Merge pull request #18663 from CyrusNajmabadi/wrongArityClassification

Classify type names, even when arity does not match.

src/EditorFeatures/CSharpTest/Classification/SemanticClassifierTests.cs

@@ -279,7 +279,7 @@ public async Task GenericClassNameButOtherArity()
 class C
 {
     A d;
-}");
+}", Class("A"));
         }
 
         [Fact, Trait(Traits.Feature, Traits.Features.Classification)]

src/EditorFeatures/CSharpTest/Classification/TotalClassifierTests.cs

@@ -788,9 +788,62 @@ public MyClass(int x)
                 Punctuation.CloseParen,
                 Punctuation.OpenCurly,
                 Punctuation.CloseCurly,
-                Punctuation.CloseCurly
+                Punctuation.CloseCurly);
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.Classification)]
+        public async Task TestGenericTypeWithNoArity()
+        {
+            await TestAsync(
+@"
+using System.Collections.Generic;
+
+class Program : IReadOnlyCollection
+{
+}",
+                Keyword("using"),
+                Identifier("System"),
+                Operators.Dot,
+                Identifier("Collections"),
+                Operators.Dot,
+                Identifier("Generic"),
+                Punctuation.Semicolon,
+                Keyword("class"),
+                Class("Program"),
+                Punctuation.Colon,
+                Interface("IReadOnlyCollection"),
+                Punctuation.OpenCurly,
+                Punctuation.CloseCurly);
+        }
 
-                );
+        [Fact, Trait(Traits.Feature, Traits.Features.Classification)]
+        public async Task TestGenericTypeWithWrongArity()
+        {
+            await TestAsync(
+@"
+using System.Collections.Generic;
+
+class Program : IReadOnlyCollection<int,string>
+{
+}",
+                Keyword("using"),
+                Identifier("System"),
+                Operators.Dot,
+                Identifier("Collections"),
+                Operators.Dot,
+                Identifier("Generic"),
+                Punctuation.Semicolon,
+                Keyword("class"),
+                Class("Program"),
+                Punctuation.Colon,
+                Identifier("IReadOnlyCollection"),
+                Punctuation.OpenAngle,
+                Keyword("int"),
+                Punctuation.Comma,
+                Keyword("string"),
+                Punctuation.CloseAngle,
+                Punctuation.OpenCurly,
+                Punctuation.CloseCurly);
         }
     }
-}
+}
\ No newline at end of file

src/Workspaces/CSharp/Portable/Classification/Classifiers/NameSyntaxClassifier.cs

@@ -221,6 +221,18 @@ private static ISymbol TryGetSymbol(NameSyntax name, SymbolInfo symbolInfo, Sema
                             return firstSymbol;
                         }
 
+                        break;
+
+                    case CandidateReason.WrongArity:
+                        if (name.GetRightmostName().Arity == 0)
+                        {
+                            // When the user writes something like "IList" we don't want to *not* classify 
+                            // just because the type bound to "IList<T>".  This is also important for use
+                            // cases like "Add-using" where it can be confusing when the using is added for
+                            // "using System.Collection.Generic" but then the type name still does not classify.
+                            return firstSymbol;
+                        }
+
                         break;
                 }
             }