cmd/compile: support reading union type for compiler backend in unified IR

Fixes #52124

Change-Id: I5749822d41d8e51f476bceb277b1d2cf7350dcc3
Reviewed-on: https://go-review.googlesource.com/c/go/+/397874
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index 01e795183d853961bbb6d4d62fa66954224481dd..71efac80aa7223a7f12dd342855a3873943be102 100644 (file)
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -442,9 +442,21 @@ func (r *reader) doTyp() *types.Type {
                return r.structType()
        case pkgbits.TypeInterface:
                return r.interfaceType()
+       case pkgbits.TypeUnion:
+               return r.unionType()
        }
 }
 
+func (r *reader) unionType() *types.Type {
+       terms := make([]*types.Type, r.Len())
+       tildes := make([]bool, len(terms))
+       for i := range terms {
+               tildes[i] = r.Bool()
+               terms[i] = r.typ()
+       }
+       return types.NewUnion(terms, tildes)
+}
+
 func (r *reader) interfaceType() *types.Type {
        tpkg := types.LocalPkg // TODO(mdempsky): Remove after iexport is gone.
 

diff --git a/test/typeparam/issue52124.go b/test/typeparam/issue52124.go
new file mode 100644 (file)
index 0000000..56318d5
--- /dev/null
+++ b/test/typeparam/issue52124.go
@@ -0,0 +1,9 @@
+// compile
+
+// Copyright 2022 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 p
+
+type I interface{ any | int }