error on duplicate symbols in classes

Author: Zzzen

src/compiler/checker.ts

@@ -12683,7 +12683,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 // or if we have another early-bound symbol declaration with the same name and
                 // conflicting flags.
                 const earlySymbol = earlySymbols && earlySymbols.get(memberName);
-                if (lateSymbol.flags & getExcludedSymbolFlags(symbolFlags) || earlySymbol) {
+                // Duplicate property declarations of classes are checked in checkClassForDuplicateDeclarations.
+                if (!(parent.flags & SymbolFlags.Class) && (lateSymbol.flags & getExcludedSymbolFlags(symbolFlags) || earlySymbol)) {
                     // If we have an existing early-bound member, combine its declarations so that we can
                     // report an error at each declaration.
                     const declarations = earlySymbol ? concatenate(earlySymbol.declarations, lateSymbol.declarations) : lateSymbol.declarations;
@@ -38878,7 +38879,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     isStaticMember ? staticNames :
                     instanceNames;
 
-                const memberName = name && getPropertyNameForPropertyNameNode(name);
+                const memberName = name && getEffectivePropertyNameForPropertyNameNode(name);
                 if (memberName) {
                     switch (member.kind) {
                         case SyntaxKind.GetAccessor:
@@ -38947,7 +38948,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             const memberNameNode = member.name;
             const isStaticMember = isStatic(member);
             if (isStaticMember && memberNameNode) {
-                const memberName = getPropertyNameForPropertyNameNode(memberNameNode);
+                const memberName = getEffectivePropertyNameForPropertyNameNode(memberNameNode);
                 switch (memberName) {
                     case "name":
                     case "length":

tests/baselines/reference/mappedTypeProperties.errors.txt

@@ -6,15 +6,19 @@ mappedTypeProperties.ts(23,5): error TS7061: A mapped type may not declare prope
 mappedTypeProperties.ts(27,5): error TS7061: A mapped type may not declare properties or methods.
 mappedTypeProperties.ts(31,5): error TS7061: A mapped type may not declare properties or methods.
 mappedTypeProperties.ts(34,5): error TS7061: A mapped type may not declare properties or methods.
+mappedTypeProperties.ts(34,6): error TS2304: Cannot find name 'P'.
+mappedTypeProperties.ts(34,11): error TS2693: 'PlaceType' only refers to a type, but is being used as a value here.
 mappedTypeProperties.ts(37,5): error TS7061: A mapped type may not declare properties or methods.
+mappedTypeProperties.ts(37,6): error TS2304: Cannot find name 'P'.
+mappedTypeProperties.ts(37,11): error TS2693: 'PlaceType' only refers to a type, but is being used as a value here.
 mappedTypeProperties.ts(40,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 mappedTypeProperties.ts(40,6): error TS2304: Cannot find name 'P'.
 mappedTypeProperties.ts(40,6): error TS2362: The left-hand side of an arithmetic operation must be of type 'any', 'number', 'bigint' or an enum type.
 mappedTypeProperties.ts(40,11): error TS2322: Type 'string' is not assignable to type 'object'.
 mappedTypeProperties.ts(40,17): error TS2363: The right-hand side of an arithmetic operation must be of type 'any', 'number', 'bigint' or an enum type.
 
 
-==== mappedTypeProperties.ts (14 errors) ====
+==== mappedTypeProperties.ts (18 errors) ====
     export type PlaceType = 'openSky' | 'roofed' | 'garage'
     type Before = {
         model: 'hour' | 'day';
@@ -65,11 +69,19 @@ mappedTypeProperties.ts(40,17): error TS2363: The right-hand side of an arithmet
         [P in PlaceType]: any
         ~~~~~~~~~~~~~~~~
 !!! error TS7061: A mapped type may not declare properties or methods.
+         ~
+!!! error TS2304: Cannot find name 'P'.
+              ~~~~~~~~~
+!!! error TS2693: 'PlaceType' only refers to a type, but is being used as a value here.
     }
     const D = class {
         [P in PlaceType]: any
         ~~~~~~~~~~~~~~~~
 !!! error TS7061: A mapped type may not declare properties or methods.
+         ~
+!!! error TS2304: Cannot find name 'P'.
+              ~~~~~~~~~
+!!! error TS2693: 'PlaceType' only refers to a type, but is being used as a value here.
     }
     const E = class {
         [P in 'a' | 'b']: any