Disallow type annotation on a for-of variable

src/compiler/checker.ts

@@ -8467,9 +8467,6 @@ module ts {
                 if (variableDeclarationList.declarations.length >= 1) {
                     var decl = variableDeclarationList.declarations[0];
                     checkVariableDeclaration(decl);
-                    if (decl.type) {
-                        error(decl, Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_use_a_type_annotation);
-                    }
                 }
             }
             else {
@@ -10769,11 +10766,18 @@ module ts {
                             Diagnostics.Only_a_single_variable_declaration_is_allowed_in_a_for_of_statement;
                         return grammarErrorOnFirstToken(variableList.declarations[1], diagnostic);
                     }
-                    if (variableList.declarations[0].initializer) {
+                    var firstDeclaration = variableList.declarations[0];
+                    if (firstDeclaration.initializer) {
                         var diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement ?
                             Diagnostics.The_variable_declaration_of_a_for_in_statement_cannot_have_an_initializer :
                             Diagnostics.The_variable_declaration_of_a_for_of_statement_cannot_have_an_initializer;
-                        return grammarErrorOnNode(variableList.declarations[0].name, diagnostic);
+                        return grammarErrorOnNode(firstDeclaration.name, diagnostic);
+                    }
+                    if (firstDeclaration.type) {
+                        var diagnostic = forInOrOfStatement.kind === SyntaxKind.ForInStatement ?
+                            Diagnostics.The_left_hand_side_of_a_for_in_statement_cannot_use_a_type_annotation :
+                            Diagnostics.The_left_hand_side_of_a_for_of_statement_cannot_use_a_type_annotation;
+                        return grammarErrorOnNode(firstDeclaration, diagnostic);
                     }
                 }
             }

src/compiler/diagnosticInformationMap.generated.ts

@@ -317,6 +317,7 @@ module ts {
         let_is_not_allowed_to_be_used_as_a_name_in_let_or_const_declarations: { code: 2476, category: DiagnosticCategory.Error, key: "'let' is not allowed to be used as a name in 'let' or 'const' declarations." },
         Cannot_initialize_outer_scoped_variable_0_in_the_same_scope_as_block_scoped_declaration_1: { code: 2477, category: DiagnosticCategory.Error, key: "Cannot initialize outer scoped variable '{0}' in the same scope as block scoped declaration '{1}'." },
         For_of_statements_are_only_available_when_targeting_ECMAScript_6_or_higher: { code: 2482, category: DiagnosticCategory.Error, key: "For-of statements are only available when targeting ECMAScript 6 or higher" },
+        The_left_hand_side_of_a_for_of_statement_cannot_use_a_type_annotation: { code: 2483, category: DiagnosticCategory.Error, key: "The left-hand side of a 'for...of' statement cannot use a type annotation." },
         Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },

src/compiler/diagnosticMessages.json

@@ -1260,6 +1260,10 @@
         "category": "Error",
         "code": 2482
     },
+    "The left-hand side of a 'for...of' statement cannot use a type annotation.": {
+        "category": "Error",
+        "code": 2483
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

tests/baselines/reference/parserES5ForOfStatement5.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/conformance/parser/ecmascript5/Statements/parserES5ForOfStatement5.ts(1,1): error TS2482: For-of statements are only available when targeting ECMAScript 6 or higher
+tests/cases/conformance/parser/ecmascript5/Statements/parserES5ForOfStatement5.ts(1,10): error TS2483: The left-hand side of a 'for...of' statement cannot use a type annotation.
 
 
 ==== tests/cases/conformance/parser/ecmascript5/Statements/parserES5ForOfStatement5.ts (1 errors) ====
     for (var a: number of X) {
-    ~~~
-!!! error TS2482: For-of statements are only available when targeting ECMAScript 6 or higher
+             ~
+!!! error TS2483: The left-hand side of a 'for...of' statement cannot use a type annotation.
     }

tests/baselines/reference/parserForInStatement7.errors.txt

@@ -1,12 +1,9 @@
-tests/cases/conformance/parser/ecmascript5/Statements/parserForInStatement7.ts(1,10): error TS2404: The left-hand side of a 'for...in' statement cannot use a type annotation.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForInStatement7.ts(1,25): error TS1091: Only a single variable declaration is allowed in a 'for...in' statement.
 tests/cases/conformance/parser/ecmascript5/Statements/parserForInStatement7.ts(1,43): error TS2304: Cannot find name 'X'.
 
 
-==== tests/cases/conformance/parser/ecmascript5/Statements/parserForInStatement7.ts (3 errors) ====
+==== tests/cases/conformance/parser/ecmascript5/Statements/parserForInStatement7.ts (2 errors) ====
     for (var a: number = 1, b: string = "" in X) {
-             ~
-!!! error TS2404: The left-hand side of a 'for...in' statement cannot use a type annotation.
                             ~
 !!! error TS1091: Only a single variable declaration is allowed in a 'for...in' statement.
                                               ~

tests/baselines/reference/parserForOfStatement5.errors.txt

@@ -0,0 +1,8 @@
+tests/cases/conformance/parser/ecmascript6/Iterators/parserForOfStatement5.ts(1,10): error TS2483: The left-hand side of a 'for...of' statement cannot use a type annotation.
+
+
+==== tests/cases/conformance/parser/ecmascript6/Iterators/parserForOfStatement5.ts (1 errors) ====
+    for (var a: number of X) {
+             ~
+!!! error TS2483: The left-hand side of a 'for...of' statement cannot use a type annotation.
+    }