From 42777f0125261bf0fe7934b3d053f6c21ba2cc46 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 23 Aug 2025 17:44:05 -0300
Subject: [PATCH] cgen, markused: fix veb alias type identification and generic
 CastExpr (fix #24895) (#25155)

---
 vlib/v/checker/checker.v                          |  4 +++-
 vlib/v/checker/fn.v                               |  2 +-
 vlib/v/markused/walker.v                          |  2 +-
 .../tests/generics/generic_alias_callback_test.v  | 15 +++++++++++++++
 4 files changed, 20 insertions(+), 3 deletions(-)
 create mode 100644 vlib/v/tests/generics/generic_alias_callback_test.v

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index b0b08fc09..fd9d854d4 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -3388,7 +3388,9 @@ fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 	//        node.expr_type: `Inside`
 	//        node.typ: `Outside`
 	mut to_type := c.unwrap_generic(node.typ)
-
+	if node.typ.has_flag(.generic) {
+		c.table.used_features.comptime_syms[to_type] = true
+	}
 	old_inside_integer_literal_cast := c.inside_integer_literal_cast
 	c.inside_integer_literal_cast = to_type.is_int() && node.expr is ast.IntegerLiteral
 	node.expr_type = c.expr(mut node.expr) // type to be casted
diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index 73f27910a..69eff4fea 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -3936,7 +3936,7 @@ fn (mut c Checker) check_must_use_call_result(node &ast.CallExpr, f &ast.Fn, lab
 }
 
 fn (mut c Checker) has_veb_context(typ ast.Type) bool {
-	sym := c.table.sym(typ)
+	sym := c.table.final_sym(typ)
 	if sym.name == 'veb.Context' {
 		return true
 	} else if sym.info is ast.Struct {
diff --git a/vlib/v/markused/walker.v b/vlib/v/markused/walker.v
index bdf66037e..a2156e7a4 100644
--- a/vlib/v/markused/walker.v
+++ b/vlib/v/markused/walker.v
@@ -1377,7 +1377,7 @@ fn (mut w Walker) mark_resource_dependencies() {
 	if w.trace_enabled {
 		ptypes := w.table.used_features.print_types.keys().map(w.table.type_to_str(it))
 		eprintln('>>>>>>>>>> PRINT TYPES ${ptypes}')
-		stypes := w.uses_str.keys().map(w.table.type_to_str(it))
+		stypes := w.uses_str.keys().filter(it != 0).map(w.table.type_to_str(it))
 		eprintln('>>>>>>>>>> USES .str() CALLS ON TYPES ${stypes}')
 		ftypes := w.uses_free.keys().map(w.table.type_to_str(it))
 		eprintln('>>>>>>>>>> USES .free() CALLS ON TYPES ${ftypes}')
diff --git a/vlib/v/tests/generics/generic_alias_callback_test.v b/vlib/v/tests/generics/generic_alias_callback_test.v
new file mode 100644
index 000000000..d69f1d0a3
--- /dev/null
+++ b/vlib/v/tests/generics/generic_alias_callback_test.v
@@ -0,0 +1,15 @@
+struct Foo[T] {
+	val T
+}
+
+type Bar[T] = fn (T) bool
+
+fn t[T](val T) {
+	_ := Bar[T](fn [T](a T) bool {
+		return true
+	})
+}
+
+fn test_main() {
+	t[int](1)
+}
-- 
2.39.5