From 0f3a395ca2849eeb63c7dc6cb3ec6ddcbe255229 Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Fri, 9 Sep 2022 16:29:21 +0800
Subject: [PATCH] checker, cgen: fix if expr with result (#15709)

---
 vlib/v/checker/if.v                     |  2 +-
 vlib/v/gen/c/if.v                       |  6 +++++-
 vlib/v/tests/if_expr_with_result_test.v | 17 +++++++++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/tests/if_expr_with_result_test.v

diff --git a/vlib/v/checker/if.v b/vlib/v/checker/if.v
index d36437bf4e1503..2af8b14868a9f5 100644
--- a/vlib/v/checker/if.v
+++ b/vlib/v/checker/if.v
@@ -188,7 +188,7 @@ pub fn (mut c Checker) if_expr(mut node ast.IfExpr) ast.Type {
 					}
 				}
 				c.expected_type = former_expected_type
-				if c.expected_type.has_flag(.optional) {
+				if c.expected_type.has_flag(.optional) || c.expected_type.has_flag(.result) {
 					if node.typ == ast.void_type {
 						node.is_expr = true
 						node.typ = c.expected_type
diff --git a/vlib/v/gen/c/if.v b/vlib/v/gen/c/if.v
index 6a05c72ed8bd91..9b2136901464cb 100644
--- a/vlib/v/gen/c/if.v
+++ b/vlib/v/gen/c/if.v
@@ -7,7 +7,7 @@ import v.ast
 
 fn (mut g Gen) need_tmp_var_in_if(node ast.IfExpr) bool {
 	if node.is_expr && g.inside_ternary == 0 {
-		if g.is_autofree || node.typ.has_flag(.optional) {
+		if g.is_autofree || node.typ.has_flag(.optional) || node.typ.has_flag(.result) {
 			return true
 		}
 		for branch in node.branches {
@@ -142,6 +142,8 @@ fn (mut g Gen) if_expr(node ast.IfExpr) {
 	if needs_tmp_var {
 		if node.typ.has_flag(.optional) {
 			g.inside_if_optional = true
+		} else if node.typ.has_flag(.result) {
+			g.inside_if_result = true
 		}
 		styp := g.typ(node.typ)
 		cur_line = g.go_before_stmt(0)
@@ -325,5 +327,7 @@ fn (mut g Gen) if_expr(node ast.IfExpr) {
 	}
 	if node.typ.has_flag(.optional) {
 		g.inside_if_optional = false
+	} else if node.typ.has_flag(.result) {
+		g.inside_if_result = false
 	}
 }
diff --git a/vlib/v/tests/if_expr_with_result_test.v b/vlib/v/tests/if_expr_with_result_test.v
new file mode 100644
index 00000000000000..83eaddbb2606f9
--- /dev/null
+++ b/vlib/v/tests/if_expr_with_result_test.v
@@ -0,0 +1,17 @@
+fn foo(i int) ?bool {
+	return if i == 0 { true } else { none }
+}
+
+fn bar(i int) !bool {
+	return if i == 0 { true } else { error('') }
+}
+
+fn test_if_expr_with_result() {
+	r1 := foo(0) or { false }
+	println(r1)
+	assert r1
+
+	r2 := bar(0) or { false }
+	println(r2)
+	assert r2
+}