => this
+
+        return this;
+>this : this
+    }
+}
+
+
+interface Bar {
+>Bar : Bar
+
+    interfaceBarMethod(): this;
+>interfaceBarMethod : () => this
+
+    interfaceBarProperty: this;
+>interfaceBarProperty : this
+}
+
+class Bar extends Foo {
+>Bar : Bar
+>Foo : Foo
+
+    classBarProperty: this;
+>classBarProperty : this
+
+    classBarMethod(): this {
+>classBarMethod : () => this
+
+        return this;
+>this : this
+    }
+}
+
+
+var bar = new Bar();
+>bar : Bar
+>new Bar() : Bar
+>Bar : typeof Bar
+
+bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod();
+>bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod() : Bar
+>bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod : () => Bar
+>bar.interfaceBarMethod().interfaceFooMethod().classBarMethod() : Bar
+>bar.interfaceBarMethod().interfaceFooMethod().classBarMethod : () => Bar
+>bar.interfaceBarMethod().interfaceFooMethod() : Bar
+>bar.interfaceBarMethod().interfaceFooMethod : () => Bar
+>bar.interfaceBarMethod() : Bar
+>bar.interfaceBarMethod : () => Bar
+>bar : Bar
+>interfaceBarMethod : () => Bar
+>interfaceFooMethod : () => Bar
+>classBarMethod : () => Bar
+>classFooMethod : () => Bar
+
+
+var foo = new Foo();
+>foo : Foo
+>new Foo() : Foo
+>Foo : typeof Foo
+
+foo = bar;
+>foo = bar : Bar
+>foo : Foo
+>bar : Bar
+

tests/baselines/reference/interfaceDeclaration2.errors.txt

@@ -1,22 +0,0 @@
-tests/cases/compiler/interfaceDeclaration2.ts(4,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/interfaceDeclaration2.ts(5,7): error TS2518: Only an ambient class can be merged with an interface.
-
-
-==== tests/cases/compiler/interfaceDeclaration2.ts (2 errors) ====
-    interface I1 { }
-    module I1 { }
-    
-    interface I2 { }
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    class I2 { }
-          ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    
-    interface I3 { }
-    function I3() { }
-    
-    interface I4 { }
-    var I4:number;
-    
-    

tests/baselines/reference/interfaceDeclaration2.symbols

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/interfaceDeclaration2.ts ===
+interface I1 { }
+>I1 : Symbol(I1, Decl(interfaceDeclaration2.ts, 0, 0), Decl(interfaceDeclaration2.ts, 0, 16))
+
+module I1 { }
+>I1 : Symbol(I1, Decl(interfaceDeclaration2.ts, 0, 0), Decl(interfaceDeclaration2.ts, 0, 16))
+
+interface I2 { }
+>I2 : Symbol(I2, Decl(interfaceDeclaration2.ts, 1, 13), Decl(interfaceDeclaration2.ts, 3, 16))
+
+class I2 { }
+>I2 : Symbol(I2, Decl(interfaceDeclaration2.ts, 1, 13), Decl(interfaceDeclaration2.ts, 3, 16))
+
+interface I3 { }
+>I3 : Symbol(I3, Decl(interfaceDeclaration2.ts, 4, 12), Decl(interfaceDeclaration2.ts, 6, 16))
+
+function I3() { }
+>I3 : Symbol(I3, Decl(interfaceDeclaration2.ts, 4, 12), Decl(interfaceDeclaration2.ts, 6, 16))
+
+interface I4 { }
+>I4 : Symbol(I4, Decl(interfaceDeclaration2.ts, 7, 17), Decl(interfaceDeclaration2.ts, 10, 3))
+
+var I4:number;
+>I4 : Symbol(I4, Decl(interfaceDeclaration2.ts, 7, 17), Decl(interfaceDeclaration2.ts, 10, 3))
+
+

tests/baselines/reference/interfaceDeclaration2.types

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/interfaceDeclaration2.ts ===
+interface I1 { }
+>I1 : I1
+
+module I1 { }
+>I1 : any
+
+interface I2 { }
+>I2 : I2
+
+class I2 { }
+>I2 : I2
+
+interface I3 { }
+>I3 : I3
+
+function I3() { }
+>I3 : () => void
+
+interface I4 { }
+>I4 : I4
+
+var I4:number;
+>I4 : number
+
+

tests/baselines/reference/mergedClassInterface.errors.txt

@@ -1,67 +0,0 @@
-tests/cases/conformance/classes/classDeclarations/file1.ts(11,7): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/conformance/classes/classDeclarations/file1.ts(13,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/conformance/classes/classDeclarations/file1.ts(15,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/conformance/classes/classDeclarations/file1.ts(17,7): error TS2518: Only an ambient class can be merged with an interface.
-
-
-==== tests/cases/conformance/classes/classDeclarations/file1.ts (4 errors) ====
-    
-    
-    declare class C1 { }
-    
-    interface C1 { }
-    
-    interface C2 { }
-    
-    declare class C2 { }
-    
-    class C3 { } // error -- cannot merge non-ambient class and interface
-          ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    
-    interface C3 { } // error -- cannot merge non-ambient class and interface
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    
-    interface C4 { } // error -- cannot merge non-ambient class and interface
-              ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    
-    class C4 { } // error -- cannot merge non-ambient class and interface
-          ~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-    
-    interface C5 {
-        x1: number;
-    }
-    
-    declare class C5 {
-        x2: number;
-    }
-    
-    interface C5 {
-        x3: number;
-    }
-    
-    interface C5 {
-        x4: number;
-    }
-    
-    // checks if properties actually were merged
-    var c5 : C5;
-    c5.x1;
-    c5.x2;
-    c5.x3;
-    c5.x4;
-    
-==== tests/cases/conformance/classes/classDeclarations/file2.ts (0 errors) ====
-    
-    declare class C6 { }
-    
-    interface C7 { }
-    
-==== tests/cases/conformance/classes/classDeclarations/file3.ts (0 errors) ====
-    
-    interface C6 { }
-    
-    declare class C7 { }

tests/baselines/reference/mergedClassInterface.js

@@ -11,13 +11,13 @@ interface C2 { }
 
 declare class C2 { }
 
-class C3 { } // error -- cannot merge non-ambient class and interface
+class C3 { }
 
-interface C3 { } // error -- cannot merge non-ambient class and interface
+interface C3 { }
 
-interface C4 { } // error -- cannot merge non-ambient class and interface
+interface C4 { }
 
-class C4 { } // error -- cannot merge non-ambient class and interface
+class C4 { }
 
 interface C5 {
     x1: number;
@@ -59,12 +59,12 @@ var C3 = (function () {
     function C3() {
     }
     return C3;
-})(); // error -- cannot merge non-ambient class and interface
+})();
 var C4 = (function () {
     function C4() {
     }
     return C4;
-})(); // error -- cannot merge non-ambient class and interface
+})();
 // checks if properties actually were merged
 var c5;
 c5.x1;

tests/baselines/reference/mergedClassInterface.symbols

@@ -0,0 +1,96 @@
+=== tests/cases/conformance/classes/classDeclarations/file1.ts ===
+
+
+declare class C1 { }
+>C1 : Symbol(C1, Decl(file1.ts, 0, 0), Decl(file1.ts, 2, 20))
+
+interface C1 { }
+>C1 : Symbol(C1, Decl(file1.ts, 0, 0), Decl(file1.ts, 2, 20))
+
+interface C2 { }
+>C2 : Symbol(C2, Decl(file1.ts, 4, 16), Decl(file1.ts, 6, 16))
+
+declare class C2 { }
+>C2 : Symbol(C2, Decl(file1.ts, 4, 16), Decl(file1.ts, 6, 16))
+
+class C3 { }
+>C3 : Symbol(C3, Decl(file1.ts, 8, 20), Decl(file1.ts, 10, 12))
+
+interface C3 { }
+>C3 : Symbol(C3, Decl(file1.ts, 8, 20), Decl(file1.ts, 10, 12))
+
+interface C4 { }
+>C4 : Symbol(C4, Decl(file1.ts, 12, 16), Decl(file1.ts, 14, 16))
+
+class C4 { }
+>C4 : Symbol(C4, Decl(file1.ts, 12, 16), Decl(file1.ts, 14, 16))
+
+interface C5 {
+>C5 : Symbol(C5, Decl(file1.ts, 16, 12), Decl(file1.ts, 20, 1), Decl(file1.ts, 24, 1), Decl(file1.ts, 28, 1))
+
+    x1: number;
+>x1 : Symbol(x1, Decl(file1.ts, 18, 14))
+}
+
+declare class C5 {
+>C5 : Symbol(C5, Decl(file1.ts, 16, 12), Decl(file1.ts, 20, 1), Decl(file1.ts, 24, 1), Decl(file1.ts, 28, 1))
+
+    x2: number;
+>x2 : Symbol(x2, Decl(file1.ts, 22, 18))
+}
+
+interface C5 {
+>C5 : Symbol(C5, Decl(file1.ts, 16, 12), Decl(file1.ts, 20, 1), Decl(file1.ts, 24, 1), Decl(file1.ts, 28, 1))
+
+    x3: number;
+>x3 : Symbol(x3, Decl(file1.ts, 26, 14))
+}
+
+interface C5 {
+>C5 : Symbol(C5, Decl(file1.ts, 16, 12), Decl(file1.ts, 20, 1), Decl(file1.ts, 24, 1), Decl(file1.ts, 28, 1))
+
+    x4: number;
+>x4 : Symbol(x4, Decl(file1.ts, 30, 14))
+}
+
+// checks if properties actually were merged
+var c5 : C5;
+>c5 : Symbol(c5, Decl(file1.ts, 35, 3))
+>C5 : Symbol(C5, Decl(file1.ts, 16, 12), Decl(file1.ts, 20, 1), Decl(file1.ts, 24, 1), Decl(file1.ts, 28, 1))
+
+c5.x1;
+>c5.x1 : Symbol(C5.x1, Decl(file1.ts, 18, 14))
+>c5 : Symbol(c5, Decl(file1.ts, 35, 3))
+>x1 : Symbol(C5.x1, Decl(file1.ts, 18, 14))
+
+c5.x2;
+>c5.x2 : Symbol(C5.x2, Decl(file1.ts, 22, 18))
+>c5 : Symbol(c5, Decl(file1.ts, 35, 3))
+>x2 : Symbol(C5.x2, Decl(file1.ts, 22, 18))
+
+c5.x3;
+>c5.x3 : Symbol(C5.x3, Decl(file1.ts, 26, 14))
+>c5 : Symbol(c5, Decl(file1.ts, 35, 3))
+>x3 : Symbol(C5.x3, Decl(file1.ts, 26, 14))
+
+c5.x4;
+>c5.x4 : Symbol(C5.x4, Decl(file1.ts, 30, 14))
+>c5 : Symbol(c5, Decl(file1.ts, 35, 3))
+>x4 : Symbol(C5.x4, Decl(file1.ts, 30, 14))
+
+=== tests/cases/conformance/classes/classDeclarations/file2.ts ===
+
+declare class C6 { }
+>C6 : Symbol(C6, Decl(file2.ts, 0, 0), Decl(file3.ts, 0, 0))
+
+interface C7 { }
+>C7 : Symbol(C7, Decl(file2.ts, 1, 20), Decl(file3.ts, 1, 16))
+
+=== tests/cases/conformance/classes/classDeclarations/file3.ts ===
+
+interface C6 { }
+>C6 : Symbol(C6, Decl(file2.ts, 0, 0), Decl(file3.ts, 0, 0))
+
+declare class C7 { }
+>C7 : Symbol(C7, Decl(file2.ts, 1, 20), Decl(file3.ts, 1, 16))
+

tests/baselines/reference/mergedClassInterface.types

@@ -0,0 +1,96 @@
+=== tests/cases/conformance/classes/classDeclarations/file1.ts ===
+
+
+declare class C1 { }
+>C1 : C1
+
+interface C1 { }
+>C1 : C1
+
+interface C2 { }
+>C2 : C2
+
+declare class C2 { }
+>C2 : C2
+
+class C3 { }
+>C3 : C3
+
+interface C3 { }
+>C3 : C3
+
+interface C4 { }
+>C4 : C4
+
+class C4 { }
+>C4 : C4
+
+interface C5 {
+>C5 : C5
+
+    x1: number;
+>x1 : number
+}
+
+declare class C5 {
+>C5 : C5
+
+    x2: number;
+>x2 : number
+}
+
+interface C5 {
+>C5 : C5
+
+    x3: number;
+>x3 : number
+}
+
+interface C5 {
+>C5 : C5
+
+    x4: number;
+>x4 : number
+}
+
+// checks if properties actually were merged
+var c5 : C5;
+>c5 : C5
+>C5 : C5
+
+c5.x1;
+>c5.x1 : number
+>c5 : C5
+>x1 : number
+
+c5.x2;
+>c5.x2 : number
+>c5 : C5
+>x2 : number
+
+c5.x3;
+>c5.x3 : number
+>c5 : C5
+>x3 : number
+
+c5.x4;
+>c5.x4 : number
+>c5 : C5
+>x4 : number
+
+=== tests/cases/conformance/classes/classDeclarations/file2.ts ===
+
+declare class C6 { }
+>C6 : C6
+
+interface C7 { }
+>C7 : C7
+
+=== tests/cases/conformance/classes/classDeclarations/file3.ts ===
+
+interface C6 { }
+>C6 : C6
+
+declare class C7 { }
+>C7 : C7
+

tests/baselines/reference/nameCollisions.errors.txt

@@ -11,13 +11,9 @@ tests/cases/compiler/nameCollisions.ts(33,11): error TS2300: Duplicate identifie
 tests/cases/compiler/nameCollisions.ts(34,14): error TS2300: Duplicate identifier 'C'.
 tests/cases/compiler/nameCollisions.ts(36,14): error TS2300: Duplicate identifier 'C2'.
 tests/cases/compiler/nameCollisions.ts(37,11): error TS2300: Duplicate identifier 'C2'.
-tests/cases/compiler/nameCollisions.ts(42,11): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/nameCollisions.ts(43,15): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/nameCollisions.ts(45,15): error TS2518: Only an ambient class can be merged with an interface.
-tests/cases/compiler/nameCollisions.ts(46,11): error TS2518: Only an ambient class can be merged with an interface.
 
 
-==== tests/cases/compiler/nameCollisions.ts (17 errors) ====
+==== tests/cases/compiler/nameCollisions.ts (13 errors) ====
     module T {
         var x = 2;
             ~
@@ -86,16 +82,8 @@ tests/cases/compiler/nameCollisions.ts(46,11): error TS2518: Only an ambient cla
         interface fi { } // ok
     
         class cli { }
-              ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        interface cli { } // error
-                  ~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+        interface cli { }
     
         interface cli2 { }
-                  ~~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
-        class cli2 { } // error
-              ~~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
+        class cli2 { }
     }

tests/baselines/reference/nameCollisions.js

@@ -41,10 +41,10 @@ module T {
     interface fi { } // ok
 
     class cli { }
-    interface cli { } // error
+    interface cli { }
 
     interface cli2 { }
-    class cli2 { } // error
+    class cli2 { }
 }
 
 //// [nameCollisions.js]
@@ -102,5 +102,5 @@ var T;
         function cli2() {
         }
         return cli2;
-    })(); // error
+    })();
 })(T || (T = {}));

tests/baselines/reference/templateStringsArrayTypeDefinedInES5Mode.errors.txt

@@ -1,13 +1,10 @@
-tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts(2,7): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts(8,3): error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
   Property 'raw' is missing in type '{}'.
 
 
-==== tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts (2 errors) ====
+==== tests/cases/compiler/templateStringsArrayTypeDefinedInES5Mode.ts (1 errors) ====
     
     class TemplateStringsArray {
-          ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     }
     
     function f(x: TemplateStringsArray, y: number, z: number) {

tests/baselines/reference/templateStringsArrayTypeRedefinedInES6Mode.errors.txt

@@ -1,13 +1,10 @@
-tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts(2,7): error TS2518: Only an ambient class can be merged with an interface.
 tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts(8,3): error TS2345: Argument of type '{}' is not assignable to parameter of type 'TemplateStringsArray'.
   Property 'raw' is missing in type '{}'.
 
 
-==== tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts (2 errors) ====
+==== tests/cases/compiler/templateStringsArrayTypeRedefinedInES6Mode.ts (1 errors) ====
     
     class TemplateStringsArray {
-          ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2518: Only an ambient class can be merged with an interface.
     }
     
     function f(x: TemplateStringsArray, y: number, z: number) {

tests/cases/compiler/augmentedTypesClass2.ts

@@ -1,13 +1,13 @@
 // Checking class with other things in type space not value space
 
 // class then interface
-class c11 { // error
+class c11 {
     foo() {
         return 1;
     }
 }
 
-interface c11 { // error
+interface c11 {
     bar(): void;
 }
 

tests/cases/compiler/augmentedTypesInterface.ts

@@ -9,11 +9,11 @@ interface i {
 }
 
 // interface then class
-interface i2 { // error
+interface i2 {
     foo(): void;
 }
 
-class i2 {  // error
+class i2 {
     bar() {
         return 1;
     }

tests/cases/compiler/duplicateIdentifiersAcrossContainerBoundaries.ts

@@ -2,7 +2,7 @@ module M {
     export interface I { }
 }
 module M {
-    export class I { } // error
+    export class I { }
 }
 
 module M {

tests/cases/compiler/interfaceClassMerging.ts

@@ -0,0 +1,39 @@
+interface Foo {
+    method(a: number): string;
+    optionalMethod?(a: number): string;
+    property: string;
+    optionalProperty?: string;
+}
+
+class Foo {
+    additionalProperty: string;
+
+    additionalMethod(a: number): string {
+        return this.method(0);
+    }
+}
+
+class Bar extends Foo {
+    method(a: number) {
+        return this.optionalProperty;
+    }
+}
+
+
+var bar = new Bar();
+bar.method(0);
+bar.optionalMethod(1);
+bar.property;
+bar.optionalProperty;
+bar.additionalProperty;
+bar.additionalMethod(2);
+
+var obj: {
+    method(a: number): string;
+    property: string;
+    additionalProperty: string;
+    additionalMethod(a: number): string;
+};
+
+bar = obj;
+obj = bar;

tests/cases/compiler/interfaceClassMerging2.ts

@@ -0,0 +1,35 @@
+interface Foo {
+    interfaceFooMethod(): this;
+    interfaceFooProperty: this;
+}
+
+class Foo {
+    classFooProperty: this;
+
+    classFooMethod(): this {
+        return this;
+    }
+}
+
+
+interface Bar {
+    interfaceBarMethod(): this;
+    interfaceBarProperty: this;
+}
+
+class Bar extends Foo {
+    classBarProperty: this;
+
+    classBarMethod(): this {
+        return this;
+    }
+}
+
+
+var bar = new Bar();
+bar.interfaceBarMethod().interfaceFooMethod().classBarMethod().classFooMethod();
+
+
+var foo = new Foo();
+
+foo = bar;

tests/cases/compiler/nameCollisions.ts

@@ -40,8 +40,8 @@ module T {
     interface fi { } // ok
 
     class cli { }
-    interface cli { } // error
+    interface cli { }
 
     interface cli2 { }
-    class cli2 { } // error
+    class cli2 { }
 }

tests/cases/conformance/classes/classDeclarations/classAndInterfaceWithSameName.ts

@@ -1,12 +1,12 @@
 class C { foo: string; }
-interface C { foo: string; } // error
+interface C { foo: string; }
 
 module M {
     class D {
         bar: string;
     }
 
-    interface D { // error
+    interface D {
         bar: string;
     }
 }

tests/cases/conformance/classes/classDeclarations/mergedClassInterface.ts

@@ -10,13 +10,13 @@ interface C2 { }
 
 declare class C2 { }
 
-class C3 { } // error -- cannot merge non-ambient class and interface
+class C3 { }
 
-interface C3 { } // error -- cannot merge non-ambient class and interface
+interface C3 { }
 
-interface C4 { } // error -- cannot merge non-ambient class and interface
+interface C4 { }
 
-class C4 { } // error -- cannot merge non-ambient class and interface
+class C4 { }
 
 interface C5 {
     x1: number;