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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vardecl
// Prerequisites.
import "math"
func f() {}
func g() (x, y int) { return }
var m map[string]int
// Var decls must have a type or an initializer.
var _ int
var _, _ int
var _ /* ERROR "expecting type" */
var _, _ /* ERROR "expecting type" */
var _, _, _ /* ERROR "expecting type" */
// The initializer must be an expression.
var _ = int /* ERROR "not an expression" */
var _ = f /* ERROR "used as value" */ ()
// Identifier and expression arity must match.
var _, _ = 1, 2
var _ = 1, 2 /* ERROR "extra init expr 2" */
var _, _ = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
var _, _, _ /* ERROR "missing init expr for _" */ = 1, 2
var _ = g /* ERROR "2-valued g" */ ()
var _, _ = g()
var _, _, _ = g /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ()
var _ = m["foo"]
var _, _ = m["foo"]
var _, _, _ = m /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ["foo"]
var _, _ int = 1, 2
var _ int = 1, 2 /* ERROR "extra init expr 2" */
var _, _ int = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
var _, _, _ /* ERROR "missing init expr for _" */ int = 1, 2
var (
_, _ = 1, 2
_ = 1, 2 /* ERROR "extra init expr 2" */
_, _ = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
_, _, _ /* ERROR "missing init expr for _" */ = 1, 2
_ = g /* ERROR "2-valued g" */ ()
_, _ = g()
_, _, _ = g /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ()
_ = m["foo"]
_, _ = m["foo"]
_, _, _ = m /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ["foo"]
_, _ int = 1, 2
_ int = 1, 2 /* ERROR "extra init expr 2" */
_, _ int = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
_, _, _ /* ERROR "missing init expr for _" */ int = 1, 2
)
// Variables declared in function bodies must be 'used'.
type T struct{}
func (r T) _(a, b, c int) (u, v, w int) {
var x1 /* ERROR "declared but not used" */ int
var x2 /* ERROR "declared but not used" */ int
x1 = 1
(x2) = 2
y1 /* ERROR "declared but not used" */ := 1
y2 /* ERROR "declared but not used" */ := 2
y1 = 1
(y1) = 2
{
var x1 /* ERROR "declared but not used" */ int
var x2 /* ERROR "declared but not used" */ int
x1 = 1
(x2) = 2
y1 /* ERROR "declared but not used" */ := 1
y2 /* ERROR "declared but not used" */ := 2
y1 = 1
(y1) = 2
}
if x /* ERROR "declared but not used" */ := 0; a < b {}
switch x /* ERROR "declared but not used" */, y := 0, 1; a {
case 0:
_ = y
case 1:
x /* ERROR "declared but not used" */ := 0
}
var t interface{}
switch t /* ERROR "declared but not used" */ := t.(type) {}
switch t /* ERROR "declared but not used" */ := t.(type) {
case int:
}
switch t /* ERROR "declared but not used" */ := t.(type) {
case int:
case float32, complex64:
t = nil
}
switch t := t.(type) {
case int:
case float32, complex64:
_ = t
}
switch t := t.(type) {
case int:
case float32:
case string:
_ = func() string {
return t
}
}
switch t := t; t /* ERROR "declared but not used" */ := t.(type) {}
var z1 /* ERROR "declared but not used" */ int
var z2 int
_ = func(a, b, c int) (u, v, w int) {
z1 = a
(z1) = b
a = z2
return
}
var s []int
var i /* ERROR "declared but not used" */ , j int
for i, j = range s {
_ = j
}
for i, j /* ERROR "declared but not used" */ := range s {
_ = func() int {
return i
}
}
return
}
// Unused variables in function literals must lead to only one error (issue #22524).
func _() {
_ = func() {
var x /* ERROR declared but not used */ int
}
}
// Invalid variable declarations must not lead to "declared but not used errors".
func _() {
var a x // ERROR undeclared name: x
var b = x // ERROR undeclared name: x
var c int = x // ERROR undeclared name: x
var d, e, f x /* ERROR x */ /* ERROR x */ /* ERROR x */
var g, h, i = x, x, x /* ERROR x */ /* ERROR x */ /* ERROR x */
var j, k, l float32 = x, x, x /* ERROR x */ /* ERROR x */ /* ERROR x */
// but no "declared but not used" errors
}
// Invalid (unused) expressions must not lead to spurious "declared but not used errors".
func _() {
var a, b, c int
var x, y int
x, y = a /* ERROR cannot assign [0-9]+ values to [0-9]+ variables */ , b, c
_ = x
_ = y
}
func _() {
var x int
return x /* ERROR no result values expected */
return math /* ERROR no result values expected */ .Sin(0)
}
func _() int {
var x, y int
return /* ERROR wrong number of return values */ x, y
}
// Short variable declarations must declare at least one new non-blank variable.
func _() {
_ := /* ERROR no new variables */ 0
_, a := 0, 1
_, a := /* ERROR no new variables */ 0, 1
_, a, b := 0, 1, 2
_, _, _ := /* ERROR no new variables */ 0, 1, 2
_ = a
_ = b
}
// Test case for variables depending on function literals (see also #22992).
var A /* ERROR initialization cycle */ = func() int { return A }()
func _() {
// The function literal below must not see a.
var a = func() int { return a /* ERROR "undeclared name" */ }()
var _ = func() int { return a }()
// The function literal below must not see x, y, or z.
var x, y, z = 0, 1, func() int { return x /* ERROR "undeclared name" */ + y /* ERROR "undeclared name" */ + z /* ERROR "undeclared name" */ }()
_, _, _ = x, y, z
}
// TODO(gri) consolidate other var decl checks in this file
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