don't sort exception types before display

src/EditorFeatures/CSharpTest/QuickInfo/SemanticQuickInfoSourceTests.cs

@@ -4152,7 +4152,8 @@ class TestClass
         /// <exception cref=""T:MyNs.MyException2""></exception>
         /// <exception cref=""System.Int32""></exception>
         /// <exception cref=""double""></exception>
-        /// <exception cref=""Not_A_Class_And_Therefore_Not_Listed""></exception>
+        /// <exception cref=""Not_A_Class_But_Still_Displayed""></exception>
+        /// <exception cref=""T:"">looks like a proper prefix but isn't</exception>
         void M()
         {
             M$$();
@@ -4160,7 +4161,7 @@ void M()
     }
 }
 ",
-                Exceptions($"\r\n{WorkspacesResources.Exceptions}\r\n  MyException1\r\n  MyException2\r\n  double\r\n  int"));
+                Exceptions($"\r\n{WorkspacesResources.Exceptions}\r\n  MyException1\r\n  MyException2\r\n  int\r\n  double\r\n  Not_A_Class_But_Still_Displayed\r\n  T:"));
         }
     }
 }

src/EditorFeatures/VisualBasicTest/QuickInfo/SemanticQuickInfoSourceTests.vb

@@ -2049,14 +2049,15 @@ Namespace MyNs
         ''' <exception cref=""T:MyNs.MyException2""></exception>
         ''' <exception cref=""System.Int32""></exception>
         ''' <exception cref=""Double""></exception>
-        ''' <exception cref=""Not_A_Class_And_Therefore_Not_Listed""></exception>
+        ''' <exception cref=""Not_A_Class_But_Still_Displayed""></exception>
+        ''' <exception cref=""T:"">looks like a proper prefix but isn't</exception>
         Sub M()
             M$$()
         End Sub
     End Class
 End Namespace
 ",
-                Exceptions($"{vbCrLf}{WorkspacesResources.Exceptions}{vbCrLf}  MyException1{vbCrLf}  MyException2{vbCrLf}  Double{vbCrLf}  Integer"))
+                Exceptions($"{vbCrLf}{WorkspacesResources.Exceptions}{vbCrLf}  MyException1{vbCrLf}  MyException2{vbCrLf}  Integer{vbCrLf}  Double{vbCrLf}  Not_A_Class_But_Still_Displayed{vbCrLf}  T:"))
         End Sub
 
     End Class

src/Features/Core/Portable/LanguageServices/SymbolDisplayService/AbstractSymbolDisplayService.AbstractSymbolDescriptionBuilder.cs

@@ -156,24 +156,32 @@ private async Task AddPartsAsync(ImmutableArray<ISymbol> symbols)
 
             private void AddExceptions(ISymbol symbol)
             {
-                // clean up the list of possible exceptions by de-duplicating and ordering them
-                var exceptions =
-                    symbol.GetDocumentationComment().ExceptionTypes
-                    .Distinct()
-                    .OrderBy(e => e)
-                    .Select(e => DocumentationCommentId.GetFirstSymbolForDeclarationId(e, _semanticModel.Compilation))
-                    .WhereNotNull()
-                    .ToList();
-                if (exceptions.Any())
+                var exceptionTypes = symbol.GetDocumentationComment().ExceptionTypes;
+                if (exceptionTypes.Any())
                 {
                     var parts = new List<SymbolDisplayPart>();
-                    parts.Add(new SymbolDisplayPart(SymbolDisplayPartKind.Text, null, $"\r\n{WorkspacesResources.Exceptions}"));
-
-                    foreach (var exception in exceptions)
+                    parts.Add(new SymbolDisplayPart(kind: SymbolDisplayPartKind.Text, symbol: null, text: $"\r\n{WorkspacesResources.Exceptions}"));
+                    foreach (var exceptionString in exceptionTypes)
                     {
                         parts.AddRange(LineBreak());
                         parts.AddRange(Space(count: 2));
-                        parts.AddRange(_displayService.ToMinimalDisplayParts(_semanticModel, _position, exception));
+
+                        // try to get the actual exception symbol
+                        var exceptionSymbol = DocumentationCommentId.GetFirstSymbolForDeclarationId(exceptionString, _semanticModel.Compilation);
+                        if (exceptionSymbol != null)
+                        {
+                            parts.AddRange(_displayService.ToMinimalDisplayParts(_semanticModel, _position, exceptionSymbol));
+                        }
+                        else
+                        {
+                            // unable to parse exception symbol, fall back to displaying the raw text after trying to
+                            // strip off the leading prefix of "[E|F|M|N|P|T|!]:"
+                            var colonIndex = exceptionString.IndexOf(':');
+                            var displayText = colonIndex >= 0 && exceptionString.Length > colonIndex + 1
+                                ? exceptionString.Substring(colonIndex + 1)
+                                : exceptionString;
+                            parts.Add(new SymbolDisplayPart(kind: SymbolDisplayPartKind.Text, symbol: null, text: displayText));
+                        }
                     }
 
                     AddToGroup(SymbolDescriptionGroups.Exceptions, parts);