diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
index caaadc4583465..78b54a2b7481e 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
@@ -3133,12 +3133,12 @@ public void RefAssignment_Foreach()
 
             void verify(string variableType, string itemType, params DiagnosticDescription[] expected)
             {
-                var source = @"
+                var source = $$"""
 class C<T>
 {
     void M(RefEnumerable collection)
     {
-        foreach (ref VARTYPE item in collection)
+        foreach (ref {{variableType}} item in collection)
         {
             item.ToString();
         }
@@ -3149,13 +3149,14 @@ class RefEnumerable
         public StructEnum GetEnumerator() => throw null!;
         public struct StructEnum
         {
-            public ref ITEMTYPE Current => throw null!;
+            public ref {{itemType}} Current => throw null!;
             public bool MoveNext() => throw null!;
         }
     }
-}";
+}
+""";
 
-                var comp = CreateCompilation(source.Replace("VARTYPE", variableType).Replace("ITEMTYPE", itemType), options: WithNullableEnable());
+                var comp = CreateCompilation(source, options: WithNullableEnable());
                 comp.VerifyDiagnostics(expected);
             }
         }