Fixes Some Issue to pass other testcases

Author: abulgit

compiler/src/dmd/funcsem.d

@@ -984,24 +984,20 @@ void funcDeclarationSemantic(Scope* sc, FuncDeclaration funcdecl)
                         error(funcdecl.loc, "function `%s` does not override any function, did you mean to override `%s`?",
                             funcdeclToChars, buf1.peekChars());
 
-                        // A more detailed error message showing the difference between signatures
+                        // Only add supplemental error for parameter scope differences
                         auto tf1 = cast(TypeFunction)funcdecl.type;
                         auto tf2 = cast(TypeFunction)fd.type;
 
-                        // Only show diff if both are function types
                         if (tf1 && tf2)
                         {
-                            // Get parameter lists
                             auto params1 = tf1.parameterList;
                             auto params2 = tf2.parameterList;
 
-                            // Show the function signature that would be correct
-                            errorSupplemental(funcdecl.loc, "Did you intend to override:");
-                            errorSupplemental(funcdecl.loc, "`%s`", buf1.peekChars());
-
-                            // If parameter counts match, show detailed diff for each parameter
+                            // Only check for scope differences if parameter counts match
                             if (params1.length == params2.length)
                             {
+                                bool hasScopeDifference = false;
+                                
                                 for (size_t i = 0; i < params1.length; i++)
                                 {
                                     auto p1 = params1[i];
@@ -1011,16 +1007,19 @@ void funcDeclarationSemantic(Scope* sc, FuncDeclaration funcdecl)
                                     if ((p1.storageClass & STC.scope_) != (p2.storageClass & STC.scope_))
                                     {
                                         if (p2.storageClass & STC.scope_)
+                                        {
+                                            if (!hasScopeDifference)
+                                            {
+                                                // Only show the intended signature once
+                                                errorSupplemental(funcdecl.loc, "Did you intend to override:");
+                                                errorSupplemental(funcdecl.loc, "`%s`", buf1.peekChars());
+                                                hasScopeDifference = true;
+                                            }
                                             errorSupplemental(funcdecl.loc, "Parameter %d is missing `scope`", cast(int)(i + 1));
+                                        }
                                     }
                                 }
                             }
-                            else
-                            {
-                                // If parameter counts don't match, show that
-                                errorSupplemental(funcdecl.loc, "Parameter count mismatch: %d vs %d",
-                                    cast(int)params1.length, cast(int)params2.length);
-                            }
                         }
                    }
                 }

compiler/test/fail_compilation/test20489.d

@@ -1,42 +1,21 @@
 /*
+REQUIRED_ARGS: -verrors=0
 TEST_OUTPUT:
 ---
-fail_compilation/test20489.d(23): Error: function `pure nothrow @nogc @safe int test20489.D1.f(int delegate(int) pure nothrow @nogc @safe body)` does not override any function, did you mean to override `pure nothrow @nogc @safe int test20489.B1.f(scope int delegate(int) pure nothrow @nogc @safe)`?
-fail_compilation/test20489.d(23):        Did you intend to override:
-fail_compilation/test20489.d(23):        `pure nothrow @nogc @safe int test20489.B1.f(scope int delegate(int) pure nothrow @nogc @safe)`
-fail_compilation/test20489.d(23):        Parameter 1 is missing `scope`
-fail_compilation/test20489.d(32): Error: function `test20489.D2.nonExistentMethod` does not override any function
-fail_compilation/test20489.d(41): Error: function `test20489.D3.finalMethod` cannot override `final` function `test20489.B3.finalMethod`
-fail_compilation/test20489.d(41): Error: function `void test20489.D3.finalMethod()` does not override any function, did you mean to override `void test20489.B3.finalMethod()`?
-fail_compilation/test20489.d(41):        Did you intend to override:
-fail_compilation/test20489.d(41):        `void test20489.B3.finalMethod()`
+fail_compilation/test20489.d(20): Error: function `pure nothrow @nogc @safe int test20489.D.f(int delegate(int) pure nothrow @nogc @safe body)` does not override any function, did you mean to override `pure nothrow @nogc @safe int test20489.B.f(scope int delegate(int) pure nothrow @nogc @safe)`?
+fail_compilation/test20489.d(20):        Did you intend to override:
+fail_compilation/test20489.d(20):        `pure nothrow @nogc @safe int test20489.B.f(scope int delegate(int) pure nothrow @nogc @safe)`
+fail_compilation/test20489.d(20):        Parameter 1 is missing `scope`
 ---
 */
 
+// Test case for https://issues.dlang.org/show_bug.cgi?id=20489
+// Improved error message for override mismatches
 
-// Case 1: Signature mismatch (parameter attributes)
-class B1 {
+class B {
     pure nothrow @nogc @safe int f(scope int delegate(int) pure nothrow @nogc @safe) { return 0; }
 }
 
-class D1 : B1 {
+class D : B {
     override pure nothrow @nogc @safe int f(int delegate(int) pure nothrow @nogc @safe body) { return 0; }
 }
-
-// Case 2: No base class method with the given name exists
-class B2 {
-    void existingMethod() {}
-}
-
-class D2 : B2 {
-    override void nonExistentMethod() {}
-}
-
-// Case 3: Base class method is final
-class B3 {
-    final void finalMethod() {}
-}
-
-class D3 : B3 {
-    override void finalMethod() {}
-}