From 373e5abb4755c4cc7b4d342b0482853ef981dbcd Mon Sep 17 00:00:00 2001
From: CreeperFace <165158232+dy-tea@users.noreply.github.com>
Date: Mon, 15 Sep 2025 17:08:53 +0100
Subject: [PATCH] markused: fix marking of mutable generic method calls (fix
 #25312) (#25314)

---
 vlib/v/markused/walker.v                      | 15 +++++++++++
 .../generic_fn_multi_mutable_struct_test.v    | 26 +++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 vlib/v/tests/generics/generic_fn_multi_mutable_struct_test.v

diff --git a/vlib/v/markused/walker.v b/vlib/v/markused/walker.v
index e16a17eab..263d3e65e 100644
--- a/vlib/v/markused/walker.v
+++ b/vlib/v/markused/walker.v
@@ -35,6 +35,7 @@ mut:
 	all_decltypes map[string]ast.TypeDecl
 	all_structs   map[string]ast.StructDecl
 
+	cur_fn                 string
 	level                  int
 	is_builtin_mod         bool
 	is_direct_array_access bool
@@ -934,6 +935,7 @@ pub fn (mut w Walker) fn_decl(mut node ast.FnDecl) {
 	}
 	w.mark_fn_ret_and_params(node.return_type, node.params)
 	w.mark_fn_as_used(fkey)
+	w.cur_fn = fkey
 	w.stmts(node.stmts)
 	w.defer_stmts(node.defer_stmts)
 }
@@ -989,6 +991,19 @@ pub fn (mut w Walker) call_expr(mut node ast.CallExpr) {
 				fn_embed := '${int(embed_types.last())}.${node.name}'
 				w.fn_by_name(fn_embed)
 			}
+		} else if node.left_type.has_flag(.generic) {
+			if w.cur_fn != '' {
+				if concrete_types_list := w.table.fn_generic_types[w.cur_fn] {
+					for concrete_types in concrete_types_list {
+						for concrete_type in concrete_types {
+							method_name := '${int(concrete_type)}.${node.name}'
+							if !w.used_fns[method_name] {
+								w.fn_by_name(method_name)
+							}
+						}
+					}
+				}
+			}
 		} else {
 			match left_sym.info {
 				ast.Array, ast.ArrayFixed {
diff --git a/vlib/v/tests/generics/generic_fn_multi_mutable_struct_test.v b/vlib/v/tests/generics/generic_fn_multi_mutable_struct_test.v
new file mode 100644
index 000000000..63936f9a1
--- /dev/null
+++ b/vlib/v/tests/generics/generic_fn_multi_mutable_struct_test.v
@@ -0,0 +1,26 @@
+struct Aa {
+}
+
+fn (aa Aa) dump() {
+	println(aa)
+}
+
+struct Bb {
+}
+
+fn (bb Bb) dump() {
+	println(bb)
+}
+
+struct Foo {
+}
+
+fn (foo Foo) set[T](mut obj T) {
+	obj.dump()
+}
+
+fn test_main() {
+	f := Foo{}
+	f.set(mut Aa{})
+	f.set(mut Bb{})
+}
-- 
2.39.5