cgen: fixevaluation order for match expressions inside boolean ones (fix #16554) (#16616)

vlib/v/gen/c/match.v

@@ -86,6 +86,11 @@ fn (mut g Gen) match_expr(node ast.MatchExpr) {
 		cur_line = g.go_before_stmt(0).trim_left(' \t')
 		tmp_var = g.new_tmp_var()
 		g.writeln('${g.typ(node.return_type)} ${tmp_var} = ${g.type_default(node.return_type)};')
+		g.empty_line = true
+		if g.infix_left_var_name.len > 0 {
+			g.writeln('if (${g.infix_left_var_name}) {')
+			g.indent++
+		}
 	}
 
 	if is_expr && !need_tmp_var {
@@ -125,6 +130,14 @@ fn (mut g Gen) match_expr(node ast.MatchExpr) {
 		}
 	}
 	g.set_current_pos_as_last_stmt_pos()
+	if need_tmp_var {
+		if g.infix_left_var_name.len > 0 {
+			g.writeln('')
+			g.indent--
+			g.writeln('}')
+			g.set_current_pos_as_last_stmt_pos()
+		}
+	}
 	g.write(cur_line)
 	if need_tmp_var {
 		g.write('${tmp_var}')

vlib/v/tests/match_expr_skip_in_infix_expr_test.v

@@ -0,0 +1,33 @@
+fn test_match_expr_skip_in_infix_expr_1() {
+	mut a := false
+	b := a && match true {
+		true {
+			a = true
+			true
+		}
+		false {
+			false
+		}
+	}
+	println(a)
+	assert a == false
+	println(b)
+	assert b == false
+}
+
+fn test_match_expr_skip_in_infix_expr_2() {
+	mut a := true
+	b := a || match true {
+		true {
+			a = false
+			true
+		}
+		false {
+			false
+		}
+	}
+	println(a)
+	assert a == true
+	println(b)
+	assert b == true
+}