Add brief descriptions of why one might implement
an Is or As method.
Fixes#33364.
Change-Id: I81a091bf564c654ddb9ef3997e780451a01efb7a
Reviewed-on: https://go-review.googlesource.com/c/go/+/191338
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Explain wrapping and how to use Is and As in the package doc.
Explain "chain" in Is and As.
Updates #33364.
Change-Id: Ic06362106dbd129e33dd47e63176ee5355492086
Reviewed-on: https://go-review.googlesource.com/c/go/+/188737
Reviewed-by: Rob Pike <r@golang.org>
The Wrapper type no longer exists.
Change-Id: I21051f26c6722a957295819f2f385f2bbd0db355
Reviewed-on: https://go-review.googlesource.com/c/go/+/177618
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
golang.org/cl/175260 fixed Is panics if target is uncomparable. It did
add an useless condition checking whether target is comparable. Just
remove that condition.
Change-Id: I0a317056479638d209b0a0cbc7010c153558c087
Reviewed-on: https://go-review.googlesource.com/c/go/+/176497
Reviewed-by: Joan Lopez de la Franca Beltran <joanjan14@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The Unwrap function performs a type assertion looking for the Wrapper
interface. The method of that interface is called Unwrap but the
interface itself is called Wrapper.
Change-Id: Ie3bf296f93b773d36015bcab2a0e6585d39783c7
GitHub-Last-Rev: 32b1a0c2f8bf8f3eaebf6de252571d82313e86e0
GitHub-Pull-Request: golang/go#31794
Reviewed-on: https://go-review.googlesource.com/c/go/+/174917
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Unwrap, Is and As are as defined in proposal
Issue #29934.
Also add Opaque for enforcing an error cannot
be unwrapped.
Change-Id: I4f3feaa42e3ee7477b588164ac622ba4d5e77cad
Reviewed-on: https://go-review.googlesource.com/c/163558
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
