Fix the quick info on error types

Author: sheetalkamat

src/compiler/checker.ts

@@ -1288,7 +1288,7 @@ module ts {
         }
 
         function writeTypeParameters(typeParameters: TypeParameter[], writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, typeStack?: Type[]) {
-            if (typeParameters) {
+            if (typeParameters && typeParameters.length) {
                 writePunctuation(writer, SyntaxKind.LessThanToken);
                 for (var i = 0; i < typeParameters.length; i++) {
                     if (i > 0) {

tests/baselines/reference/dontShowCompilerGeneratedMembers.errors.txt

@@ -2,14 +2,14 @@ tests/cases/compiler/dontShowCompilerGeneratedMembers.ts(3,5): error TS1098: Typ
 tests/cases/compiler/dontShowCompilerGeneratedMembers.ts(3,6): error TS1005: '(' expected.
 tests/cases/compiler/dontShowCompilerGeneratedMembers.ts(3,6): error TS1139: Type parameter declaration expected.
 tests/cases/compiler/dontShowCompilerGeneratedMembers.ts(4,1): error TS1109: Expression expected.
-tests/cases/compiler/dontShowCompilerGeneratedMembers.ts(1,5): error TS2322: Type 'number' is not assignable to type '{ <>(): any; x: number; }':
+tests/cases/compiler/dontShowCompilerGeneratedMembers.ts(1,5): error TS2322: Type 'number' is not assignable to type '{ (): any; x: number; }':
   Property 'x' is missing in type 'Number'.
 
 
 ==== tests/cases/compiler/dontShowCompilerGeneratedMembers.ts (5 errors) ====
     var f: {
         ~
-!!! error TS2322: Type 'number' is not assignable to type '{ <>(): any; x: number; }':
+!!! error TS2322: Type 'number' is not assignable to type '{ (): any; x: number; }':
 !!! error TS2322:   Property 'x' is missing in type 'Number'.
         x: number;
         <-

tests/cases/fourslash_old/quickInfoOnErrorTypes1.ts renamed to tests/cases/fourslash/quickInfoOnErrorTypes1.ts

@@ -6,4 +6,4 @@
 ////};
 
 goTo.marker('A');
-verify.quickInfoIs('{ x: number; (): any; }', "", "f", "var");
+verify.quickInfoIs('(var) f: {\n    (): any;\n    x: number;\n}', "");