fix(57635): duplicate property name error when trying to overwrite early-bound prop with late-bound prop (#57717)

Author: idango10

src/compiler/checker.ts

@@ -13073,12 +13073,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 let lateSymbol = lateSymbols.get(memberName);
                 if (!lateSymbol) lateSymbols.set(memberName, lateSymbol = createSymbol(SymbolFlags.None, memberName, CheckFlags.Late));
 
-                // Report an error if a late-bound member has the same name as an early-bound member,
-                // or if we have another early-bound symbol declaration with the same name and
-                // conflicting flags.
+                // Report an error if there's a symbol declaration with the same name and conflicting flags.
                 const earlySymbol = earlySymbols && earlySymbols.get(memberName);
                 // Duplicate property declarations of classes are checked in checkClassForDuplicateDeclarations.
-                if (!(parent.flags & SymbolFlags.Class) && (lateSymbol.flags & getExcludedSymbolFlags(symbolFlags) || earlySymbol)) {
+                if (!(parent.flags & SymbolFlags.Class) && lateSymbol.flags & getExcludedSymbolFlags(symbolFlags)) {
                     // 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;

tests/baselines/reference/dynamicNamesErrors.errors.txt

@@ -1,5 +1,3 @@
-dynamicNamesErrors.ts(5,5): error TS2718: Duplicate property '1'.
-dynamicNamesErrors.ts(6,5): error TS2733: Property '1' was also declared here.
 dynamicNamesErrors.ts(19,5): error TS2717: Subsequent property declarations must have the same type.  Property '[c1]' must be of type 'number', but here has type 'string'.
 dynamicNamesErrors.ts(24,1): error TS2322: Type 'T2' is not assignable to type 'T1'.
   Types of property '[c0]' are incompatible.
@@ -9,17 +7,13 @@ dynamicNamesErrors.ts(25,1): error TS2322: Type 'T1' is not assignable to type '
     Type 'number' is not assignable to type 'string'.
 
 
-==== dynamicNamesErrors.ts (5 errors) ====
+==== dynamicNamesErrors.ts (3 errors) ====
     const c0 = "1";
     const c1 = 1;
 
     interface T0 {
         [c0]: number;
-        ~~~~
-!!! error TS2718: Duplicate property '1'.
         1: number;
-        ~
-!!! error TS2733: Property '1' was also declared here.
     }
 
     interface T1 {

tests/baselines/reference/dynamicNamesErrors.symbols

@@ -11,11 +11,11 @@ interface T0 {
 >T0 : Symbol(T0, Decl(dynamicNamesErrors.ts, 1, 13))
 
     [c0]: number;
->[c0] : Symbol(T0[c0], Decl(dynamicNamesErrors.ts, 3, 14))
+>[c0] : Symbol(T0[1], Decl(dynamicNamesErrors.ts, 4, 17), Decl(dynamicNamesErrors.ts, 3, 14))
 >c0 : Symbol(c0, Decl(dynamicNamesErrors.ts, 0, 5))
 
     1: number;
->1 : Symbol(T0[1], Decl(dynamicNamesErrors.ts, 4, 17))
+>1 : Symbol(T0[1], Decl(dynamicNamesErrors.ts, 4, 17), Decl(dynamicNamesErrors.ts, 3, 14))
 }
 
 interface T1 {

tests/cases/fourslash/allowLateBoundSymbolsOverwriteEarlyBoundSymbols.ts

@@ -0,0 +1,16 @@
+/// <reference path="fourslash.ts"/>
+
+//// export {};
+
+//// const prop = "abc";
+
+//// function foo(): void {};
+//// foo.abc = 10;
+//// foo[prop] = 10;
+
+//// interface T0 {
+////     [prop]: number;
+////     abc: number;
+//// }
+
+verify.noErrors();