Merge pull request #12389 from Microsoft/keyofRelations

Minor fixes for 'keyof T' and indexed acces types

Author: ahejlsberg

src/compiler/checker.ts

@@ -6039,19 +6039,20 @@ namespace ts {
                 const id = objectType.id + "," + indexType.id;
                 return indexedAccessTypes[id] || (indexedAccessTypes[id] = createIndexedAccessType(objectType, indexType));
             }
-            const apparentType = getApparentType(objectType);
-            if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive)) {
+            const apparentObjectType = getApparentType(objectType);
+            const apparentIndexType = indexType.flags & TypeFlags.Index ? stringOrNumberType : indexType;
+            if (apparentIndexType.flags & TypeFlags.Union && !(apparentIndexType.flags & TypeFlags.Primitive)) {
                 const propTypes: Type[] = [];
-                for (const t of (<UnionType>indexType).types) {
-                    const propType = getPropertyTypeForIndexType(apparentType, t, accessNode, /*cacheSymbol*/ false);
+                for (const t of (<UnionType>apparentIndexType).types) {
+                    const propType = getPropertyTypeForIndexType(apparentObjectType, t, accessNode, /*cacheSymbol*/ false);
                     if (propType === unknownType) {
                         return unknownType;
                     }
                     propTypes.push(propType);
                 }
                 return getUnionType(propTypes);
             }
-            return getPropertyTypeForIndexType(apparentType, indexType, accessNode, /*cacheSymbol*/ true);
+            return getPropertyTypeForIndexType(apparentObjectType, apparentIndexType, accessNode, /*cacheSymbol*/ true);
         }
 
         function getTypeFromIndexedAccessTypeNode(node: IndexedAccessTypeNode) {
@@ -7125,7 +7126,10 @@ namespace ts {
 
                 if (source.flags & TypeFlags.Index) {
                     // A keyof T is related to a union type containing both string and number
-                    if (maybeTypeOfKind(target, TypeFlags.String) && maybeTypeOfKind(target, TypeFlags.Number)) {
+                    const related = relation === comparableRelation ?
+                        maybeTypeOfKind(target, TypeFlags.String | TypeFlags.Number) :
+                        maybeTypeOfKind(target, TypeFlags.String) && maybeTypeOfKind(target, TypeFlags.Number);
+                    if (related) {
                         return Ternary.True;
                     }
                 }
@@ -14256,7 +14260,7 @@ namespace ts {
             if (!isTypeAnyOrAllConstituentTypesHaveKind(leftType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol)) {
                 error(left, Diagnostics.The_left_hand_side_of_an_in_expression_must_be_of_type_any_string_number_or_symbol);
             }
-            if (!isTypeAnyOrAllConstituentTypesHaveKind(rightType, TypeFlags.Object | TypeFlags.TypeParameter)) {
+            if (!isTypeAnyOrAllConstituentTypesHaveKind(rightType, TypeFlags.Object | TypeFlags.TypeParameter | TypeFlags.IndexedAccess)) {
                 error(right, Diagnostics.The_right_hand_side_of_an_in_expression_must_be_of_type_any_an_object_type_or_a_type_parameter);
             }
             return booleanType;
@@ -17161,7 +17165,7 @@ namespace ts {
             const rightType = checkNonNullExpression(node.expression);
             // unknownType is returned i.e. if node.expression is identifier whose name cannot be resolved
             // in this case error about missing name is already reported - do not report extra one
-            if (!isTypeAnyOrAllConstituentTypesHaveKind(rightType, TypeFlags.Object | TypeFlags.TypeParameter)) {
+            if (!isTypeAnyOrAllConstituentTypesHaveKind(rightType, TypeFlags.Object | TypeFlags.TypeParameter | TypeFlags.IndexedAccess)) {
                 error(node.expression, Diagnostics.The_right_hand_side_of_a_for_in_statement_must_be_of_type_any_an_object_type_or_a_type_parameter);
             }
 

tests/baselines/reference/keyofAndIndexedAccess.js

@@ -181,6 +181,46 @@ function f40(c: C) {
     let z: Z = c["z"];
 }
 
+function f50<T>(k: keyof T, s: string, n: number) {
+    const x1 = s as keyof T;
+    const x2 = n as keyof T;
+    const x3 = k as string;
+    const x4 = k as number;
+    const x5 = k as string | number;
+}
+
+function f51<T, K extends keyof T>(k: K, s: string, n: number) {
+    const x1 = s as keyof T;
+    const x2 = n as keyof T;
+    const x3 = k as string;
+    const x4 = k as number;
+    const x5 = k as string | number;
+}
+
+function f52<T>(obj: { [x: string]: boolean }, k: keyof T, s: string, n: number) {
+    const x1 = obj[s];
+    const x2 = obj[n];
+    const x3 = obj[k];
+}
+
+function f53<T, K extends keyof T>(obj: { [x: string]: boolean }, k: K, s: string, n: number) {
+    const x1 = obj[s];
+    const x2 = obj[n];
+    const x3 = obj[k];
+}
+
+function f54<T>(obj: T, key: keyof T) {
+    for (let s in obj[key]) {
+    }
+    const b = "foo" in obj[key];
+}
+
+function f55<T, K extends keyof T>(obj: T, key: K) {
+    for (let s in obj[key]) {
+    }
+    const b = "foo" in obj[key];
+}
+
 // Repros from #12011
 
 class Base {
@@ -329,6 +369,40 @@ function f40(c) {
     var y = c["y"];
     var z = c["z"];
 }
+function f50(k, s, n) {
+    var x1 = s;
+    var x2 = n;
+    var x3 = k;
+    var x4 = k;
+    var x5 = k;
+}
+function f51(k, s, n) {
+    var x1 = s;
+    var x2 = n;
+    var x3 = k;
+    var x4 = k;
+    var x5 = k;
+}
+function f52(obj, k, s, n) {
+    var x1 = obj[s];
+    var x2 = obj[n];
+    var x3 = obj[k];
+}
+function f53(obj, k, s, n) {
+    var x1 = obj[s];
+    var x2 = obj[n];
+    var x3 = obj[k];
+}
+function f54(obj, key) {
+    for (var s in obj[key]) {
+    }
+    var b = "foo" in obj[key];
+}
+function f55(obj, key) {
+    for (var s in obj[key]) {
+    }
+    var b = "foo" in obj[key];
+}
 // Repros from #12011
 var Base = (function () {
     function Base() {
@@ -454,6 +528,16 @@ declare class C {
     private z;
 }
 declare function f40(c: C): void;
+declare function f50<T>(k: keyof T, s: string, n: number): void;
+declare function f51<T, K extends keyof T>(k: K, s: string, n: number): void;
+declare function f52<T>(obj: {
+    [x: string]: boolean;
+}, k: keyof T, s: string, n: number): void;
+declare function f53<T, K extends keyof T>(obj: {
+    [x: string]: boolean;
+}, k: K, s: string, n: number): void;
+declare function f54<T>(obj: T, key: keyof T): void;
+declare function f55<T, K extends keyof T>(obj: T, key: K): void;
 declare class Base {
     get<K extends keyof this>(prop: K): this[K];
     set<K extends keyof this>(prop: K, value: this[K]): void;