From 7faf1bf1d9aa0f5760163c2539521af51847b292 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Wed, 5 Mar 2025 09:13:52 -0300
Subject: [PATCH] cgen: fix casting primitive type to alias, where option alias
 is expected (fix #23859) (#23860)

---
 vlib/v/gen/c/assign.v                         | 14 ++++++--
 .../options/option_cast_primitive_test.v      | 35 +++++++++++++++++++
 2 files changed, 46 insertions(+), 3 deletions(-)
 create mode 100644 vlib/v/tests/options/option_cast_primitive_test.v

diff --git a/vlib/v/gen/c/assign.v b/vlib/v/gen/c/assign.v
index 602bd24df..d455ea24d 100644
--- a/vlib/v/gen/c/assign.v
+++ b/vlib/v/gen/c/assign.v
@@ -66,18 +66,26 @@ fn (mut g Gen) expr_opt_with_alias(expr ast.Expr, expr_typ ast.Type, ret_typ ast
 	g.writeln('${ret_styp} ${ret_var} = {.state=2, .err=_const_none__, .data={EMPTY_STRUCT_INITIALIZATION}};')
 
 	if expr !is ast.None {
-		g.write('_option_clone((${option_name}*)')
-		has_addr := expr !in [ast.Ident, ast.SelectorExpr]
+		is_option_expr := expr_typ.has_flag(.option)
+		if is_option_expr {
+			g.write('_option_clone((${option_name}*)')
+		} else {
+			g.write('_option_ok(&(${styp}[]){ ')
+		}
+		has_addr := is_option_expr && expr !in [ast.Ident, ast.SelectorExpr]
 		if has_addr {
 			expr_styp := g.styp(expr_typ).replace('*', '_ptr')
 			g.write('ADDR(${expr_styp}, ')
-		} else {
+		} else if is_option_expr {
 			g.write('&')
 		}
 		g.expr(expr)
 		if has_addr {
 			g.write(')')
 		}
+		if !is_option_expr {
+			g.write(' }')
+		}
 		g.writeln(', (${option_name}*)&${ret_var}, sizeof(${styp}));')
 	}
 	g.write(line)
diff --git a/vlib/v/tests/options/option_cast_primitive_test.v b/vlib/v/tests/options/option_cast_primitive_test.v
new file mode 100644
index 000000000..6a5301325
--- /dev/null
+++ b/vlib/v/tests/options/option_cast_primitive_test.v
@@ -0,0 +1,35 @@
+module main
+
+type Float = f32
+
+struct Note {
+mut:
+	seen string
+}
+
+fn (mut n Note) bad_call(value ?Float) {
+	if val := value {
+		n.seen += ', ${val}'
+	}
+}
+
+fn (mut n Note) good_call(value ?f32) {
+	if val := value {
+		n.seen += ', ${val}'
+	}
+}
+
+fn test_main() {
+	mut good := Note{}
+	mut bad := Note{}
+	mut c := 0
+	for {
+		good.good_call(f32(c))
+		bad.bad_call(Float(c))
+		c += 1
+		if c >= 5 {
+			break
+		}
+	}
+	assert '${good.seen}' == '${bad.seen}'
+}
-- 
2.39.5