Merge pull request #16217 from CyrusNajmabadi/useCollectionIssue

Ensure the 'Add' name actually matches before accepting any invocation expression.
Fixes #16158

src/EditorFeatures/CSharpTest/UseCollectionInitializer/UseCollectionInitializerTests.cs

@@ -646,6 +646,43 @@ void M()
             }
         };
     }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseCollectionInitializer)]
+        [WorkItem(16158, "https://github.com/dotnet/roslyn/issues/16158")]
+        public async Task TestIncorrectAddName()
+        {
+            await TestAsync(
+@"using System.Collections.Generic;
+
+public class Foo
+{
+    public static void Bar()
+    {
+        string item = null;
+        var items = new List<string>();
+
+        var values = new [||]List<string>(); // Collection initialization can be simplified
+        values.Add(item);
+        values.AddRange(items);
+    }
+}",
+@"using System.Collections.Generic;
+
+public class Foo
+{
+    public static void Bar()
+    {
+        string item = null;
+        var items = new List<string>();
+
+        var values = new List<string>
+        {
+            item
+        }; // Collection initialization can be simplified
+        values.AddRange(items);
+    }
 }");
         }
     }

src/Features/Core/Portable/UseCollectionInitializer/ObjectCreationExpressionAnalyzer.cs

@@ -186,7 +186,7 @@ private void AddMatches(ArrayBuilder<TExpressionStatementSyntax> matches)
                 return false;
             }
 
-            _syntaxFacts.GetPartsOfMemberAccessExpression(memberAccess, out instance, out var memberName);
+            _syntaxFacts.GetPartsOfMemberAccessExpression(memberAccess, out var localInstance, out var memberName);
             _syntaxFacts.GetNameAndArityOfSimpleName(memberName, out var name, out var arity);
 
             if (arity != 0 || !name.Equals(nameof(IList.Add)))
@@ -194,6 +194,7 @@ private void AddMatches(ArrayBuilder<TExpressionStatementSyntax> matches)
                 return false;
             }
 
+            instance = localInstance;
             return true;
         }