Merge pull request microsoft#19797 from charlespierce/implements_clas…

…s_error_message

Add new error message when class implements class

src/compiler/checker.ts

@@ -22740,7 +22740,12 @@ namespace ts {
                         const t = getTypeFromTypeNode(typeRefNode);
                         if (t !== unknownType) {
                             if (isValidBaseType(t)) {
-                                checkTypeAssignableTo(typeWithThis, getTypeWithThisArgument(t, type.thisType), node.name || node, Diagnostics.Class_0_incorrectly_implements_interface_1);
+                                checkTypeAssignableTo(typeWithThis,
+                                    getTypeWithThisArgument(t, type.thisType),
+                                    node.name || node,
+                                    t.symbol.flags & SymbolFlags.Class ?
+                                        Diagnostics.Class_0_incorrectly_implements_class_1_Did_you_mean_to_extend_1_and_inherit_its_members_as_a_subclass :
+                                        Diagnostics.Class_0_incorrectly_implements_interface_1);
                             }
                             else {
                                 error(typeRefNode, Diagnostics.A_class_may_only_implement_another_class_or_interface);

src/compiler/diagnosticMessages.json

@@ -2276,6 +2276,10 @@
         "category": "Error",
         "code": 2719
     },
+    "Class '{0}' incorrectly implements class '{1}'. Did you mean to extend '{1}' and inherit its members as a subclass?": {
+        "category": "Error",
+        "code": 2720
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/services/codefixes/fixClassIncorrectlyImplementsInterface.ts

@@ -1,6 +1,7 @@
 /* @internal */
 namespace ts.codefix {
-    const errorCodes = [Diagnostics.Class_0_incorrectly_implements_interface_1.code];
+    const errorCodes = [Diagnostics.Class_0_incorrectly_implements_interface_1.code,
+                        Diagnostics.Class_0_incorrectly_implements_class_1_Did_you_mean_to_extend_1_and_inherit_its_members_as_a_subclass.code];
     const fixId = "fixClassIncorrectlyImplementsInterface"; // TODO: share a group with fixClassDoesntImplementInheritedAbstractMember?
     registerCodeFix({
         errorCodes,

tests/baselines/reference/classImplementsClass2.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/classImplementsClass2.ts(2,7): error TS2420: Class 'C' incorrectly implements interface 'A'.
+tests/cases/compiler/classImplementsClass2.ts(2,7): error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
   Property 'foo' is missing in type 'C'.
 tests/cases/compiler/classImplementsClass2.ts(13,1): error TS2322: Type 'C' is not assignable to type 'C2'.
   Property 'foo' is missing in type 'C'.
@@ -8,8 +8,8 @@ tests/cases/compiler/classImplementsClass2.ts(13,1): error TS2322: Type 'C' is n
     class A { foo(): number { return 1; } }
     class C implements A {} // error
           ~
-!!! error TS2420: Class 'C' incorrectly implements interface 'A'.
-!!! error TS2420:   Property 'foo' is missing in type 'C'.
+!!! error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
+!!! error TS2720:   Property 'foo' is missing in type 'C'.
 
     class C2 extends A {
         foo() {

tests/baselines/reference/classImplementsClass4.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/classImplementsClass4.ts(5,7): error TS2420: Class 'C' incorrectly implements interface 'A'.
+tests/cases/compiler/classImplementsClass4.ts(5,7): error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
   Property 'x' is missing in type 'C'.
 tests/cases/compiler/classImplementsClass4.ts(16,1): error TS2322: Type 'C' is not assignable to type 'C2'.
   Property 'x' is missing in type 'C'.
@@ -11,8 +11,8 @@ tests/cases/compiler/classImplementsClass4.ts(16,1): error TS2322: Type 'C' is n
     }
     class C implements A {
           ~
-!!! error TS2420: Class 'C' incorrectly implements interface 'A'.
-!!! error TS2420:   Property 'x' is missing in type 'C'.
+!!! error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
+!!! error TS2720:   Property 'x' is missing in type 'C'.
         foo() {
             return 1;
         }

tests/baselines/reference/classImplementsClass5.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/classImplementsClass5.ts(5,7): error TS2420: Class 'C' incorrectly implements interface 'A'.
+tests/cases/compiler/classImplementsClass5.ts(5,7): error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
   Types have separate declarations of a private property 'x'.
 tests/cases/compiler/classImplementsClass5.ts(16,1): error TS2322: Type 'C2' is not assignable to type 'C'.
   Types have separate declarations of a private property 'x'.
@@ -13,8 +13,8 @@ tests/cases/compiler/classImplementsClass5.ts(17,1): error TS2322: Type 'C' is n
     }
     class C implements A {
           ~
-!!! error TS2420: Class 'C' incorrectly implements interface 'A'.
-!!! error TS2420:   Types have separate declarations of a private property 'x'.
+!!! error TS2720: Class 'C' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
+!!! error TS2720:   Types have separate declarations of a private property 'x'.
         private x = 1;
         foo() {
             return 1;

tests/baselines/reference/classImplementsClass7.errors.txt

@@ -0,0 +1,14 @@
+tests/cases/compiler/classImplementsClass7.ts(5,7): error TS2720: Class 'B' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
+  Property 'x' is missing in type 'B'.
+
+
+==== tests/cases/compiler/classImplementsClass7.ts (1 errors) ====
+    class A {
+        private x: number;
+    }
+
+    class B implements A {}
+          ~
+!!! error TS2720: Class 'B' incorrectly implements class 'A'. Did you mean to extend 'A' and inherit its members as a subclass?
+!!! error TS2720:   Property 'x' is missing in type 'B'.
+

tests/baselines/reference/classImplementsClass7.js

@@ -0,0 +1,19 @@
+//// [classImplementsClass7.ts]
+class A {
+    private x: number;
+}
+
+class B implements A {}
+
+
+//// [classImplementsClass7.js]
+var A = /** @class */ (function () {
+    function A() {
+    }
+    return A;
+}());
+var B = /** @class */ (function () {
+    function B() {
+    }
+    return B;
+}());

tests/baselines/reference/classImplementsClass7.symbols

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/classImplementsClass7.ts ===
+class A {
+>A : Symbol(A, Decl(classImplementsClass7.ts, 0, 0))
+
+    private x: number;
+>x : Symbol(A.x, Decl(classImplementsClass7.ts, 0, 9))
+}
+
+class B implements A {}
+>B : Symbol(B, Decl(classImplementsClass7.ts, 2, 1))
+>A : Symbol(A, Decl(classImplementsClass7.ts, 0, 0))
+

tests/baselines/reference/classImplementsClass7.types

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/classImplementsClass7.ts ===
+class A {
+>A : A
+
+    private x: number;
+>x : number
+}
+
+class B implements A {}
+>B : B
+>A : A
+

tests/baselines/reference/classImplementsMergedClassInterface.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInterface.ts(9,7): error TS2420: Class 'C2' incorrectly implements interface 'C1'.
+tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInterface.ts(9,7): error TS2720: Class 'C2' incorrectly implements class 'C1'. Did you mean to extend 'C1' and inherit its members as a subclass?
   Property 'x' is missing in type 'C2'.
-tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInterface.ts(12,7): error TS2420: Class 'C3' incorrectly implements interface 'C1'.
+tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInterface.ts(12,7): error TS2720: Class 'C3' incorrectly implements class 'C1'. Did you mean to extend 'C1' and inherit its members as a subclass?
   Property 'y' is missing in type 'C3'.
-tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInterface.ts(16,7): error TS2420: Class 'C4' incorrectly implements interface 'C1'.
+tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInterface.ts(16,7): error TS2720: Class 'C4' incorrectly implements class 'C1'. Did you mean to extend 'C1' and inherit its members as a subclass?
   Property 'x' is missing in type 'C4'.
 
 
@@ -17,21 +17,21 @@ tests/cases/conformance/classes/classDeclarations/classImplementsMergedClassInte
 
     class C2 implements C1 { // error -- missing x
           ~~
-!!! error TS2420: Class 'C2' incorrectly implements interface 'C1'.
-!!! error TS2420:   Property 'x' is missing in type 'C2'.
+!!! error TS2720: Class 'C2' incorrectly implements class 'C1'. Did you mean to extend 'C1' and inherit its members as a subclass?
+!!! error TS2720:   Property 'x' is missing in type 'C2'.
     }
 
     class C3 implements C1 { // error -- missing y
           ~~
-!!! error TS2420: Class 'C3' incorrectly implements interface 'C1'.
-!!! error TS2420:   Property 'y' is missing in type 'C3'.
+!!! error TS2720: Class 'C3' incorrectly implements class 'C1'. Did you mean to extend 'C1' and inherit its members as a subclass?
+!!! error TS2720:   Property 'y' is missing in type 'C3'.
         x : number;
     }
 
     class C4 implements C1 { // error -- missing x
           ~~
-!!! error TS2420: Class 'C4' incorrectly implements interface 'C1'.
-!!! error TS2420:   Property 'x' is missing in type 'C4'.
+!!! error TS2720: Class 'C4' incorrectly implements class 'C1'. Did you mean to extend 'C1' and inherit its members as a subclass?
+!!! error TS2720:   Property 'x' is missing in type 'C4'.
         y : number;
     }
 

tests/baselines/reference/extendAndImplementTheSameBaseType2.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/extendAndImplementTheSameBaseType2.ts(7,7): error TS2420: Class 'D' incorrectly implements interface 'C<number>'.
+tests/cases/compiler/extendAndImplementTheSameBaseType2.ts(7,7): error TS2720: Class 'D' incorrectly implements class 'C<number>'. Did you mean to extend 'C<number>' and inherit its members as a subclass?
   Types of property 'bar' are incompatible.
     Type '() => string' is not assignable to type '() => number'.
       Type 'string' is not assignable to type 'number'.
@@ -15,10 +15,10 @@ tests/cases/compiler/extendAndImplementTheSameBaseType2.ts(16,5): error TS2322:
     }
     class D extends C<string> implements C<number> {
           ~
-!!! error TS2420: Class 'D' incorrectly implements interface 'C<number>'.
-!!! error TS2420:   Types of property 'bar' are incompatible.
-!!! error TS2420:     Type '() => string' is not assignable to type '() => number'.
-!!! error TS2420:       Type 'string' is not assignable to type 'number'.
+!!! error TS2720: Class 'D' incorrectly implements class 'C<number>'. Did you mean to extend 'C<number>' and inherit its members as a subclass?
+!!! error TS2720:   Types of property 'bar' are incompatible.
+!!! error TS2720:     Type '() => string' is not assignable to type '() => number'.
+!!! error TS2720:       Type 'string' is not assignable to type 'number'.
         baz() { }
     }
 

tests/baselines/reference/genericSpecializations2.errors.txt

@@ -1,10 +1,10 @@
-tests/cases/compiler/genericSpecializations2.ts(7,7): error TS2420: Class 'IntFooBad' incorrectly implements interface 'IFoo<number>'.
+tests/cases/compiler/genericSpecializations2.ts(7,7): error TS2720: Class 'IntFooBad' incorrectly implements class 'IFoo<number>'. Did you mean to extend 'IFoo<number>' and inherit its members as a subclass?
   Types of property 'foo' are incompatible.
     Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
       Types of parameters 'x' and 'x' are incompatible.
         Type 'T' is not assignable to type 'string'.
 tests/cases/compiler/genericSpecializations2.ts(8,9): error TS2368: Type parameter name cannot be 'string'.
-tests/cases/compiler/genericSpecializations2.ts(11,7): error TS2420: Class 'StringFoo2' incorrectly implements interface 'IFoo<string>'.
+tests/cases/compiler/genericSpecializations2.ts(11,7): error TS2720: Class 'StringFoo2' incorrectly implements class 'IFoo<string>'. Did you mean to extend 'IFoo<string>' and inherit its members as a subclass?
   Types of property 'foo' are incompatible.
     Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
       Types of parameters 'x' and 'x' are incompatible.
@@ -21,23 +21,23 @@ tests/cases/compiler/genericSpecializations2.ts(12,9): error TS2368: Type parame
 
     class IntFooBad implements IFoo<number> {
           ~~~~~~~~~
-!!! error TS2420: Class 'IntFooBad' incorrectly implements interface 'IFoo<number>'.
-!!! error TS2420:   Types of property 'foo' are incompatible.
-!!! error TS2420:     Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
-!!! error TS2420:       Types of parameters 'x' and 'x' are incompatible.
-!!! error TS2420:         Type 'T' is not assignable to type 'string'.
+!!! error TS2720: Class 'IntFooBad' incorrectly implements class 'IFoo<number>'. Did you mean to extend 'IFoo<number>' and inherit its members as a subclass?
+!!! error TS2720:   Types of property 'foo' are incompatible.
+!!! error TS2720:     Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
+!!! error TS2720:       Types of parameters 'x' and 'x' are incompatible.
+!!! error TS2720:         Type 'T' is not assignable to type 'string'.
         foo<string>(x: string): string { return null; }
             ~~~~~~
 !!! error TS2368: Type parameter name cannot be 'string'.
     }
 
     class StringFoo2 implements IFoo<string> {
           ~~~~~~~~~~
-!!! error TS2420: Class 'StringFoo2' incorrectly implements interface 'IFoo<string>'.
-!!! error TS2420:   Types of property 'foo' are incompatible.
-!!! error TS2420:     Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
-!!! error TS2420:       Types of parameters 'x' and 'x' are incompatible.
-!!! error TS2420:         Type 'T' is not assignable to type 'string'.
+!!! error TS2720: Class 'StringFoo2' incorrectly implements class 'IFoo<string>'. Did you mean to extend 'IFoo<string>' and inherit its members as a subclass?
+!!! error TS2720:   Types of property 'foo' are incompatible.
+!!! error TS2720:     Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
+!!! error TS2720:       Types of parameters 'x' and 'x' are incompatible.
+!!! error TS2720:         Type 'T' is not assignable to type 'string'.
         foo<string>(x: string): string { return null; }
             ~~~~~~
 !!! error TS2368: Type parameter name cannot be 'string'.

tests/cases/compiler/classImplementsClass7.ts

@@ -0,0 +1,5 @@
+class A {
+    private x: number;
+}
+
+class B implements A {}