From efb78cea35bb24711fbbb47571e92fd80363a61c Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 15 Apr 2026 04:51:55 +0300
Subject: [PATCH] checker: fix cannot convert struct to struct pointer in
 generics (fixes #21835)

---
 vlib/v/checker/check_types.v                  | 13 +++++++++++-
 ...ort_struct_init_reference_inference_test.v | 21 +++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/tests/generics/generic_fn_short_struct_init_reference_inference_test.v

diff --git a/vlib/v/checker/check_types.v b/vlib/v/checker/check_types.v
index 1f8d1e24f..24b47628a 100644
--- a/vlib/v/checker/check_types.v
+++ b/vlib/v/checker/check_types.v
@@ -1142,9 +1142,20 @@ fn (mut c Checker) infer_struct_generic_types(typ ast.Type, node ast.StructInit)
 						if ft.name == t.name && t.typ != 0 {
 							// unwrap to get base type for T if both are options
 							mut inferred_typ := ast.mktyp(t.typ)
-							if ft.typ.has_flag(.option) && inferred_typ.has_flag(.option) {
+							mut field_typ := ft.typ
+							if field_typ.has_flag(.option) && inferred_typ.has_flag(.option) {
+								field_typ = field_typ.clear_flag(.option)
 								inferred_typ = inferred_typ.clear_flag(.option)
 							}
+							if field_typ.nr_muls() > 0 && inferred_typ.nr_muls() > 0 {
+								field_muls := field_typ.nr_muls()
+								inferred_muls := inferred_typ.nr_muls()
+								inferred_typ = if inferred_muls >= field_muls {
+									inferred_typ.set_nr_muls(inferred_muls - field_muls)
+								} else {
+									inferred_typ.set_nr_muls(0)
+								}
+							}
 							concrete_types << inferred_typ
 							continue gname
 						}
diff --git a/vlib/v/tests/generics/generic_fn_short_struct_init_reference_inference_test.v b/vlib/v/tests/generics/generic_fn_short_struct_init_reference_inference_test.v
new file mode 100644
index 000000000..f921e88b5
--- /dev/null
+++ b/vlib/v/tests/generics/generic_fn_short_struct_init_reference_inference_test.v
@@ -0,0 +1,21 @@
+import json
+
+@[heap]
+struct Logger {}
+
+struct SaveParams[T] {
+	object &T
+}
+
+fn (mut l Logger) save[T](p SaveParams[T]) string {
+	return json.encode(p.object)
+}
+
+struct Object {
+	s1 string = 'a string'
+}
+
+fn test_generic_fn_short_struct_init_reference_inference() {
+	mut logger := &Logger{}
+	assert logger.save(object: &Object{}) == '{"s1":"a string"}'
+}
-- 
2.39.5