findAllReferences: Given a synthetic property, find references for the original property.

Author: Andy Hanson

src/services/findAllReferences.ts

@@ -273,7 +273,7 @@ namespace ts.FindAllReferences.Core {
             }
         }
 
-        const symbol = checker.getSymbolAtLocation(node);
+        let symbol = checker.getSymbolAtLocation(node);
 
         // Could not find a symbol e.g. unknown identifier
         if (!symbol) {
@@ -285,6 +285,9 @@ namespace ts.FindAllReferences.Core {
             return undefined;
         }
 
+        // If this property is derived from another one, find references on the original property instead.
+        symbol = (symbol as ts.SymbolLinks).syntheticOrigin || symbol;
+
         // The symbol was an internal symbol and does not have a declaration e.g. undefined symbol
         if (!symbol.declarations || !symbol.declarations.length) {
             return undefined;

tests/cases/fourslash/findAllRefsMappedType.ts

@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts'/>
+
+////interface T { [|{| "isWriteAccess": true, "isDefinition": true |}a|]: number; }
+////type U = { readonly [K in keyof T]?: string };
+////declare const t: T;
+////t.[|a|];
+////declare const u: U;
+////u.[|a|];
+
+verify.singleReferenceGroup("(property) T.a: number");