From 77e45946f2a197462d5c7f7f7237ac2915bdfa9c Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Wed, 11 Dec 2024 11:07:39 -0300
Subject: [PATCH] cgen: fix different option alias type as fn arg (fix #23086)
 (#23131)

---
 vlib/v/gen/c/assign.v                         | 57 ++++++++++++++-----
 vlib/v/gen/c/fn.v                             |  6 +-
 .../options/option_diff_alias_arg_test.v      | 18 ++++++
 3 files changed, 65 insertions(+), 16 deletions(-)
 create mode 100644 vlib/v/tests/options/option_diff_alias_arg_test.v

diff --git a/vlib/v/gen/c/assign.v b/vlib/v/gen/c/assign.v
index f05fbc719..de19911bf 100644
--- a/vlib/v/gen/c/assign.v
+++ b/vlib/v/gen/c/assign.v
@@ -54,6 +54,38 @@ fn (mut g Gen) expr_with_opt_or_block(expr ast.Expr, expr_typ ast.Type, var_expr
 	}
 }
 
+// expr_opt_with_alias handles conversion from different option alias type name
+fn (mut g Gen) expr_opt_with_alias(expr ast.Expr, expr_typ ast.Type, ret_typ ast.Type, tmp_var string) string {
+	styp := g.base_type(ret_typ)
+
+	line := g.go_before_last_stmt().trim_space()
+	g.empty_line = true
+
+	ret_var := g.new_tmp_var()
+	ret_styp := g.styp(ret_typ).replace('*', '_ptr')
+	g.writeln('${ret_styp} ${ret_var} = {0};')
+
+	g.write('_option_clone((${option_name}*)')
+	has_addr := expr !in [ast.Ident, ast.SelectorExpr]
+	if has_addr {
+		expr_styp := g.styp(expr_typ).replace('*', '_ptr')
+		g.write('ADDR(${expr_styp}, ')
+	} else {
+		g.write('&')
+	}
+	g.expr(expr)
+	if has_addr {
+		g.write(')')
+	}
+	g.writeln(', (${option_name}*)&${ret_var}, sizeof(${styp}));')
+	g.write(line)
+	if g.inside_return {
+		g.write(' ')
+	}
+	g.write(ret_var)
+	return ret_var
+}
+
 // expr_opt_with_cast is used in cast expr when converting compatible option types
 // e.g. ?int(?u8(0))
 fn (mut g Gen) expr_opt_with_cast(expr ast.Expr, expr_typ ast.Type, ret_typ ast.Type) string {
@@ -64,22 +96,17 @@ fn (mut g Gen) expr_opt_with_cast(expr ast.Expr, expr_typ ast.Type, ret_typ ast.
 	if expr_typ.idx() == ret_typ.idx() && g.table.sym(expr_typ).kind != .alias {
 		return g.expr_with_opt(expr, expr_typ, ret_typ)
 	} else {
-		past := g.past_tmp_var_new()
-		defer {
-			g.past_tmp_var_done(past)
-		}
-		styp := g.base_type(ret_typ)
-		decl_styp := g.styp(ret_typ).replace('*', '_ptr')
-		g.writeln('${decl_styp} ${past.tmp_var};')
-		is_none := expr is ast.CastExpr && expr.expr is ast.None
 		if expr is ast.CallExpr && expr.return_type.has_flag(.option) {
-			tmp_var := g.new_tmp_var()
-			ret_styp := g.styp(expr.return_type).replace('*', '_ptr')
-			g.write('${ret_styp} ${tmp_var} = ')
-			g.expr(expr)
-			g.writeln(';')
-			g.writeln('_option_clone(&${tmp_var}, (${option_name}*)(&${past.tmp_var}), sizeof(${styp}));')
+			return g.expr_opt_with_alias(expr, expr_typ, ret_typ, '')
 		} else {
+			past := g.past_tmp_var_new()
+			defer {
+				g.past_tmp_var_done(past)
+			}
+			styp := g.base_type(ret_typ)
+			decl_styp := g.styp(ret_typ).replace('*', '_ptr')
+			g.writeln('${decl_styp} ${past.tmp_var};')
+			is_none := expr is ast.CastExpr && expr.expr is ast.None
 			if is_none {
 				g.write('_option_none(&(${styp}[]) {')
 			} else {
@@ -96,8 +123,8 @@ fn (mut g Gen) expr_opt_with_cast(expr ast.Expr, expr_typ ast.Type, ret_typ ast.
 				g.inside_opt_or_res = old_inside_opt_or_res
 			}
 			g.writeln(' }, (${option_name}*)(&${past.tmp_var}), sizeof(${styp}));')
+			return past.tmp_var
 		}
-		return past.tmp_var
 	}
 }
 
diff --git a/vlib/v/gen/c/fn.v b/vlib/v/gen/c/fn.v
index ad41726ba..92ee090eb 100644
--- a/vlib/v/gen/c/fn.v
+++ b/vlib/v/gen/c/fn.v
@@ -2946,7 +2946,11 @@ fn (mut g Gen) ref_or_deref_arg(arg ast.CallArg, expected_type ast.Type, lang as
 		g.write('->val')
 		return
 	} else if expected_type.has_flag(.option) {
-		g.expr_with_opt(arg.expr, arg_typ, expected_type)
+		if arg_sym.info is ast.Alias && expected_type != arg_typ {
+			g.expr_opt_with_alias(arg.expr, arg_typ, expected_type, '')
+		} else {
+			g.expr_with_opt(arg.expr, arg_typ, expected_type)
+		}
 		return
 	} else if arg.expr is ast.ArrayInit {
 		if arg.expr.is_fixed {
diff --git a/vlib/v/tests/options/option_diff_alias_arg_test.v b/vlib/v/tests/options/option_diff_alias_arg_test.v
new file mode 100644
index 000000000..fc17c6ab1
--- /dev/null
+++ b/vlib/v/tests/options/option_diff_alias_arg_test.v
@@ -0,0 +1,18 @@
+import time
+
+struct Foo[T] {
+pub:
+	value ?T
+}
+
+fn t(x ?i64) i64 {
+	return x or { -1 }
+}
+
+fn test_main() {
+	bar := Foo[time.Duration]{
+		value: time.Duration(0)
+	}
+
+	assert t(bar.value) == 0
+}
-- 
2.39.5