Offer per-member diagnostics for incorrectly implemented inherited members (#21036)

* Offer per-member diagnostics for incorrectly implemented inherited members on classes

* Revise error message, make containingChain a thunk

* Fix typo in comment

Author: weswigham

src/compiler/checker.ts

@@ -9169,15 +9169,15 @@ namespace ts {
             return isTypeComparableTo(type1, type2) || isTypeComparableTo(type2, type1);
         }
 
-        function checkTypeAssignableTo(source: Type, target: Type, errorNode: Node, headMessage?: DiagnosticMessage, containingMessageChain?: DiagnosticMessageChain): boolean {
+        function checkTypeAssignableTo(source: Type, target: Type, errorNode: Node, headMessage?: DiagnosticMessage, containingMessageChain?: () => DiagnosticMessageChain | undefined): boolean {
             return checkTypeRelatedTo(source, target, assignableRelation, errorNode, headMessage, containingMessageChain);
         }
 
         /**
          * This is *not* a bi-directional relationship.
          * If one needs to check both directions for comparability, use a second call to this function or 'isTypeComparableTo'.
          */
-        function checkTypeComparableTo(source: Type, target: Type, errorNode: Node, headMessage?: DiagnosticMessage, containingMessageChain?: DiagnosticMessageChain): boolean {
+        function checkTypeComparableTo(source: Type, target: Type, errorNode: Node, headMessage?: DiagnosticMessage, containingMessageChain?: () => DiagnosticMessageChain | undefined): boolean {
             return checkTypeRelatedTo(source, target, comparableRelation, errorNode, headMessage, containingMessageChain);
         }
 
@@ -9511,7 +9511,7 @@ namespace ts {
             relation: Map<RelationComparisonResult>,
             errorNode: Node,
             headMessage?: DiagnosticMessage,
-            containingMessageChain?: DiagnosticMessageChain): boolean {
+            containingMessageChain?: () => DiagnosticMessageChain | undefined): boolean {
 
             let errorInfo: DiagnosticMessageChain;
             let maybeKeys: string[];
@@ -9531,7 +9531,10 @@ namespace ts {
             }
             else if (errorInfo) {
                 if (containingMessageChain) {
-                    errorInfo = concatenateDiagnosticMessageChains(containingMessageChain, errorInfo);
+                    const chain = containingMessageChain();
+                    if (chain) {
+                        errorInfo = concatenateDiagnosticMessageChains(chain, errorInfo);
+                    }
                 }
 
                 diagnostics.add(createDiagnosticForNodeFromMessageChain(errorNode, errorInfo));
@@ -16675,7 +16678,7 @@ namespace ts {
                 const constraint = getConstraintOfTypeParameter(typeParameters[i]);
                 if (!constraint) continue;
 
-                const errorInfo = reportErrors && headMessage && chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Type_0_does_not_satisfy_the_constraint_1);
+                const errorInfo = reportErrors && headMessage && (() => chainDiagnosticMessages(/*details*/ undefined, Diagnostics.Type_0_does_not_satisfy_the_constraint_1));
                 const typeArgumentHeadMessage = headMessage || Diagnostics.Type_0_does_not_satisfy_the_constraint_1;
                 if (!mapper) {
                     mapper = createTypeMapper(typeParameters, typeArgumentTypes);
@@ -19697,7 +19700,7 @@ namespace ts {
                             Diagnostics.A_type_predicate_cannot_reference_a_rest_parameter);
                     }
                     else {
-                        const leadingError = chainDiagnosticMessages(/*details*/ undefined, Diagnostics.A_type_predicate_s_type_must_be_assignable_to_its_parameter_s_type);
+                        const leadingError = () => chainDiagnosticMessages(/*details*/ undefined, Diagnostics.A_type_predicate_s_type_must_be_assignable_to_its_parameter_s_type);
                         checkTypeAssignableTo(typePredicate.type,
                             getTypeOfNode(parent.parameters[typePredicate.parameterIndex]),
                             node.type,
@@ -20984,7 +20987,7 @@ namespace ts {
                 expectedReturnType,
                 node,
                 headMessage,
-                errorInfo);
+                () => errorInfo);
         }
 
         /**
@@ -22907,7 +22910,10 @@ namespace ts {
                             }
                         }
                     }
-                    checkTypeAssignableTo(typeWithThis, getTypeWithThisArgument(baseType, type.thisType), node.name || node, Diagnostics.Class_0_incorrectly_extends_base_class_1);
+                    const baseWithThis = getTypeWithThisArgument(baseType, type.thisType);
+                    if (!checkTypeAssignableTo(typeWithThis, baseWithThis, /*errorNode*/ undefined)) {
+                        issueMemberSpecificError(node, typeWithThis, baseWithThis, Diagnostics.Class_0_incorrectly_extends_base_class_1);
+                    }
                     checkTypeAssignableTo(staticType, getTypeWithoutSignatures(staticBaseType), node.name || node,
                         Diagnostics.Class_static_side_0_incorrectly_extends_base_class_static_side_1);
                     if (baseConstructorType.flags & TypeFlags.TypeVariable && !isMixinConstructorType(staticType)) {
@@ -22939,12 +22945,13 @@ namespace ts {
                         const t = getTypeFromTypeNode(typeRefNode);
                         if (t !== unknownType) {
                             if (isValidBaseType(t)) {
-                                checkTypeAssignableTo(typeWithThis,
-                                    getTypeWithThisArgument(t, type.thisType),
-                                    node.name || node,
-                                    t.symbol && 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);
+                                const genericDiag = t.symbol && 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;
+                                const baseWithThis = getTypeWithThisArgument(t, type.thisType);
+                                if (!checkTypeAssignableTo(typeWithThis, baseWithThis, /*errorNode*/ undefined)) {
+                                    issueMemberSpecificError(node, typeWithThis, baseWithThis, genericDiag);
+                                }
                             }
                             else {
                                 error(typeRefNode, Diagnostics.A_class_may_only_implement_another_class_or_interface);
@@ -22961,6 +22968,37 @@ namespace ts {
             }
         }
 
+        function issueMemberSpecificError(node: ClassLikeDeclaration, typeWithThis: Type, baseWithThis: Type, broadDiag: DiagnosticMessage) {
+            // iterate over all implemented properties and issue errors on each one which isn't compatible, rather than the class as a whole, if possible
+            let issuedMemberError = false;
+            for (const member of node.members) {
+                if (hasStaticModifier(member)) {
+                    continue;
+                }
+                const declaredProp = member.name && getSymbolAtLocation(member.name) || getSymbolAtLocation(member);
+                if (declaredProp) {
+                    const prop = getPropertyOfType(typeWithThis, declaredProp.escapedName);
+                    const baseProp = getPropertyOfType(baseWithThis, declaredProp.escapedName);
+                    if (prop && baseProp) {
+                        const rootChain = () => chainDiagnosticMessages(
+                            /*details*/ undefined,
+                            Diagnostics.Property_0_in_type_1_is_not_assignable_to_the_same_property_in_base_type_2,
+                            unescapeLeadingUnderscores(declaredProp.escapedName),
+                            typeToString(typeWithThis),
+                            typeToString(getTypeOfSymbol(baseProp))
+                        );
+                        if (!checkTypeAssignableTo(getTypeOfSymbol(prop), getTypeOfSymbol(baseProp), member.name || member, /*message*/ undefined, rootChain)) {
+                            issuedMemberError = true;
+                        }
+                    }
+                }
+            }
+            if (!issuedMemberError) {
+                // check again with diagnostics to generate a less-specific error
+                checkTypeAssignableTo(typeWithThis, baseWithThis, node.name || node, broadDiag);
+            }
+        }
+
         function checkBaseTypeAccessibility(type: Type, node: ExpressionWithTypeArguments) {
             const signatures = getSignaturesOfType(type, SignatureKind.Construct);
             if (signatures.length) {

src/compiler/diagnosticMessages.json

@@ -1404,6 +1404,10 @@
         "category": "Error",
         "code": 2415
     },
+    "Property '{0}' in type '{1}' is not assignable to the same property in base type '{2}'.": {
+        "category": "Error",
+        "code": 2416
+    },
     "Class static side '{0}' incorrectly extends base class static side '{1}'.": {
         "category": "Error",
         "code": 2417

tests/baselines/reference/abstractPropertyNegative.errors.txt

@@ -7,15 +7,12 @@ tests/cases/compiler/abstractPropertyNegative.ts(13,7): error TS2515: Non-abstra
 tests/cases/compiler/abstractPropertyNegative.ts(15,5): error TS1244: Abstract methods can only appear within an abstract class.
 tests/cases/compiler/abstractPropertyNegative.ts(16,37): error TS1005: '{' expected.
 tests/cases/compiler/abstractPropertyNegative.ts(19,3): error TS2540: Cannot assign to 'ro' because it is a constant or a read-only property.
-tests/cases/compiler/abstractPropertyNegative.ts(24,7): error TS2415: Class 'WrongTypePropertyImpl' incorrectly extends base class 'WrongTypeProperty'.
-  Types of property 'num' are incompatible.
-    Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/abstractPropertyNegative.ts(30,7): error TS2415: Class 'WrongTypeAccessorImpl' incorrectly extends base class 'WrongTypeAccessor'.
-  Types of property 'num' are incompatible.
-    Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/abstractPropertyNegative.ts(33,7): error TS2415: Class 'WrongTypeAccessorImpl2' incorrectly extends base class 'WrongTypeAccessor'.
-  Types of property 'num' are incompatible.
-    Type 'string' is not assignable to type 'number'.
+tests/cases/compiler/abstractPropertyNegative.ts(25,5): error TS2416: Property 'num' in type 'WrongTypePropertyImpl' is not assignable to the same property in base type 'number'.
+  Type 'string' is not assignable to type 'number'.
+tests/cases/compiler/abstractPropertyNegative.ts(31,9): error TS2416: Property 'num' in type 'WrongTypeAccessorImpl' is not assignable to the same property in base type 'number'.
+  Type 'string' is not assignable to type 'number'.
+tests/cases/compiler/abstractPropertyNegative.ts(34,5): error TS2416: Property 'num' in type 'WrongTypeAccessorImpl2' is not assignable to the same property in base type 'number'.
+  Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/abstractPropertyNegative.ts(38,18): error TS2676: Accessors must both be abstract or non-abstract.
 tests/cases/compiler/abstractPropertyNegative.ts(39,9): error TS2676: Accessors must both be abstract or non-abstract.
 tests/cases/compiler/abstractPropertyNegative.ts(40,9): error TS2676: Accessors must both be abstract or non-abstract.
@@ -65,28 +62,25 @@ tests/cases/compiler/abstractPropertyNegative.ts(41,18): error TS2676: Accessors
         abstract num: number;
     }
     class WrongTypePropertyImpl extends WrongTypeProperty {
-          ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2415: Class 'WrongTypePropertyImpl' incorrectly extends base class 'WrongTypeProperty'.
-!!! error TS2415:   Types of property 'num' are incompatible.
-!!! error TS2415:     Type 'string' is not assignable to type 'number'.
         num = "nope, wrong";
+        ~~~
+!!! error TS2416: Property 'num' in type 'WrongTypePropertyImpl' is not assignable to the same property in base type 'number'.
+!!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
     abstract class WrongTypeAccessor {
         abstract get num(): number;
     }
     class WrongTypeAccessorImpl extends WrongTypeAccessor {
-          ~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2415: Class 'WrongTypeAccessorImpl' incorrectly extends base class 'WrongTypeAccessor'.
-!!! error TS2415:   Types of property 'num' are incompatible.
-!!! error TS2415:     Type 'string' is not assignable to type 'number'.
         get num() { return "nope, wrong"; }
+            ~~~
+!!! error TS2416: Property 'num' in type 'WrongTypeAccessorImpl' is not assignable to the same property in base type 'number'.
+!!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
     class WrongTypeAccessorImpl2 extends WrongTypeAccessor {
-          ~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2415: Class 'WrongTypeAccessorImpl2' incorrectly extends base class 'WrongTypeAccessor'.
-!!! error TS2415:   Types of property 'num' are incompatible.
-!!! error TS2415:     Type 'string' is not assignable to type 'number'.
         num = "nope, wrong";
+        ~~~
+!!! error TS2416: Property 'num' in type 'WrongTypeAccessorImpl2' is not assignable to the same property in base type 'number'.
+!!! error TS2416:   Type 'string' is not assignable to type 'number'.
     }
 
     abstract class AbstractAccessorMismatch {

tests/baselines/reference/apparentTypeSubtyping.errors.txt

@@ -1,7 +1,6 @@
-tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtyping.ts(9,7): error TS2415: Class 'Derived<U>' incorrectly extends base class 'Base<string>'.
-  Types of property 'x' are incompatible.
-    Type 'String' is not assignable to type 'string'.
-      'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
+tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtyping.ts(10,5): error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+  Type 'String' is not assignable to type 'string'.
+    'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
 
 
 ==== tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtyping.ts (1 errors) ====
@@ -14,12 +13,11 @@ tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSubtypi
 
     // is String (S) a subtype of U extends String (T)? Would only be true if we used the apparent type of U (T)
     class Derived<U> extends Base<string> { // error
-          ~~~~~~~
-!!! error TS2415: Class 'Derived<U>' incorrectly extends base class 'Base<string>'.
-!!! error TS2415:   Types of property 'x' are incompatible.
-!!! error TS2415:     Type 'String' is not assignable to type 'string'.
-!!! error TS2415:       'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
         x: String;
+        ~
+!!! error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+!!! error TS2416:   Type 'String' is not assignable to type 'string'.
+!!! error TS2416:     'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
     }
 
     class Base2 {

tests/baselines/reference/apparentTypeSupertype.errors.txt

@@ -1,8 +1,7 @@
-tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSupertype.ts(9,7): error TS2415: Class 'Derived<U>' incorrectly extends base class 'Base'.
-  Types of property 'x' are incompatible.
-    Type 'U' is not assignable to type 'string'.
-      Type 'String' is not assignable to type 'string'.
-        'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
+tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSupertype.ts(10,5): error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+  Type 'U' is not assignable to type 'string'.
+    Type 'String' is not assignable to type 'string'.
+      'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
 
 
 ==== tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSupertype.ts (1 errors) ====
@@ -15,11 +14,10 @@ tests/cases/conformance/types/typeRelationships/apparentType/apparentTypeSuperty
 
     // is String (S) a subtype of U extends String (T)? Would only be true if we used the apparent type of U (T)
     class Derived<U extends String> extends Base { // error
-          ~~~~~~~
-!!! error TS2415: Class 'Derived<U>' incorrectly extends base class 'Base'.
-!!! error TS2415:   Types of property 'x' are incompatible.
-!!! error TS2415:     Type 'U' is not assignable to type 'string'.
-!!! error TS2415:       Type 'String' is not assignable to type 'string'.
-!!! error TS2415:         'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
         x: U;
+        ~
+!!! error TS2416: Property 'x' in type 'Derived<U>' is not assignable to the same property in base type 'string'.
+!!! error TS2416:   Type 'U' is not assignable to type 'string'.
+!!! error TS2416:     Type 'String' is not assignable to type 'string'.
+!!! error TS2416:       'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.
     }