tree 9f7e5994fb2f627b60fc038fcf7b1fee8a063020
parent 85bb37444ad2b5447a3681fadf34ccc45330bad8
author Rob Findley <rfindley@anthropic.com> 1776025083 +0000
committer Gopher Robot <gobot@golang.org> 1776704282 -0700

internal/astutil: preserve [...] composite literals in PurgeFuncBodies

PurgeFuncBodies deletes the contents of every outermost {...} region
except struct/interface type bodies. That includes the bodies of
[...]T composite literals, whose element count is part of the type:
purging [...]int{1,2,3} to [...]int{} changes the type from [3]int to
[0]int, and similarly affects constant values such as
len([...]int{1,2,3}).

This was harmless for the existing callers (typerefs and unimported
completion both ignore composite-literal elements anyway), but it
prevents using the purged source as a type-shape fingerprint for
caching.

Add a single ellipsis flag, set when "...]" is seen and consumed by
the next non-struct/interface "{", to preserve [...] literal bodies
verbatim. All other composite literals are still purged, since their
contents don't affect the type of the enclosing declaration.

Add a table-driven test for the cases that motivated the change, and
update the property test's reference oracle to match.

Updates golang/go#69523

Change-Id: I52b3d41848d5c674685cd90f2be57e94dd5e0bfc
Reviewed-on: https://go-review.googlesource.com/c/tools/+/766140
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Madeline Kalil <mkalil@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Robert Findley <rfindley@golang.org>