diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts index b771a3b67be..849f503ef85 100644 --- a/src/compiler/binder.ts +++ b/src/compiler/binder.ts @@ -313,6 +313,11 @@ namespace ts { // declaration we have for this symbol, and then create a new symbol for this // declaration. // + // Note that when properties declared in Javascript constructors + // (marked by isReplaceableByMethod) conflict with another symbol, the property loses. + // Always. This allows the common Javascript pattern of overwriting a prototype method + // with an bound instance method of the same type: `this.method = this.method.bind(this)` + // // If we created a new symbol, either because we didn't have a symbol with this name // in the symbol table, or we conflicted with an existing symbol, then just add this // node as the sole declaration of the new symbol. @@ -329,7 +334,7 @@ namespace ts { } if (symbol.flags & excludes) { - if (symbol.isDiscardable) { + if (symbol.isReplaceableByMethod) { // Javascript constructor-declared symbols can be discarded in favor of // prototype symbols like methods. symbol = symbolTable[name] = createSymbol(SymbolFlags.None, name); @@ -1988,7 +1993,7 @@ namespace ts { // It's acceptable for multiple 'this' assignments of the same identifier to occur // AND it can be overwritten by subsequent method declarations const symbol = declareSymbol(assignee.symbol.members, assignee.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes & ~SymbolFlags.Property); - symbol.isDiscardable = true; + symbol.isReplaceableByMethod = true; } function bindPrototypePropertyAssignment(node: BinaryExpression) { diff --git a/src/compiler/types.ts b/src/compiler/types.ts index f5cee2f8f8f..70bd3c3c070 100644 --- a/src/compiler/types.ts +++ b/src/compiler/types.ts @@ -2137,7 +2137,7 @@ namespace ts { /* @internal */ exportSymbol?: Symbol; // Exported symbol associated with this symbol /* @internal */ constEnumOnlyModule?: boolean; // True if module contains only const enums or other modules with only const enums /* @internal */ isReferenced?: boolean; // True if the symbol is referenced elsewhere - /* @internal */ isDiscardable?: boolean; // True if a Javascript class property can be overwritten by a method + /* @internal */ isReplaceableByMethod?: boolean; // Can this Javascript class property be replaced by a method symbol? } /* @internal */