Code review

Author: jbondc

src/compiler/checker.ts

@@ -6315,7 +6315,7 @@ module ts {
             if (allConstituentTypesHaveKind(indexType, TypeFlags.Any | TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbol)) {
 
                 // Try to use a number indexer.
-                if (allConstituentTypesHaveKind(indexType, TypeFlags.Any | TypeFlags.NumberLike )) {
+                if (allConstituentTypesHaveKind(indexType, TypeFlags.Any | TypeFlags.NumberLike)) {
                     let numberIndexType = getIndexTypeOfType(objectType, IndexKind.Number);
                     if (numberIndexType) {
                         return numberIndexType;
@@ -12100,6 +12100,20 @@ module ts {
             return false;
         }
 
+        function isValidTypeOfIndexSignatureParameter(parameter: ParameterDeclaration): boolean {
+            if (parameter.type.kind === SyntaxKind.StringKeyword || parameter.type.kind === SyntaxKind.NumberKeyword) {
+                return true;
+            }
+
+            if (parameter.type.kind === SyntaxKind.TypeReference) {
+                var type = getTypeFromTypeReference(<TypeReferenceNode>(parameter.type));
+                if (type.flags & TypeFlags.NumberLike) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         function checkGrammarIndexSignatureParameters(node: SignatureDeclaration): boolean {
             let parameter = node.parameters[0];
             if (node.parameters.length !== 1) {
@@ -12125,14 +12139,8 @@ module ts {
             if (!parameter.type) {
                 return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_must_have_a_type_annotation);
             }
-            if (parameter.type.kind === SyntaxKind.TypeReference) {
-                var type = getTypeFromTypeReference(<TypeReferenceNode>(parameter.type));
-                if (!(type.flags & TypeFlags.NumberLike)) {
-                    return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_type_must_be_string_number_or_Enum);
-                }
-
-            } else if (parameter.type.kind !== SyntaxKind.StringKeyword && parameter.type.kind !== SyntaxKind.NumberKeyword) {
-                return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_type_must_be_string_number_or_Enum);
+            if (!isValidTypeOfIndexSignatureParameter(parameter)) {
+                return grammarErrorOnNode(parameter.name, Diagnostics.An_index_signature_parameter_type_must_be_string_number_or_an_enum_type);
             }
             if (!node.type) {
                 return grammarErrorOnNode(node, Diagnostics.An_index_signature_must_have_a_type_annotation);

src/compiler/diagnosticInformationMap.generated.ts

@@ -18,7 +18,7 @@ module ts {
         An_index_signature_parameter_cannot_have_an_initializer: { code: 1020, category: DiagnosticCategory.Error, key: "An index signature parameter cannot have an initializer." },
         An_index_signature_must_have_a_type_annotation: { code: 1021, category: DiagnosticCategory.Error, key: "An index signature must have a type annotation." },
         An_index_signature_parameter_must_have_a_type_annotation: { code: 1022, category: DiagnosticCategory.Error, key: "An index signature parameter must have a type annotation." },
-        An_index_signature_parameter_type_must_be_string_number_or_Enum: { code: 1023, category: DiagnosticCategory.Error, key: "An index signature parameter type must be 'string', 'number' or Enum." },
+        An_index_signature_parameter_type_must_be_string_number_or_an_enum_type: { code: 1023, category: DiagnosticCategory.Error, key: "An index signature parameter type must be 'string', 'number', or an enum type." },
         A_class_or_interface_declaration_can_only_have_one_extends_clause: { code: 1024, category: DiagnosticCategory.Error, key: "A class or interface declaration can only have one 'extends' clause." },
         An_extends_clause_must_precede_an_implements_clause: { code: 1025, category: DiagnosticCategory.Error, key: "An 'extends' clause must precede an 'implements' clause." },
         A_class_can_only_extend_a_single_class: { code: 1026, category: DiagnosticCategory.Error, key: "A class can only extend a single class." },

src/compiler/diagnosticMessages.json

@@ -63,7 +63,7 @@
         "category": "Error",
         "code": 1022
     },
-    "An index signature parameter type must be 'string', 'number' or Enum.": {
+    "An index signature parameter type must be 'string', 'number', or an enum type.": {
         "category": "Error",
         "code": 1023
     },