Add missing test for CallerArgumentExpression

Closes dotnet#52745.
333fred · Nov 16, 2021 · c89048e · c89048e
1 parent c7521c9
commit c89048e
Showing 1 changed file with 23 additions and 0 deletions.
diff --git a/src/Compilers/CSharp/Test/Emit/Attributes/AttributeTests_CallerInfoAttributes.cs b/src/Compilers/CSharp/Test/Emit/Attributes/AttributeTests_CallerInfoAttributes.cs
@@ -5752,5 +5752,28 @@ static void Main()
 ABC
 ");
         }
+
+        [Theory]
+        [InlineData("out")]
+        [InlineData("ref")]
+        [InlineData("in")]
+        public void CallerArgumentExpression_OnRefParameter(string refType)
+        {
+            var comp = CreateCompilation(@$"
+using System.Runtime.CompilerServices;
+#pragma warning disable CS8321
+
+void M(int i, [CallerArgumentExpression(""i"")] {refType} string s)
+{{
+    {(refType == "out" ? "s = null;" : "")}
+}}
+", targetFramework: TargetFramework.NetCoreApp);
+
+            comp.VerifyDiagnostics(
+                // (5,16): error CS8964: The CallerArgumentExpressionAttribute may only be applied to parameters with default values
+                // void M(int i, [CallerArgumentExpression("i")] ref string s)
+                Diagnostic(ErrorCode.ERR_BadCallerArgumentExpressionParamWithoutDefaultValue, "CallerArgumentExpression").WithLocation(5, 16)
+            );
+        }
     }
 }