Condier keysof types string like, dont get index types

Author: weswigham

src/compiler/checker.ts

@@ -5151,21 +5151,11 @@ namespace ts {
         }
 
         function resolveKeysQueryType(type: KeysQueryType): Type {
-            // Get index types to include in the union if need be
-            let indexTypes: Type[];
-            const numberIndex = getIndexInfoOfType(type.baseType, IndexKind.Number);
-            const stringIndex = getIndexInfoOfType(type.baseType, IndexKind.String);
-            if (numberIndex) {
-                indexTypes = [numberType];
-            }
-            if (stringIndex) {
-                indexTypes ? indexTypes.push(stringType) : indexTypes = [stringType];
-            }
             // Skip any essymbol members and remember to unescape the identifier before making a type from it
-            const memberTypes = concatenate(indexTypes, map(filter(getPropertiesOfType(type.baseType),
+            const memberTypes = map(filter(getPropertiesOfType(type.baseType),
                 symbol => !startsWith(symbol.name, "__@")),
                 symbol => getLiteralTypeForText(TypeFlags.StringLiteral, unescapeIdentifier(symbol.name))
-            ));
+            );
             return memberTypes ? getUnionType(memberTypes) : neverType;
         }
 
@@ -13404,7 +13394,7 @@ namespace ts {
                     contextualType = apparentType;
                 }
                 if (contextualType.flags & TypeFlags.KeysQuery) {
-                    return true;
+                    return type === stringType;
                 }
                 if (type.flags & TypeFlags.String) {
                     return maybeTypeOfKind(contextualType, TypeFlags.StringLiteral);

src/compiler/types.ts

@@ -2292,7 +2292,7 @@ namespace ts {
         Intrinsic = Any | String | Number | Boolean | BooleanLiteral | ESSymbol | Void | Undefined | Null | Never,
         /* @internal */
         Primitive = String | Number | Boolean | Enum | ESSymbol | Void | Undefined | Null | Literal,
-        StringLike = String | StringLiteral,
+        StringLike = String | StringLiteral | KeysQuery,
         NumberLike = Number | NumberLiteral | Enum | EnumLiteral,
         BooleanLike = Boolean | BooleanLiteral,
         EnumLike = Enum | EnumLiteral,

tests/cases/conformance/types/keysof/simpleKeysofTest.ts

@@ -16,9 +16,10 @@ function disambiguate2(): keysof ({a}) {return "a";}
 interface FooBar {
     foo: "yes";
     bar: "no";
+    [index: string]: string; // Remove when the indexer is patched to passthru unions
 }
 
-function pick(thing: FooBar, member: keysof FooBar): typeof member {
+function pick(thing: FooBar, member: keysof FooBar) {
     return thing[member];
 }
 
@@ -32,10 +33,12 @@ const x = pick2({a: "", b: 0}, realA);
 const xx = pick2({a: "", b: 0}, "a");
 const item = {0: "yes", 1: "no"};
 const xxx = pick2(item, "0");
-const xxxx = pick2(item, 0);
-item["0"].charCodeAt(0);
-item[0].charCodeAt(0);
 
-function pick3<U, T extends keysof U>(obj: U, key: T) {
-    key
-}
+function annotate<U, T extends keysof U>(obj: U, key: T): U & {annotation: T} {
+    const ret = obj as U & {annotation: T};
+    if (key === "annotation") return ret; // Already annotated
+    ret.annotation = key;
+    return ret;
+}
+
+annotate({a: "things", b: "stuff"}, "b").annotation === "b";