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| author | Robert Griesemer <gri@golang.org> | 2023-06-26 13:52:37 -0700 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2023-06-26 21:06:37 +0000 |
| commit | 1dbbafc70fd3e2c284469ab3e0936c1bb56129f6 (patch) | |
| tree | 16d596f655f8392004afdb8742f9933362b5c97f | |
| parent | 7cc07405962d804f0386baad100b1b5084dda4c0 (diff) | |
| download | go-1dbbafc70fd3e2c284469ab3e0936c1bb56129f6.tar.gz go-1dbbafc70fd3e2c284469ab3e0936c1bb56129f6.zip | |
go/types, types2: replace TODO with clarifying comment
This resolves an open question.
No non-comment code changes.
Change-Id: Idc92794090b2dde694394d1fcd916f6ea61f03e7
Reviewed-on: https://go-review.googlesource.com/c/go/+/506395
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
| -rw-r--r-- | src/cmd/compile/internal/types2/unify.go | 7 | ||||
| -rw-r--r-- | src/go/types/unify.go | 7 |
2 files changed, 10 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/types2/unify.go b/src/cmd/compile/internal/types2/unify.go index 0f1423ff98..94830e94f7 100644 --- a/src/cmd/compile/internal/types2/unify.go +++ b/src/cmd/compile/internal/types2/unify.go @@ -410,8 +410,11 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) { // recorded an underlying type (go.dev/issue/43056). // Either both types are interfaces, or neither type is. // If both are interfaces, they have the same methods. - // TODO(gri) We probably can do this only for inexact - // unification. Need to find a failure case. + // + // Note: Changing the recorded type for a type parameter to + // a defined type is only ok when unification is inexact. + // But in exact unification, if we have a match, x and y must + // be identical, so changing the recorded type for x is a no-op. if yn { u.set(px, y) } diff --git a/src/go/types/unify.go b/src/go/types/unify.go index 1b1d875dad..bef851f423 100644 --- a/src/go/types/unify.go +++ b/src/go/types/unify.go @@ -412,8 +412,11 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) { // recorded an underlying type (go.dev/issue/43056). // Either both types are interfaces, or neither type is. // If both are interfaces, they have the same methods. - // TODO(gri) We probably can do this only for inexact - // unification. Need to find a failure case. + // + // Note: Changing the recorded type for a type parameter to + // a defined type is only ok when unification is inexact. + // But in exact unification, if we have a match, x and y must + // be identical, so changing the recorded type for x is a no-op. if yn { u.set(px, y) } |