microsoft · mhegazy · Jan 9, 2018 · Jan 9, 2018
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -19474,10 +19474,11 @@ namespace ts {
                 const ok =
                     (node.parent.kind === SyntaxKind.PropertyAccessExpression && (<PropertyAccessExpression>node.parent).expression === node) ||
                     (node.parent.kind === SyntaxKind.ElementAccessExpression && (<ElementAccessExpression>node.parent).expression === node) ||
-                    ((node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.QualifiedName) && isInRightSideOfImportOrExportAssignment(<Identifier>node));
+                    ((node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.QualifiedName) && isInRightSideOfImportOrExportAssignment(<Identifier>node) ||
+                    (node.parent.kind === SyntaxKind.TypeQuery && (<TypeQueryNode>node.parent).exprName === node));
 
                 if (!ok) {
-                    error(node, Diagnostics.const_enums_can_only_be_used_in_property_or_index_access_expressions_or_the_right_hand_side_of_an_import_declaration_or_export_assignment);
+                    error(node, Diagnostics.const_enums_can_only_be_used_in_property_or_index_access_expressions_or_the_right_hand_side_of_an_import_declaration_or_export_assignment_or_type_query);
                 }
             }
             return type;

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
@@ -1620,7 +1620,7 @@
         "category": "Error",
         "code": 2474
     },
-    "'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.": {
+    "'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.": {
         "category": "Error",
         "code": 2475
     },

diff --git a/tests/baselines/reference/constEnum3.js b/tests/baselines/reference/constEnum3.js
@@ -0,0 +1,20 @@
+//// [constEnum3.ts]
+const enum TestType { foo, bar }
+type TestTypeStr = keyof typeof TestType;
+
+function f1(f: TestType) { }
+function f2(f: TestTypeStr) { }
+
+f1(TestType.foo)
+f1(TestType.bar)
+f2('foo')
+f2('bar')
+
+
+//// [constEnum3.js]
+function f1(f) { }
+function f2(f) { }
+f1(0 /* foo */);
+f1(1 /* bar */);
+f2('foo');
+f2('bar');
diff --git a/tests/baselines/reference/constEnum3.symbols b/tests/baselines/reference/constEnum3.symbols
@@ -0,0 +1,38 @@
+=== tests/cases/conformance/constEnums/constEnum3.ts ===
+const enum TestType { foo, bar }
+>TestType : Symbol(TestType, Decl(constEnum3.ts, 0, 0))
+>foo : Symbol(TestType.foo, Decl(constEnum3.ts, 0, 21))
+>bar : Symbol(TestType.bar, Decl(constEnum3.ts, 0, 26))
+
+type TestTypeStr = keyof typeof TestType;
+>TestTypeStr : Symbol(TestTypeStr, Decl(constEnum3.ts, 0, 32))
+>TestType : Symbol(TestType, Decl(constEnum3.ts, 0, 0))
+
+function f1(f: TestType) { }
+>f1 : Symbol(f1, Decl(constEnum3.ts, 1, 41))
+>f : Symbol(f, Decl(constEnum3.ts, 3, 12))
+>TestType : Symbol(TestType, Decl(constEnum3.ts, 0, 0))
+
+function f2(f: TestTypeStr) { }
+>f2 : Symbol(f2, Decl(constEnum3.ts, 3, 28))
+>f : Symbol(f, Decl(constEnum3.ts, 4, 12))
+>TestTypeStr : Symbol(TestTypeStr, Decl(constEnum3.ts, 0, 32))
+
+f1(TestType.foo)
+>f1 : Symbol(f1, Decl(constEnum3.ts, 1, 41))
+>TestType.foo : Symbol(TestType.foo, Decl(constEnum3.ts, 0, 21))
+>TestType : Symbol(TestType, Decl(constEnum3.ts, 0, 0))
+>foo : Symbol(TestType.foo, Decl(constEnum3.ts, 0, 21))
+
+f1(TestType.bar)
+>f1 : Symbol(f1, Decl(constEnum3.ts, 1, 41))
+>TestType.bar : Symbol(TestType.bar, Decl(constEnum3.ts, 0, 26))
+>TestType : Symbol(TestType, Decl(constEnum3.ts, 0, 0))
+>bar : Symbol(TestType.bar, Decl(constEnum3.ts, 0, 26))
+
+f2('foo')
+>f2 : Symbol(f2, Decl(constEnum3.ts, 3, 28))
+
+f2('bar')
+>f2 : Symbol(f2, Decl(constEnum3.ts, 3, 28))
+
diff --git a/tests/baselines/reference/constEnum3.types b/tests/baselines/reference/constEnum3.types
@@ -0,0 +1,44 @@
+=== tests/cases/conformance/constEnums/constEnum3.ts ===
+const enum TestType { foo, bar }
+>TestType : TestType
+>foo : TestType.foo
+>bar : TestType.bar
+
+type TestTypeStr = keyof typeof TestType;
+>TestTypeStr : "foo" | "bar"
+>TestType : typeof TestType
+
+function f1(f: TestType) { }
+>f1 : (f: TestType) => void
+>f : TestType
+>TestType : TestType
+
+function f2(f: TestTypeStr) { }
+>f2 : (f: "foo" | "bar") => void
+>f : "foo" | "bar"
+>TestTypeStr : "foo" | "bar"
+
+f1(TestType.foo)
+>f1(TestType.foo) : void
+>f1 : (f: TestType) => void
+>TestType.foo : TestType.foo
+>TestType : typeof TestType
+>foo : TestType.foo
+
+f1(TestType.bar)
+>f1(TestType.bar) : void
+>f1 : (f: TestType) => void
+>TestType.bar : TestType.bar
+>TestType : typeof TestType
+>bar : TestType.bar
+
+f2('foo')
+>f2('foo') : void
+>f2 : (f: "foo" | "bar") => void
+>'foo' : "foo"
+
+f2('bar')
+>f2('bar') : void
+>f2 : (f: "foo" | "bar") => void
+>'bar' : "bar"
+
diff --git a/tests/baselines/reference/constEnumErrors.errors.txt b/tests/baselines/reference/constEnumErrors.errors.txt
@@ -5,9 +5,9 @@ tests/cases/compiler/constEnumErrors.ts(14,9): error TS2474: In 'const' enum dec
 tests/cases/compiler/constEnumErrors.ts(15,10): error TS2474: In 'const' enum declarations member initializer must be constant expression.
 tests/cases/compiler/constEnumErrors.ts(22,13): error TS2476: A const enum member can only be accessed using a string literal.
 tests/cases/compiler/constEnumErrors.ts(24,13): error TS2476: A const enum member can only be accessed using a string literal.
-tests/cases/compiler/constEnumErrors.ts(26,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
-tests/cases/compiler/constEnumErrors.ts(27,10): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
-tests/cases/compiler/constEnumErrors.ts(32,5): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+tests/cases/compiler/constEnumErrors.ts(26,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
+tests/cases/compiler/constEnumErrors.ts(27,10): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
+tests/cases/compiler/constEnumErrors.ts(32,5): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
 tests/cases/compiler/constEnumErrors.ts(40,9): error TS2477: 'const' enum member initializer was evaluated to a non-finite value.
 tests/cases/compiler/constEnumErrors.ts(41,9): error TS2477: 'const' enum member initializer was evaluated to a non-finite value.
 tests/cases/compiler/constEnumErrors.ts(42,9): error TS2478: 'const' enum member initializer was evaluated to disallowed value 'NaN'.
@@ -55,17 +55,17 @@ tests/cases/compiler/constEnumErrors.ts(42,9): error TS2478: 'const' enum member
 
     var x = E2;
             ~~
-!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
     var y = [E2];
              ~~
-!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
 
     function foo(t: any): void {
     }
 
     foo(E2);
         ~~
-!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
 
     const enum NaNOrInfinity {
         A = 9007199254740992,

diff --git a/tests/baselines/reference/constEnumPropertyAccess2.errors.txt b/tests/baselines/reference/constEnumPropertyAccess2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(13,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(13,9): error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(14,12): error TS2476: A const enum member can only be accessed using a string literal.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(16,1): error TS2322: Type '"string"' is not assignable to type 'G'.
 tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(18,3): error TS2540: Cannot assign to 'B' because it is a constant or a read-only property.
@@ -19,7 +19,7 @@ tests/cases/conformance/constEnums/constEnumPropertyAccess2.ts(18,3): error TS25
     // Error from referring constant enum in any other context than a property access
     var z = G;
             ~
-!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment.
+!!! error TS2475: 'const' enums can only be used in property or index access expressions or the right hand side of an import declaration or export assignment or type query.
     var z1 = G[G.A];
                ~~~
 !!! error TS2476: A const enum member can only be accessed using a string literal.

diff --git a/tests/cases/conformance/constEnums/constEnum3.ts b/tests/cases/conformance/constEnums/constEnum3.ts
@@ -0,0 +1,10 @@
+const enum TestType { foo, bar }
+type TestTypeStr = keyof typeof TestType;
+
+function f1(f: TestType) { }
+function f2(f: TestTypeStr) { }
+
+f1(TestType.foo)
+f1(TestType.bar)
+f2('foo')
+f2('bar')