Support GotoDefinition in LINQ query syntax (#23049)

* Initial support for GotoDefinition in LINQ query syntax.

* Fixed naming issues.

* Fixed failing tests.

* Added support for Cast<> in from clause. Removed support for degenerated select clause. Reverted changes causing regressions.

* Added support for tokens to distinguish which MethodSymbol to return for a SyntaxNode that binds to more than one method. This adds support for range variable types and orderby.

* Fixed regression. Suppressed quick-info for degenerated query expressions.

* Added quick info tests according to the proposal.

* Added test for GotoDefinition. Moved logic for degenerated clauses to deeper layer.

* Added GotoDefinition for let test.

* Added test for incomplete orderby clause

* Code refactorings (Review feedback).

* PR feedback (nits)

* PR feedback (code comments).

* Revert changes in compiler.

* Revert changes in compiler (2).

* Added test for single from clause with out cast.

* Removed call to GetLanguageService and ValueTuple.Create

* Unify to return default;

* Corrected ISyntaxFactsService.IsQueryKeyword for VB and C#

Author: MaStr11

src/EditorFeatures/CSharpTest/QuickInfo/SemanticQuickInfoSourceTests.cs

@@ -280,11 +280,10 @@ private async Task<ValueTuple<SemanticModel, ImmutableArray<ISymbol>>> BindToken
             SyntaxToken token,
             CancellationToken cancellationToken)
         {
+            var syntaxFacts = document.Project.LanguageServices.GetService<ISyntaxFactsService>();
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
             var enclosingType = semanticModel.GetEnclosingNamedType(token.SpanStart, cancellationToken);
 
-            var syntaxFacts = document.Project.LanguageServices.GetService<ISyntaxFactsService>();
-
             ImmutableArray<ISymbol> symbols;
             if (GetBindableNodeForTokenIndicatingLambda(token, out SyntaxNode lambdaSyntax))
             {
@@ -296,7 +295,7 @@ private async Task<ValueTuple<SemanticModel, ImmutableArray<ISymbol>>> BindToken
                     .GetSymbols(includeType: true);
             }
 
-            var bindableParent = document.GetLanguageService<ISyntaxFactsService>().GetBindableParent(token);
+            var bindableParent = syntaxFacts.GetBindableParent(token);
             var overloads = semanticModel.GetMemberGroup(bindableParent, cancellationToken);
 
             symbols = symbols.Where(IsOk)
@@ -307,12 +306,8 @@ private async Task<ValueTuple<SemanticModel, ImmutableArray<ISymbol>>> BindToken
 
             if (symbols.Any())
             {
-                var typeParameter = symbols.First() as ITypeParameterSymbol;
-                return ValueTuple.Create(
-                    semanticModel,
-                    typeParameter != null && typeParameter.TypeParameterKind == TypeParameterKind.Cref
-                        ? ImmutableArray<ISymbol>.Empty
-                        : symbols);
+                var discardSymbols = (symbols.First() as ITypeParameterSymbol)?.TypeParameterKind == TypeParameterKind.Cref;
+                return (semanticModel, discardSymbols ? ImmutableArray<ISymbol>.Empty : symbols);
             }
 
             // Couldn't bind the token to specific symbols.  If it's an operator, see if we can at
@@ -322,12 +317,11 @@ private async Task<ValueTuple<SemanticModel, ImmutableArray<ISymbol>>> BindToken
                 var typeInfo = semanticModel.GetTypeInfo(token.Parent, cancellationToken);
                 if (IsOk(typeInfo.Type))
                 {
-                    return ValueTuple.Create(semanticModel,
-                        ImmutableArray.Create<ISymbol>(typeInfo.Type));
+                    return (semanticModel, ImmutableArray.Create<ISymbol>(typeInfo.Type));
                 }
             }
 
-            return ValueTuple.Create(semanticModel, ImmutableArray<ISymbol>.Empty);
+            return (semanticModel, ImmutableArray<ISymbol>.Empty);
         }
 
         private static bool IsOk(ISymbol symbol)