Transform 'keyof (A & B)' to 'keyof A | keyof B'

ahejlsberg · ahejlsberg · commit fe075f26a26a · 2018-03-02T09:11:33.000-08:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -7987,7 +7987,8 @@ namespace ts {
         }
 
         function getIndexType(type: Type): Type {
-            return maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive) ? getIndexTypeForGenericType(<InstantiableType | UnionOrIntersectionType>type) :
+            return type.flags & TypeFlags.Intersection ? getUnionType(map((<IntersectionType>type).types, t => getIndexType(t))) :
+                maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive) ? getIndexTypeForGenericType(<InstantiableType | UnionOrIntersectionType>type) :
                 getObjectFlags(type) & ObjectFlags.Mapped ? getConstraintTypeFromMappedType(<MappedType>type) :
                 type === wildcardType ? wildcardType :
                 type.flags & TypeFlags.Any || getIndexInfoOfType(type, IndexKind.String) ? stringType :

Original file line number	Diff line number	Diff line change
`@@ -7987,7 +7987,8 @@ namespace ts {`
`7987`	`7987`	`}`
`7988`	`7988`
`7989`	`7989`	`function getIndexType(type: Type): Type {`
`7990`		`- return maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive) ? getIndexTypeForGenericType(<InstantiableType \| UnionOrIntersectionType>type) :`
	`7990`	`+ return type.flags & TypeFlags.Intersection ? getUnionType(map((<IntersectionType>type).types, t => getIndexType(t))) :`
	`7991`	`+ maybeTypeOfKind(type, TypeFlags.InstantiableNonPrimitive) ? getIndexTypeForGenericType(<InstantiableType \| UnionOrIntersectionType>type) :`
`7991`	`7992`	`getObjectFlags(type) & ObjectFlags.Mapped ? getConstraintTypeFromMappedType(<MappedType>type) :`
`7992`	`7993`	`type === wildcardType ? wildcardType :`
`7993`	`7994`	`type.flags & TypeFlags.Any \|\| getIndexInfoOfType(type, IndexKind.String) ? stringType :`