The spec is not conclusive about whether a non-constant shift of
certain untyped constant left operands is valid when the shift
expression appears as an index in an index or slice expression,
or as a size in a `make` function call.
Despite identical spec rules in all these cases, cmd/compile accepts
make([]byte, 1.0 << s)
but pronounces an error for
a[1.0 << s]
(go/types accepts both).
This change clarifies the spec by explicitly stating that an
untyped constant left operand in a non-constant shift (1.0 in
the above examples) will be given type `int` in these contexts.
A separate issue #21693 addresses the cmd/compile bug.
Fixes#14844.
Change-Id: I4b52125e487a607fae377fcbed55463cdce9836c
Reviewed-on: https://go-review.googlesource.com/60230
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, cgo supports only macros which can be reduced to constants
or variables. The CL addresses remaining parts, macros which can be
represented as niladic functions.
The basic idea is simple:
1. make a thin wrapper function per macros.
2. replace macro expansions with function calls.
Fixes#10715Fixes#18720
Change-Id: I150b4fb48e9dc4cc34466ef6417c04ac93d4bc1a
Reviewed-on: https://go-review.googlesource.com/43970
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The last sentence in the section on slice expressions could be read
as if it might apply to strings. Changed the sentence a bit to
emphasize its applicability to slices only. See also the issue for
more background.
Fixes#19220.
Change-Id: I8551f34230e4ed93f951e7b871cc81f54a5874a9
Reviewed-on: https://go-review.googlesource.com/59890
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Throughout the spec we use the notion of a constant x being
representable by a value of type T. While intuitively clear,
at least for floating-point and complex constants types, the
concept was not well-defined. In the section on Conversions
there was an extra rule for floating-point types only and it
missed the case of floating-point values overflowing to an
infinity after rounding.
Since the concept is important to Go, and a compiler most
certainly will have a function to test "representability",
it seems warranted to define the term explicitly in the spec.
This change introduces a new entry "Representability" under
the section on "Properties of types and values", and defines
the term explicitly, together with examples.
The phrase used is "representable by" rather than "representable as"
because the former use is prevalent in the spec.
Additionally, it clarifies that a floating-point constant
that overflows to an infinity after rounding is never
representable by a value of a floating-point type, even though
infinities are valid values of IEEE floating point types.
This is required because there are not infinite value constants
in the language (like there is also no -0.0) and representability
also matters for constant conversions. This is not a language
change, and type-checkers have been following this rule before.
The change also introduces links throughout the spec to the new
section as appropriate and removes duplicate text and examples
elsewhere (Constants and Conversions sections), leading to
simplifications in the relevant paragraphs.
Fixes#15389.
Change-Id: I8be0e071552df0f18998ef4c5ef521f64ffe8c44
Reviewed-on: https://go-review.googlesource.com/57530
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The enumeration of numeric types missed the complex types.
Clarify by removing the explicit enumeration and referring
to numeric types instead.
Fixes#21579.
Change-Id: If36c2421f8501eeec82a07f442ac2e16a35927ba
Reviewed-on: https://go-review.googlesource.com/58491
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The old wording seemed to imply that nil is a kind of type.
Slightly reworded for clarity.
Fixes#21580.
Change-Id: I29898bf0125a10cb8dbb5c7e63ec5399ebc590ca
Reviewed-on: https://go-review.googlesource.com/58490
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Rob Pike <r@golang.org>
Pre-emptive. Go 1.9 is expected to be released in August.
Change-Id: I0f58c012c4110bf490022dc2c1d69c0988d73bfa
Reviewed-on: https://go-review.googlesource.com/52351
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The old comment for the example
type PtrMutex *Mutex
talked about the method set of the base type of PtrMutex.
It's more direct and clearer to talk about the underlying
type of PtrMutex for this specific example.
Also removed link inside pre-formatted region of text.
Fixes#20900.
Change-Id: Ie37340e53670e34ebe13e780ba8ccb1bba67795c
Reviewed-on: https://go-review.googlesource.com/55070
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Some editors can filter the autocompletion suggestions based on
whether the code will compile once autocompleted. Explain this
feature with better wording.
Change-Id: I29e4b0396878f18c79208915402c0a209a813b04
Reviewed-on: https://go-review.googlesource.com/53355
Reviewed-by: Florin Patan <florinpatan@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
/blog redirects to blog.golang.org (currently blocked in China)
unless there is a local checkout of golang.org/x/blog, which is
not possible on App Engine Classic.
Change-Id: Ia695e663c9bebcc6c3bedea324c630299eaad4dc
Reviewed-on: https://go-review.googlesource.com/53051
Reviewed-by: Chris Broadfoot <cbro@golang.org>
In the case where requests are coming from mainland China, hide
links to locations that are blocked and functionality that is
not permitted.
Additionally, some very small cleanup of the JS.
This change requires https://go-review.googlesource.com/c/52873
Change-Id: I7fc68748e629dbe5b966d6bf117e7f7b546966eb
Reviewed-on: https://go-review.googlesource.com/52872
Reviewed-by: Chris Broadfoot <cbro@golang.org>
So the users can recognize their option by their editor's name.
Fixes#20398.
Change-Id: Id314d4dbe26f40231a479b179620d7e66512b506
Reviewed-on: https://go-review.googlesource.com/51114
Reviewed-by: Chris Broadfoot <cbro@golang.org>
The Go ecosystem provides many tools to make Go
development more productive and seamless. Document
the availability of the editor plugins and IDEs,
add an overview of feature support and screencasts.
Updates #20398.
Updates #20402.
Updates #20399.
Updates #20401.
Updates #20569.
Change-Id: I0c6cb48eb4e3848807aaad78390493e14f097916
Reviewed-on: https://go-review.googlesource.com/45772
Reviewed-by: Steve Francia <spf@golang.org>
Per note at top of doc, we don't use fixed-width spaces
in fixed-width phrases like "go doc".
Also ASN.1 NULL is not code so it's not <code> at all.
Change-Id: I791e4e6030b8b8d42f4621d2f4bf32fef93cf343
Reviewed-on: https://go-review.googlesource.com/47693
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Neither the Gerrit UI nor its docs use the term CL or changelist.
Change-Id: Ic19fddc660ec4f008f10fd207e4ac6349431ff5d
Reviewed-on: https://go-review.googlesource.com/48595
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
To-be-released NetBSD 7.1.1 reportedly fixes the kernel panic that was
affecting our builders and is being released because of Go's warning.
So, soften our warning.
7.1.1 might work, but I can't get a builder up and running to verify
yet as it appears that Anita either doesn't support it yet, or the
NetBSD CDN doesn't have the files yet.
Change-Id: Ifaafc566879a6afdf1174e545ad10e240da427e8
Reviewed-on: https://go-review.googlesource.com/47970
Reviewed-by: Ian Lance Taylor <iant@golang.org>
A lot of code that uses runtime.Callers makes assumptions about the
result that are not true today under gccgo and will not be true in the
future in gc. This adds a section to the release notes discussing how
to correctly use runtime.Callers.
Change-Id: I96b7c7ef183cee2061442fc3501fceceefa54c09
Reviewed-on: https://go-review.googlesource.com/47691
Reviewed-by: Russ Cox <rsc@golang.org>
FreeBSD 9.3.
Add Linux arm64. (required second line)
Clarify glibc requirement now that we have second line in notes.
OS X to macOS
Updates #20850
Change-Id: I684d464ed32a072081726b7c805a346c22c42f97
Reviewed-on: https://go-review.googlesource.com/47252
Reviewed-by: Ian Lance Taylor <iant@golang.org>
