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Diffstat (limited to '')
-rw-r--r-- | test/interface/explicit.go | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/test/interface/explicit.go b/test/interface/explicit.go new file mode 100644 index 0000000..e18d684 --- /dev/null +++ b/test/interface/explicit.go @@ -0,0 +1,106 @@ +// errorcheck + +// Copyright 2009 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. + +// Verify compiler messages about erroneous static interface conversions. +// Does not compile. + +package main + +type T struct { + a int +} + +var t *T + +type X int + +func (x *X) M() {} + +type I interface { + M() +} + +var i I + +type I2 interface { + M() + N() +} + +var i2 I2 + +type E interface{} + +var e E + +func main() { + e = t // ok + t = e // ERROR "need explicit|need type assertion" + + // neither of these can work, + // because i has an extra method + // that t does not, so i cannot contain a t. + i = t // ERROR "incompatible|missing M method" + t = i // ERROR "incompatible|assignment$" + + i = i2 // ok + i2 = i // ERROR "incompatible|missing N method" + + i = I(i2) // ok + i2 = I2(i) // ERROR "invalid|missing N method|cannot convert" + + e = E(t) // ok + t = T(e) // ERROR "need explicit|need type assertion|incompatible|cannot convert" + + // cannot type-assert non-interfaces + f := 2.0 + _ = f.(int) // ERROR "non-interface type|only valid for interface types|not an interface" + +} + +type M interface { + M() +} + +var m M + +var _ = m.(int) // ERROR "impossible type assertion" + +type Int int + +func (Int) M(float64) {} + +var _ = m.(Int) // ERROR "impossible type assertion" + +var _ = m.(X) // ERROR "pointer receiver" + +var ii int +var jj Int + +var m1 M = ii // ERROR "incompatible|missing" +var m2 M = jj // ERROR "incompatible|wrong type for M method" + +var m3 = M(ii) // ERROR "invalid|missing|cannot convert" +var m4 = M(jj) // ERROR "invalid|wrong type for M method|cannot convert" + +type B1 interface { + _() // ERROR "methods must have a unique non-blank name" +} + +type B2 interface { + M() + _() // ERROR "methods must have a unique non-blank name" +} + +type T2 struct{} + +func (t *T2) M() {} +func (t *T2) _() {} + +// Already reported about the invalid blank interface method above; +// no need to report about not implementing it. +var b1 B1 = &T2{} +var b2 B2 = &T2{} |