cmd/compile/internal/types2: implement Identical for *Union types
This is a clean port of CL 349413 from go/types to types2.
Change-Id: I18bad5e29b1e719b30a73fb2aa32fe252538496e
Reviewed-on: https://go-review.googlesource.com/c/go/+/349992
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
diff --git a/src/cmd/compile/internal/types2/api_test.go b/src/cmd/compile/internal/types2/api_test.go
index 3ec0d78..5a20738 100644
--- a/src/cmd/compile/internal/types2/api_test.go
+++ b/src/cmd/compile/internal/types2/api_test.go
@@ -1645,6 +1645,48 @@
}
}
+func TestIdenticalUnions(t *testing.T) {
+ tname := NewTypeName(nopos, nil, "myInt", nil)
+ myInt := NewNamed(tname, Typ[Int], nil)
+ tmap := map[string]*Term{
+ "int": NewTerm(false, Typ[Int]),
+ "~int": NewTerm(true, Typ[Int]),
+ "string": NewTerm(false, Typ[String]),
+ "~string": NewTerm(true, Typ[String]),
+ "myInt": NewTerm(false, myInt),
+ }
+ makeUnion := func(s string) *Union {
+ parts := strings.Split(s, "|")
+ var terms []*Term
+ for _, p := range parts {
+ term := tmap[p]
+ if term == nil {
+ t.Fatalf("missing term %q", p)
+ }
+ terms = append(terms, term)
+ }
+ return NewUnion(terms)
+ }
+ for _, test := range []struct {
+ x, y string
+ want bool
+ }{
+ // These tests are just sanity checks. The tests for type sets and
+ // interfaces provide much more test coverage.
+ {"int|~int", "~int", true},
+ {"myInt|~int", "~int", true},
+ {"int|string", "string|int", true},
+ {"int|int|string", "string|int", true},
+ {"myInt|string", "int|string", false},
+ } {
+ x := makeUnion(test.x)
+ y := makeUnion(test.y)
+ if got := Identical(x, y); got != test.want {
+ t.Errorf("Identical(%v, %v) = %t", test.x, test.y, got)
+ }
+ }
+}
+
func TestIssue15305(t *testing.T) {
const src = "package p; func f() int16; var _ = f(undef)"
f, err := parseSrc("issue15305.go", src)
diff --git a/src/cmd/compile/internal/types2/predicates.go b/src/cmd/compile/internal/types2/predicates.go
index aa797fc..74ad3da 100644
--- a/src/cmd/compile/internal/types2/predicates.go
+++ b/src/cmd/compile/internal/types2/predicates.go
@@ -225,6 +225,13 @@
identical(x.results, y.results, cmpTags, p)
}
+ case *Union:
+ if y, _ := y.(*Union); y != nil {
+ xset := computeUnionTypeSet(nil, nopos, x)
+ yset := computeUnionTypeSet(nil, nopos, y)
+ return xset.terms.equal(yset.terms)
+ }
+
case *Interface:
// Two interface types are identical if they describe the same type sets.
// With the existing implementation restriction, this simplifies to:
