From 585b5145faecec4ea05d31beec7c3374df6ad3ba Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Wed, 22 Jun 2022 19:54:04 +0800
Subject: [PATCH] cgen: fix auto string method generated for []&int{len:1}
 (#14829)

---
 vlib/v/gen/c/auto_str_methods.v              | 12 ++++++++++--
 vlib/v/tests/string_array_of_ref_type_test.v |  5 +++++
 2 files changed, 15 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/tests/string_array_of_ref_type_test.v

diff --git a/vlib/v/gen/c/auto_str_methods.v b/vlib/v/gen/c/auto_str_methods.v
index d4dd58e8b3..f4e92f51af 100644
--- a/vlib/v/gen/c/auto_str_methods.v
+++ b/vlib/v/gen/c/auto_str_methods.v
@@ -586,8 +586,16 @@ fn (mut g Gen) gen_str_for_array(info ast.Array, styp string, str_fn_name string
 			// Note: we need to take account of whether the user has defined
 			// `fn (x T) str() {` or `fn (x &T) str() {`, and convert accordingly
 			deref, deref_label := deref_kind(str_method_expects_ptr, is_elem_ptr, typ)
-			g.auto_str_funcs.writeln('\t\tstrings__Builder_write_string(&sb, _SLIT("$deref_label"));')
-			g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}( $deref it);')
+			if is_elem_ptr {
+				g.auto_str_funcs.writeln('\t\tstring x = _SLIT("nil");')
+				g.auto_str_funcs.writeln('\t\tif (it != 0) {')
+				g.auto_str_funcs.writeln('\t\t\tstrings__Builder_write_string(&sb, _SLIT("$deref_label"));')
+				g.auto_str_funcs.writeln('\t\t\tx = ${elem_str_fn_name}(${deref}it);')
+				g.auto_str_funcs.writeln('\t\t}')
+			} else {
+				g.auto_str_funcs.writeln('\t\tstrings__Builder_write_string(&sb, _SLIT("$deref_label"));')
+				g.auto_str_funcs.writeln('\t\tstring x = ${elem_str_fn_name}(${deref}it);')
+			}
 		}
 	}
 	g.auto_str_funcs.writeln('\t\tstrings__Builder_write_string(&sb, x);')
diff --git a/vlib/v/tests/string_array_of_ref_type_test.v b/vlib/v/tests/string_array_of_ref_type_test.v
new file mode 100644
index 0000000000..abcb2de3d8
--- /dev/null
+++ b/vlib/v/tests/string_array_of_ref_type_test.v
@@ -0,0 +1,5 @@
+fn test_string_array_of_ref_type() {
+	a := []&int{len: 2}
+	println(a)
+	assert '$a' == '[nil, nil]'
+}