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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
commit | 43a123c1ae6613b3efeed291fa552ecd909d3acf (patch) | |
tree | fd92518b7024bc74031f78a1cf9e454b65e73665 /test/typeparam/stringer.go | |
parent | Initial commit. (diff) | |
download | golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.tar.xz golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.zip |
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'test/typeparam/stringer.go')
-rw-r--r-- | test/typeparam/stringer.go | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/test/typeparam/stringer.go b/test/typeparam/stringer.go new file mode 100644 index 0000000..0892cd8 --- /dev/null +++ b/test/typeparam/stringer.go @@ -0,0 +1,88 @@ +// run + +// Copyright 2021 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. + +// Test method calls on type parameters + +package main + +import ( + "fmt" + "reflect" + "strconv" +) + +// Simple constraint +type Stringer interface { + String() string +} + +func stringify[T Stringer](s []T) (ret []string) { + for _, v := range s { + ret = append(ret, v.String()) + } + return ret +} + +type myint int + +func (i myint) String() string { + return strconv.Itoa(int(i)) +} + +// Constraint with an embedded interface, but still only requires String() +type Stringer2 interface { + CanBeStringer2() int + SubStringer2 +} + +type SubStringer2 interface { + CanBeSubStringer2() int + String() string +} + +func stringify2[T Stringer2](s []T) (ret []string) { + for _, v := range s { + ret = append(ret, v.String()) + } + return ret +} + +func (myint) CanBeStringer2() int { + return 0 +} + +func (myint) CanBeSubStringer2() int { + return 0 +} + +// Test use of method values that are not called +func stringify3[T Stringer](s []T) (ret []string) { + for _, v := range s { + f := v.String + ret = append(ret, f()) + } + return ret +} + +func main() { + x := []myint{myint(1), myint(2), myint(3)} + + got := stringify(x) + want := []string{"1", "2", "3"} + if !reflect.DeepEqual(got, want) { + panic(fmt.Sprintf("got %s, want %s", got, want)) + } + + got = stringify2(x) + if !reflect.DeepEqual(got, want) { + panic(fmt.Sprintf("got %s, want %s", got, want)) + } + + got = stringify3(x) + if !reflect.DeepEqual(got, want) { + panic(fmt.Sprintf("got %s, want %s", got, want)) + } +} |