cgen: fix using brackets for match expression (#6768)

vlib/v/gen/cgen.v

@@ -2820,12 +2820,17 @@ fn (mut g Gen) match_expr(node ast.MatchExpr) {
 	g.expr(node.cond)
 	g.writeln(';')
 	g.write(cur_line)
+	if is_expr {
+		// brackets needed otherwise '?' will apply to everything on the left
+		g.write('(')
+	}
 	if node.is_sum_type {
 		g.match_expr_sumtype(node, is_expr, cond_var)
 	} else {
 		g.match_expr_classic(node, is_expr, cond_var)
 	}
 	if is_expr {
+		g.write(')')
 		g.decrement_inside_ternary()
 	}
 }

vlib/v/tests/match_test.v

@@ -222,3 +222,10 @@ fn test_match_sumtype_multiple_types() {
 		}
 	}
 }
+
+fn test_sub_expression() {
+	b := false && match 1 {0 {true} else {true}}
+	assert !b
+	c := true || match 1 {0 {false} else {false}}
+	assert c
+}