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5 commits

Author SHA1 Message Date
Robert Griesemer
1abc6b0204 go/types, types2: permit type cycles through type parameter lists
Issue #49439 was about a deadlock during type inference inside
a type parameter list of a recursive constraint. As a remedy
we disallowed recursive type parameter lists.

In the meantime we have removed support for type inference for
type arguments to generic types; the Go 1.18 generic release
didn't support it.

As a consequence, the fix for #49439, CL 361922, is probably
not needed anymore: cycles through type parameter lists are ok.

Fixes #68162.
For #49439.

Change-Id: Ie9deb3274914d428e8e45071cee5e68abf8afe9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/711420
Commit-Queue: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Mark Freeman <markfreeman@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Bypass: Robert Griesemer <gri@google.com>
2025-10-13 14:27:13 -07:00
Robert Griesemer
e22af33b48 go/types, types2: more concise error messages for cycle errors
If a cycle has length 1, don't enumerate the single cycle entry;
instead just mention "refers to itself". For instance, for an
invalid recursive type T we now report:

	invalid recursive type: T refers to itself

instead of:

	invalid recursive type T
		T refers to
		T

Adjust tests to check for the different error messages.

Change-Id: I5bd46f62fac0cf167f0d0c9a55f952981d294ff4
Reviewed-on: https://go-review.googlesource.com/c/go/+/436295
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Robert Griesemer <gri@google.com>
2022-09-29 14:21:33 +00:00
Matthew Dempsky
e24977d231 all: avoid use of cmd/compile -G flag in tests
The next CL will remove the -G flag, effectively hard-coding it to its
current default (-G=3).

Change-Id: Ib4743b529206928f9f1cca9fdb19989728327831
Reviewed-on: https://go-review.googlesource.com/c/go/+/388534
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
2022-03-01 19:45:34 +00:00
Robert Griesemer
cc14fcac2b cmd/compile/internal/types2: disallow type cycles through type parameter lists
If we reach a generic type that is part of a cycle
and we are in a type parameter list, we have a cycle
through a type parameter list, which is invalid.

Fixes #49439.

Change-Id: Ia6cf97e1748ca0c0e61c02841202050091365b0b
Reviewed-on: https://go-review.googlesource.com/c/go/+/361922
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2021-11-10 00:56:09 +00:00
Matthew Dempsky
fb84e99eb7 test: add compiler regress tests for #46461
gri@ reports that types2 now correctly handles when type parameters
recursively refer back to the parameterized type, so we might as well
add tests to exercise that. Unified IR also correctly handles
importing and exporting these types, but -G=3 currently does not.

Updates #46461.

Change-Id: I272102aa08c40c980b9aeeca9f834291dfbbcc3e
Reviewed-on: https://go-review.googlesource.com/c/go/+/348738
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2021-09-09 19:37:25 +00:00