diff options
| -rw-r--r-- | src/cmd/compile/internal/noder/transform.go | 15 | ||||
| -rw-r--r-- | test/typeparam/issue48453.go | 21 |
2 files changed, 33 insertions, 3 deletions
diff --git a/src/cmd/compile/internal/noder/transform.go b/src/cmd/compile/internal/noder/transform.go index a117e310ea..3e5cfacb97 100644 --- a/src/cmd/compile/internal/noder/transform.go +++ b/src/cmd/compile/internal/noder/transform.go @@ -431,9 +431,18 @@ func Assignop(src, dst *types.Type) (ir.Op, string) { return ir.OXXX, "" } - // 1. src type is identical to dst. - if types.IdenticalStrict(src, dst) { - return ir.OCONVNOP, "" + // 1. src type is identical to dst (taking shapes into account) + if types.Identical(src, dst) { + // We already know from assignconvfn above that IdenticalStrict(src, + // dst) is false, so the types are not exactly the same and one of + // src or dst is a shape. If dst is an interface (which means src is + // an interface too), we need a real OCONVIFACE op; otherwise we need a + // OCONVNOP. See issue #48453. + if dst.IsInterface() { + return ir.OCONVIFACE, "" + } else { + return ir.OCONVNOP, "" + } } return typecheck.Assignop1(src, dst) } diff --git a/test/typeparam/issue48453.go b/test/typeparam/issue48453.go new file mode 100644 index 0000000000..0f751d38ed --- /dev/null +++ b/test/typeparam/issue48453.go @@ -0,0 +1,21 @@ +// run -gcflags=-G=3 + +// 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. + +package main + +//go:noinline +func CopyMap[M interface{ ~map[K]V }, K comparable, V any](m M) M { + out := make(M, len(m)) + for k, v := range m { + out[k] = v + } + return out +} + +func main() { + var m map[*string]int + CopyMap(m) +} |