gopls/go/pointer/testdata/arrayreflect.go

1	//go:build ignore
2	// +build ignore
3
4	package main
5
6	// Test of arrays & slices with reflection.
7
8	import "reflect"
9
10	var a, b int
11
12	type S string
13
14	func reflectValueSlice() {
15	// reflect.Value contains a slice.
16	slice := make([]*int, 10) // @line slice
17	slice[0] = &a
18	rvsl := reflect.ValueOf(slice).Slice(0, 0)
19	print(rvsl.Interface()) // @types []*int
20	print(rvsl.Interface().([]*int)) // @pointsto makeslice@slice:15
21	print(rvsl.Interface().([]*int)[42]) // @pointsto command-line-arguments.a
22
23	// reflect.Value contains an array (non-addressable).
24	array := [10]*int{&a} // @line array
25	rvarray := reflect.ValueOf(array).Slice(0, 0)
26	print(rvarray.Interface()) // @types
27	print(rvarray.Interface().([]*int)) // @pointsto
28	print(rvarray.Interface().([]*int)[42]) // @pointsto
29
30	// reflect.Value contains a pointer-to-array
31	rvparray := reflect.ValueOf(&array).Slice(0, 0)
32	print(rvparray.Interface()) // @types []*int
33	print(rvparray.Interface().([]*int)) // @pointsto array@array:2
34	print(rvparray.Interface().([]*int)[42]) // @pointsto command-line-arguments.a
35
36	// reflect.Value contains a string.
37	rvstring := reflect.ValueOf("hi").Slice(0, 0)
38	print(rvstring.Interface()) // @types string
39
40	// reflect.Value contains a (named) string type.
41	rvS := reflect.ValueOf(S("hi")).Slice(0, 0)
42	print(rvS.Interface()) // @types S
43
44	// reflect.Value contains a non-array pointer.
45	rvptr := reflect.ValueOf(new(int)).Slice(0, 0)
46	print(rvptr.Interface()) // @types
47
48	// reflect.Value contains a non-string basic type.
49	rvint := reflect.ValueOf(3).Slice(0, 0)
50	print(rvint.Interface()) // @types
51	}
52
53	func reflectValueBytes() {
54	sl1 := make([]byte, 0) // @line ar5sl1
55	sl2 := make([]byte, 0) // @line ar5sl2
56
57	rvsl1 := reflect.ValueOf(sl1)
58	print(rvsl1.Interface()) // @types []byte
59	print(rvsl1.Interface().([]byte)) // @pointsto makeslice@ar5sl1:13
60	print(rvsl1.Bytes()) // @pointsto makeslice@ar5sl1:13
61
62	rvsl2 := reflect.ValueOf(123)
63	rvsl2.SetBytes(sl2)
64	print(rvsl2.Interface()) // @types int
65	print(rvsl2.Interface().([]byte)) // @pointsto
66	print(rvsl2.Bytes()) // @pointsto
67
68	rvsl3 := reflect.ValueOf([]byte(nil))
69	rvsl3.SetBytes(sl2)
70	print(rvsl3.Interface()) // @types []byte
71	print(rvsl3.Interface().([]byte)) // @pointsto makeslice@ar5sl2:13
72	print(rvsl3.Bytes()) // @pointsto makeslice@ar5sl2:13
73	}
74
75	func reflectValueIndex() {
76	slice := []*int{&a} // @line ar6slice
77	rv1 := reflect.ValueOf(slice)
78	print(rv1.Index(42).Interface()) // @types *int
79	print(rv1.Index(42).Interface().(*int)) // @pointsto command-line-arguments.a
80
81	array := [10]*int{&a}
82	rv2 := reflect.ValueOf(array)
83	print(rv2.Index(42).Interface()) // @types *int
84	print(rv2.Index(42).Interface().(*int)) // @pointsto command-line-arguments.a
85
86	rv3 := reflect.ValueOf("string")
87	print(rv3.Index(42).Interface()) // @types rune
88
89	rv4 := reflect.ValueOf(&array)
90	print(rv4.Index(42).Interface()) // @types
91
92	rv5 := reflect.ValueOf(3)
93	print(rv5.Index(42).Interface()) // @types
94	}
95
96	func reflectValueElem() {
97	// Interface.
98	var iface interface{} = &a
99	rv1 := reflect.ValueOf(&iface).Elem()
100	print(rv1.Interface()) // @types *int
101	print(rv1.Interface().(*int)) // @pointsto command-line-arguments.a
102	print(rv1.Elem().Interface()) // @types *int
103	print(rv1.Elem().Interface().(*int)) // @pointsto command-line-arguments.a
104
105	print(reflect.ValueOf(new(interface{})).Elem().Elem()) // @types
106
107	// Pointer.
108	ptr := &a
109	rv2 := reflect.ValueOf(&ptr)
110	print(rv2.Elem().Interface()) // @types *int
111	print(rv2.Elem().Interface().(*int)) // @pointsto command-line-arguments.a
112
113	// No other type works with (rV).Elem, not even those that
114	// work with (rT).Elem: slice, array, map, chan.
115
116	rv3 := reflect.ValueOf([]*int{&a})
117	print(rv3.Elem().Interface()) // @types
118
119	rv4 := reflect.ValueOf([10]*int{&a})
120	print(rv4.Elem().Interface()) // @types
121
122	rv5 := reflect.ValueOf(map[int]int{&a: &b})
123	print(rv5.Elem().Interface()) // @types
124
125	ch := make(chan *int)
126	ch <- &a
127	rv6 := reflect.ValueOf(ch)
128	print(rv6.Elem().Interface()) // @types
129
130	rv7 := reflect.ValueOf(3)
131	print(rv7.Elem().Interface()) // @types
132	}
133
134	func reflectTypeElem() {
135	rt1 := reflect.TypeOf(make([]*int, 0))
136	print(reflect.Zero(rt1.Elem())) // @types *int
137
138	rt2 := reflect.TypeOf([10]*int{})
139	print(reflect.Zero(rt2.Elem())) // @types *int
140
141	rt3 := reflect.TypeOf(map[int]int{})
142	print(reflect.Zero(rt3.Elem())) // @types *int
143
144	rt4 := reflect.TypeOf(make(chan *int))
145	print(reflect.Zero(rt4.Elem())) // @types *int
146
147	ptr := &a
148	rt5 := reflect.TypeOf(&ptr)
149	print(reflect.Zero(rt5.Elem())) // @types *int
150
151	rt6 := reflect.TypeOf(3)
152	print(reflect.Zero(rt6.Elem())) // @types
153	}
154
155	func reflectPtrTo() {
156	tInt := reflect.TypeOf(3)
157	tPtrInt := reflect.PtrTo(tInt)
158	print(reflect.Zero(tPtrInt)) // @types *int
159	tPtrPtrInt := reflect.PtrTo(tPtrInt)
160	print(reflect.Zero(tPtrPtrInt)) // @types **int
161	}
162
163	func reflectSliceOf() {
164	tInt := reflect.TypeOf(3)
165	tSliceInt := reflect.SliceOf(tInt)
166	print(reflect.Zero(tSliceInt)) // @types []int
167	}
168
169	type T struct{ x int }
170
171	func reflectMakeSlice() {
172	rt := []reflect.Type{
173	reflect.TypeOf(3),
174	reflect.TypeOf([]int{}),
175	reflect.TypeOf([]T{}),
176	}[0]
177	sl := reflect.MakeSlice(rt, 0, 0)
178	print(sl) // @types []int \| []T
179	print(sl) // @pointsto <alloc in reflect.MakeSlice> \| <alloc in reflect.MakeSlice>
180	print(&sl.Interface().([]T)[0].x) // @pointsto <alloc in reflect.MakeSlice>[*].x
181	}
182
183	func main() {
184	reflectValueSlice()
185	reflectValueBytes()
186	reflectValueIndex()
187	reflectValueElem()
188	reflectTypeElem()
189	reflectPtrTo()
190	reflectSliceOf()
191	reflectMakeSlice()
192	}
193