Add conditions to check for class extension or implementation of primitive types like 'number'

Author: qwefgh90

src/compiler/checker.ts

@@ -3791,6 +3791,12 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 if (isExtendedByInterface(errorLocation)) {
                     error(errorLocation, Diagnostics.An_interface_cannot_extend_a_primitive_type_like_0_an_interface_can_only_extend_named_types_and_classes, unescapeLeadingUnderscores(name));
                 }
+                else if (isExtendedByClass(errorLocation)) {
+                    error(errorLocation, Diagnostics.A_class_cannot_extend_a_primitive_type_like_0_a_class_can_only_extend_named_types_and_classes, unescapeLeadingUnderscores(name));
+                }
+                else if (isImplementedByClass(errorLocation)) {
+                    error(errorLocation, Diagnostics.A_class_cannot_implement_a_primitive_type_like_0_a_class_can_only_implement_interfaces, unescapeLeadingUnderscores(name));
+                }
                 else {
                     error(errorLocation, Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here, unescapeLeadingUnderscores(name));
                 }
@@ -3826,6 +3832,28 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         return false;
     }
 
+    function isExtendedByClass(node: Node): boolean {
+        const grandparent = node.parent.parent;
+        const parentOfGrandparent = grandparent.parent;
+        if(grandparent && parentOfGrandparent){
+            const isExtending = isHeritageClause(grandparent) && grandparent.token === SyntaxKind.ExtendsKeyword;
+            const isClass = isClassDeclaration(parentOfGrandparent);
+            return isExtending && isClass;
+        }
+        return false;
+    }
+
+    function isImplementedByClass(node: Node): boolean {
+        const grandparent = node.parent.parent;
+        const parentOfGrandparent = grandparent.parent;
+        if(grandparent && parentOfGrandparent){
+            const isImplementing = isHeritageClause(grandparent) && grandparent.token === SyntaxKind.ImplementsKeyword;
+            const isClass = isClassDeclaration(parentOfGrandparent);
+            return isImplementing && isClass;
+        }
+        return false;
+    }
+
     function maybeMappedType(node: Node, symbol: Symbol) {
         const container = findAncestor(node.parent, n => isComputedPropertyName(n) || isPropertySignature(n) ? false : isTypeLiteralNode(n) || "quit") as TypeLiteralNode | undefined;
         if (container && container.members.length === 1) {

src/compiler/diagnosticMessages.json

@@ -3619,7 +3619,7 @@
         "category": "Error",
         "code": 2839
     },
-    "An interface cannot extend a primitive type like '{0}'; an interface can only extend named types and classes": {
+    "An interface cannot extend a primitive type like '{0}'; an interface can only extend named types and classes.": {
         "category": "Error",
         "code": 2840
     },
@@ -3699,6 +3699,14 @@
         "category": "Error",
         "code": 2861
     },
+    "A class cannot extend a primitive type like '{0}'; a class can only extend named types and classes.": {
+        "category": "Error",
+        "code": 2862
+    },
+    "A class cannot implement a primitive type like '{0}'; a class can only implement interfaces.": {
+        "category": "Error",
+        "code": 2863
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

tests/baselines/reference/classExtendingPrimitive.errors.txt

@@ -1,6 +1,6 @@
-classExtendingPrimitive.ts(3,17): error TS2693: 'number' only refers to a type, but is being used as a value here.
-classExtendingPrimitive.ts(4,18): error TS2693: 'string' only refers to a type, but is being used as a value here.
-classExtendingPrimitive.ts(5,18): error TS2693: 'boolean' only refers to a type, but is being used as a value here.
+classExtendingPrimitive.ts(3,17): error TS2855: A class cannot extend a primitive type like 'number'; a class can only extend named types and classes.
+classExtendingPrimitive.ts(4,18): error TS2855: A class cannot extend a primitive type like 'string'; a class can only extend named types and classes.
+classExtendingPrimitive.ts(5,18): error TS2855: A class cannot extend a primitive type like 'boolean'; a class can only extend named types and classes.
 classExtendingPrimitive.ts(6,18): error TS2304: Cannot find name 'Void'.
 classExtendingPrimitive.ts(7,19): error TS1109: Expression expected.
 classExtendingPrimitive.ts(8,18): error TS2304: Cannot find name 'Null'.
@@ -14,13 +14,13 @@ classExtendingPrimitive.ts(14,18): error TS2507: Type 'typeof E' is not a constr
 
     class C extends number { }
                     ~~~~~~
-!!! error TS2693: 'number' only refers to a type, but is being used as a value here.
+!!! error TS2855: A class cannot extend a primitive type like 'number'; a class can only extend named types and classes.
     class C2 extends string { }
                      ~~~~~~
-!!! error TS2693: 'string' only refers to a type, but is being used as a value here.
+!!! error TS2855: A class cannot extend a primitive type like 'string'; a class can only extend named types and classes.
     class C3 extends boolean { }
                      ~~~~~~~
-!!! error TS2693: 'boolean' only refers to a type, but is being used as a value here.
+!!! error TS2855: A class cannot extend a primitive type like 'boolean'; a class can only extend named types and classes.
     class C4 extends Void  { }
                      ~~~~
 !!! error TS2304: Cannot find name 'Void'.

tests/baselines/reference/classImplementsPrimitive.errors.txt

@@ -0,0 +1,68 @@
+classImplementsPrimitive.ts(3,20): error TS2856: A class cannot implement a primitive type like 'number'; a class can only implement interfaces.
+classImplementsPrimitive.ts(4,21): error TS2856: A class cannot implement a primitive type like 'string'; a class can only implement interfaces.
+classImplementsPrimitive.ts(5,21): error TS2856: A class cannot implement a primitive type like 'boolean'; a class can only implement interfaces.
+classImplementsPrimitive.ts(6,21): error TS2304: Cannot find name 'Void'.
+classImplementsPrimitive.ts(7,7): error TS2300: Duplicate identifier 'C4a'.
+classImplementsPrimitive.ts(7,22): error TS1109: Expression expected.
+classImplementsPrimitive.ts(8,21): error TS2304: Cannot find name 'Null'.
+classImplementsPrimitive.ts(9,7): error TS2300: Duplicate identifier 'C5a'.
+classImplementsPrimitive.ts(9,22): error TS2500: A class can only implement an identifier/qualified-name with optional type arguments.
+classImplementsPrimitive.ts(10,21): error TS2749: 'undefined' refers to a value, but is being used as a type here. Did you mean 'typeof undefined'?
+classImplementsPrimitive.ts(11,21): error TS2304: Cannot find name 'Undefined'.
+classImplementsPrimitive.ts(14,21): error TS2422: A class can only implement an object type or intersection of object types with statically known members.
+classImplementsPrimitive.ts(16,7): error TS2300: Duplicate identifier 'C4a'.
+classImplementsPrimitive.ts(16,22): error TS1109: Expression expected.
+classImplementsPrimitive.ts(17,7): error TS2300: Duplicate identifier 'C5a'.
+classImplementsPrimitive.ts(17,22): error TS2500: A class can only implement an identifier/qualified-name with optional type arguments.
+
+
+==== classImplementsPrimitive.ts (16 errors) ====
+    // classes cannot implement primitives
+    
+    class C implements number { }
+                       ~~~~~~
+!!! error TS2856: A class cannot implement a primitive type like 'number'; a class can only implement interfaces.
+    class C2 implements string { }
+                        ~~~~~~
+!!! error TS2856: A class cannot implement a primitive type like 'string'; a class can only implement interfaces.
+    class C3 implements boolean { }
+                        ~~~~~~~
+!!! error TS2856: A class cannot implement a primitive type like 'boolean'; a class can only implement interfaces.
+    class C4 implements Void  { }
+                        ~~~~
+!!! error TS2304: Cannot find name 'Void'.
+    class C4a implements void {}
+          ~~~
+!!! error TS2300: Duplicate identifier 'C4a'.
+                         ~~~~
+!!! error TS1109: Expression expected.
+    class C5 implements Null { }
+                        ~~~~
+!!! error TS2304: Cannot find name 'Null'.
+    class C5a implements null { }
+          ~~~
+!!! error TS2300: Duplicate identifier 'C5a'.
+                         ~~~~
+!!! error TS2500: A class can only implement an identifier/qualified-name with optional type arguments.
+    class C6 implements undefined { }
+                        ~~~~~~~~~
+!!! error TS2749: 'undefined' refers to a value, but is being used as a type here. Did you mean 'typeof undefined'?
+    class C7 implements Undefined { }
+                        ~~~~~~~~~
+!!! error TS2304: Cannot find name 'Undefined'.
+    
+    enum E { A }
+    class C8 implements E { }
+                        ~
+!!! error TS2422: A class can only implement an object type or intersection of object types with statically known members.
+    
+    class C4a implements void {}
+          ~~~
+!!! error TS2300: Duplicate identifier 'C4a'.
+                         ~~~~
+!!! error TS1109: Expression expected.
+    class C5a implements null { }
+          ~~~
+!!! error TS2300: Duplicate identifier 'C5a'.
+                         ~~~~
+!!! error TS2500: A class can only implement an identifier/qualified-name with optional type arguments.

tests/baselines/reference/classImplementsPrimitive.js

@@ -0,0 +1,89 @@
+//// [tests/cases/compiler/classImplementsPrimitive.ts] ////
+
+//// [classImplementsPrimitive.ts]
+// classes cannot implement primitives
+
+class C implements number { }
+class C2 implements string { }
+class C3 implements boolean { }
+class C4 implements Void  { }
+class C4a implements void {}
+class C5 implements Null { }
+class C5a implements null { }
+class C6 implements undefined { }
+class C7 implements Undefined { }
+
+enum E { A }
+class C8 implements E { }
+
+class C4a implements void {}
+class C5a implements null { }
+
+//// [classImplementsPrimitive.js]
+// classes cannot implement primitives
+var C = /** @class */ (function () {
+    function C() {
+    }
+    return C;
+}());
+var C2 = /** @class */ (function () {
+    function C2() {
+    }
+    return C2;
+}());
+var C3 = /** @class */ (function () {
+    function C3() {
+    }
+    return C3;
+}());
+var C4 = /** @class */ (function () {
+    function C4() {
+    }
+    return C4;
+}());
+var C4a = /** @class */ (function () {
+    function C4a() {
+    }
+    return C4a;
+}());
+void {};
+var C5 = /** @class */ (function () {
+    function C5() {
+    }
+    return C5;
+}());
+var C5a = /** @class */ (function () {
+    function C5a() {
+    }
+    return C5a;
+}());
+var C6 = /** @class */ (function () {
+    function C6() {
+    }
+    return C6;
+}());
+var C7 = /** @class */ (function () {
+    function C7() {
+    }
+    return C7;
+}());
+var E;
+(function (E) {
+    E[E["A"] = 0] = "A";
+})(E || (E = {}));
+var C8 = /** @class */ (function () {
+    function C8() {
+    }
+    return C8;
+}());
+var C4a = /** @class */ (function () {
+    function C4a() {
+    }
+    return C4a;
+}());
+void {};
+var C5a = /** @class */ (function () {
+    function C5a() {
+    }
+    return C5a;
+}());

tests/baselines/reference/classImplementsPrimitive.symbols

@@ -0,0 +1,46 @@
+//// [tests/cases/compiler/classImplementsPrimitive.ts] ////
+
+=== classImplementsPrimitive.ts ===
+// classes cannot implement primitives
+
+class C implements number { }
+>C : Symbol(C, Decl(classImplementsPrimitive.ts, 0, 0))
+
+class C2 implements string { }
+>C2 : Symbol(C2, Decl(classImplementsPrimitive.ts, 2, 29))
+
+class C3 implements boolean { }
+>C3 : Symbol(C3, Decl(classImplementsPrimitive.ts, 3, 30))
+
+class C4 implements Void  { }
+>C4 : Symbol(C4, Decl(classImplementsPrimitive.ts, 4, 31))
+
+class C4a implements void {}
+>C4a : Symbol(C4a, Decl(classImplementsPrimitive.ts, 5, 29))
+
+class C5 implements Null { }
+>C5 : Symbol(C5, Decl(classImplementsPrimitive.ts, 6, 28))
+
+class C5a implements null { }
+>C5a : Symbol(C5a, Decl(classImplementsPrimitive.ts, 7, 28))
+
+class C6 implements undefined { }
+>C6 : Symbol(C6, Decl(classImplementsPrimitive.ts, 8, 29))
+
+class C7 implements Undefined { }
+>C7 : Symbol(C7, Decl(classImplementsPrimitive.ts, 9, 33))
+
+enum E { A }
+>E : Symbol(E, Decl(classImplementsPrimitive.ts, 10, 33))
+>A : Symbol(E.A, Decl(classImplementsPrimitive.ts, 12, 8))
+
+class C8 implements E { }
+>C8 : Symbol(C8, Decl(classImplementsPrimitive.ts, 12, 12))
+>E : Symbol(E, Decl(classImplementsPrimitive.ts, 10, 33))
+
+class C4a implements void {}
+>C4a : Symbol(C4a, Decl(classImplementsPrimitive.ts, 13, 25))
+
+class C5a implements null { }
+>C5a : Symbol(C5a, Decl(classImplementsPrimitive.ts, 15, 28))
+

tests/baselines/reference/classImplementsPrimitive.types

@@ -0,0 +1,49 @@
+//// [tests/cases/compiler/classImplementsPrimitive.ts] ////
+
+=== classImplementsPrimitive.ts ===
+// classes cannot implement primitives
+
+class C implements number { }
+>C : C
+
+class C2 implements string { }
+>C2 : C2
+
+class C3 implements boolean { }
+>C3 : C3
+
+class C4 implements Void  { }
+>C4 : C4
+
+class C4a implements void {}
+>C4a : C4a
+>void {} : undefined
+>{} : {}
+
+class C5 implements Null { }
+>C5 : C5
+
+class C5a implements null { }
+>C5a : C5a
+
+class C6 implements undefined { }
+>C6 : C6
+
+class C7 implements Undefined { }
+>C7 : C7
+
+enum E { A }
+>E : E
+>A : E.A
+
+class C8 implements E { }
+>C8 : C8
+
+class C4a implements void {}
+>C4a : C4a
+>void {} : undefined
+>{} : {}
+
+class C5a implements null { }
+>C5a : C5a
+

tests/baselines/reference/errorLocationForInterfaceExtension.errors.txt

@@ -1,10 +1,10 @@
-errorLocationForInterfaceExtension.ts(3,21): error TS2840: An interface cannot extend a primitive type like 'string'; an interface can only extend named types and classes
+errorLocationForInterfaceExtension.ts(3,21): error TS2840: An interface cannot extend a primitive type like 'string'; an interface can only extend named types and classes.
 
 
 ==== errorLocationForInterfaceExtension.ts (1 errors) ====
     var n = '';
 
     interface x extends string { }
                         ~~~~~~
-!!! error TS2840: An interface cannot extend a primitive type like 'string'; an interface can only extend named types and classes
+!!! error TS2840: An interface cannot extend a primitive type like 'string'; an interface can only extend named types and classes.
 

tests/baselines/reference/interfacedeclWithIndexerErrors.errors.txt

@@ -3,7 +3,7 @@ interfacedeclWithIndexerErrors.ts(14,5): error TS2411: Property 'p4' of type 'nu
 interfacedeclWithIndexerErrors.ts(15,5): error TS2411: Property 'p5' of type '(s: number) => string' is not assignable to 'string' index type '() => string'.
 interfacedeclWithIndexerErrors.ts(19,5): error TS2411: Property 'f3' of type '(a: string) => number' is not assignable to 'string' index type '() => string'.
 interfacedeclWithIndexerErrors.ts(20,5): error TS2411: Property 'f4' of type '(s: number) => string' is not assignable to 'string' index type '() => string'.
-interfacedeclWithIndexerErrors.ts(44,21): error TS2840: An interface cannot extend a primitive type like 'number'; an interface can only extend named types and classes
+interfacedeclWithIndexerErrors.ts(44,21): error TS2840: An interface cannot extend a primitive type like 'number'; an interface can only extend named types and classes.
 interfacedeclWithIndexerErrors.ts(48,18): error TS2693: 'string' only refers to a type, but is being used as a value here.
 
 
@@ -63,7 +63,7 @@ interfacedeclWithIndexerErrors.ts(48,18): error TS2693: 'string' only refers to
 
     interface e extends number {
                         ~~~~~~
-!!! error TS2840: An interface cannot extend a primitive type like 'number'; an interface can only extend named types and classes
+!!! error TS2840: An interface cannot extend a primitive type like 'number'; an interface can only extend named types and classes.
     }
 
     interface f {

tests/baselines/reference/topLevelAwaitErrors.1(module=es2022).errors.txt

@@ -6,7 +6,7 @@ topLevelAwaitErrors.1.ts(8,14): error TS1005: '>' expected.
 topLevelAwaitErrors.1.ts(8,16): error TS2693: 'string' only refers to a type, but is being used as a value here.
 topLevelAwaitErrors.1.ts(11,17): error TS1109: Expression expected.
 topLevelAwaitErrors.1.ts(11,22): error TS1109: Expression expected.
-topLevelAwaitErrors.1.ts(11,23): error TS2693: 'string' only refers to a type, but is being used as a value here.
+topLevelAwaitErrors.1.ts(11,23): error TS2855: A class cannot extend a primitive type like 'string'; a class can only extend named types and classes.
 topLevelAwaitErrors.1.ts(11,29): error TS1005: ',' expected.
 topLevelAwaitErrors.1.ts(15,8): error TS1109: Expression expected.
 topLevelAwaitErrors.1.ts(18,2): error TS1109: Expression expected.
@@ -49,7 +49,7 @@ topLevelAwaitErrors.1.ts(42,20): error TS1109: Expression expected.
                          ~
 !!! error TS1109: Expression expected.
                           ~~~~~~
-!!! error TS2693: 'string' only refers to a type, but is being used as a value here.
+!!! error TS2855: A class cannot extend a primitive type like 'string'; a class can only extend named types and classes.
                                 ~
 !!! error TS1005: ',' expected.
     }