Fix warning

src/Workspaces/CSharp/Portable/LanguageServices/CSharpTypeInferenceService.TypeInferrer.cs

@@ -720,7 +720,7 @@ private void DetermineTypeParameterMapping(ITypeSymbol inferredType, ITypeSymbol
                 }
 
                 var outerTypes = InferTypes(arrayCreationExpression);
-                return outerTypes.Where(o => o is IArrayTypeSymbol);
+                return outerTypes.Where(o => o.InferredType is IArrayTypeSymbol);
             }
 
             private IEnumerable<TypeInferenceInfo> InferTypeInArrayRankSpecifier(ArrayRankSpecifierSyntax arrayRankSpecifier, SyntaxToken? previousToken = null)