Resolve upfront so recursive mapped types appear empty

ahejlsberg · ahejlsberg · commit c5ab4735ac01 · 2016-11-16T06:48:51.000-08:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -4489,6 +4489,8 @@ namespace ts {
             const members: SymbolTable = createMap<Symbol>();
             let stringIndexInfo: IndexInfo;
             let numberIndexInfo: IndexInfo;
+            // Resolve upfront such that recursive references see an empty object type.
+            setStructuredTypeMembers(type, emptySymbols, emptyArray, emptyArray, undefined, undefined);
             // In { [P in K]: T }, we refer to P as the type parameter type, K as the constraint type,
             // and T as the template type.
             const typeParameter = getTypeParameterFromMappedType(type);
