Merge pull request #44661 from Youssef1313/patch-2

Fix wrong reporting for removing parenthesis for stackalloc

src/Analyzers/CSharp/Tests/RemoveUnnecessaryParentheses/RemoveUnnecessaryExpressionParenthesesTests.cs

@@ -81,6 +81,20 @@ void M()
 }", new TestParameters(options: RequireArithmeticBinaryParenthesesForClarity));
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryParentheses)]
+        [WorkItem(44629, "https://github.com/dotnet/roslyn/issues/44629")]
+        public async Task TestStackAlloc()
+        {
+            await TestMissingAsync(
+@"class C
+{
+    void M()
+    {
+        var span = $$(stackalloc byte[8]);
+    }
+}");
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryParentheses)]
         public async Task TestArithmeticRequiredForClarity2()
         {

src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Extensions/ParenthesizedExpressionSyntaxExtensions.cs

@@ -57,6 +57,17 @@ public static bool CanRemoveParentheses(this ParenthesizedExpressionSyntax node,
                 return true;
             }
 
+            if (expression is StackAllocArrayCreationExpressionSyntax ||
+                expression is ImplicitStackAllocArrayCreationExpressionSyntax)
+            {
+                // var span = (stackalloc byte[8]);
+                // https://github.com/dotnet/roslyn/issues/44629
+                // The code semantics changes if the parenthesis removed.
+                // With parenthesis:    variable span is of type `Span<byte>`.
+                // Without parenthesis: variable span is of type `byte*` which can only be used in unsafe context.
+                return false;
+            }
+
             // (throw ...) -> throw ...
             if (expression.IsKind(SyntaxKind.ThrowExpression))
                 return true;