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go/test/interface/explicit.go
Alberto Donizetti 1737aef270 cmd/compile: more error position tests for the typechecker
This change adds line position tests for several yyerror calls in the
typechecker that are currently not tested in any way.

Untested yyerror calls were found by replacing them with

  yerrorl(src.NoXPos, ...)

(thus destroying position information in the error), and then running
the test suite. No failures means no test coverage for the relevant
yyerror call.

For #19683

Change-Id: Iedb3d2f02141b332e9bfa76dbf5ae930ad2fddc3
Reviewed-on: https://go-review.googlesource.com/41477
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-04-24 12:37:49 +00:00

106 lines
1.9 KiB
Go

// 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"
e = E(t) // ok
t = T(e) // ERROR "need explicit|need type assertion|incompatible"
// cannot type-assert non-interfaces
f := 2.0
_ = f.(int) // ERROR "non-interface type"
}
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"
var m4 = M(jj) // ERROR "invalid|wrong type for M method"
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) _() {}
// Check that nothing satisfies an interface with blank methods.
var b1 B1 = &T2{} // ERROR "incompatible|missing _ method"
var b2 B2 = &T2{} // ERROR "incompatible|missing _ method"