Add comment in parser and use raw string literals in tests

Copilot · CyrusNajmabadi · Copilot · commit 025f321e3bf3 · 2025-10-24T14:42:37.000Z
Co-authored-by: CyrusNajmabadi &lt;4564579+CyrusNajmabadi@users.noreply.github.com&gt;
diff --git a/src/Compilers/CSharp/Portable/Parser/LanguageParser.cs b/src/Compilers/CSharp/Portable/Parser/LanguageParser.cs
@@ -10513,6 +10513,9 @@ private void ParseDeclarationModifiers(SyntaxListBuilder list, bool isUsingDecla
                 {
                     mod = this.AddError(mod, ErrorCode.ERR_BadMemberFlag, mod.Text);
                 }
+                // Note: Duplicate modifiers are not reported here during parsing.
+                // They will be reported during binding (see Binder_Statements.BindDeclarationStatementParts
+                // and ModifierUtils.ToDeclarationModifiers).
 
                 list.Add(mod);
             }
diff --git a/src/Compilers/CSharp/Test/Syntax/LexicalAndXml/LexicalErrorTests.cs b/src/Compilers/CSharp/Test/Syntax/LexicalAndXml/LexicalErrorTests.cs
@@ -442,27 +442,29 @@ public void DuplicateModifiers_NotReportedDuringParsing()
         {
             // Duplicate modifiers for local declarations and local functions should not produce
             // parsing errors. They will be reported during binding.
-            var localDeclaration = @"
-class C
-{
-    void M()
-    {
-        const const int a = 0;
-    }
-}";
+            var localDeclaration = """
+                class C
+                {
+                    void M()
+                    {
+                        const const int a = 0;
+                    }
+                }
+                """;
             ParserErrorMessageTests.ParseAndValidate(localDeclaration);
 
-            var localFunction = @"
-class C
-{
-    void M()
-    {
-        static static void F() {}
-    }
-}";
+            var localFunction = """
+                class C
+                {
+                    void M()
+                    {
+                        static static void F() {}
+                    }
+                }
+                """;
             ParserErrorMessageTests.ParseAndValidate(localFunction);
 
-            var typeDeclaration = @"public public class C {}";
+            var typeDeclaration = """public public class C {}""";
             ParserErrorMessageTests.ParseAndValidate(typeDeclaration);
         }
 

Original file line number	Diff line number	Diff line change
`@@ -10513,6 +10513,9 @@ private void ParseDeclarationModifiers(SyntaxListBuilder list, bool isUsingDecla`
`10513`	`10513`	`{`
`10514`	`10514`	`mod = this.AddError(mod, ErrorCode.ERR_BadMemberFlag, mod.Text);`
`10515`	`10515`	`}`
	`10516`	`+ // Note: Duplicate modifiers are not reported here during parsing.`
	`10517`	`+ // They will be reported during binding (see Binder_Statements.BindDeclarationStatementParts`
	`10518`	`+ // and ModifierUtils.ToDeclarationModifiers).`
`10516`	`10519`
`10517`	`10520`	`list.Add(mod);`
`10518`	`10521`	`}`