Also add a default for `EqWith.NotEqual`.
Switch advent examples to use these named constraints, and also go
through all the other TODOs in the advent examples and fix the ones that
are trivially fixable now.
As discussed in the 2026-06-14 toolchain open meeting, `Range`
is a better fit for the prelude than as a general library in
`Core`. This PR moves `Range` into the prelude, and updates
the build infrastructure and various tests to reflect that
change.
Implement the toolchain side of proposal #7254, removing the `:!`
binding
syntax for generic and template parameters in favor of the keywords
`generic`,
`template`, and `runtime` plus contextual defaults for phase.
For valid programs this is semantics-preserving: each binding resolves
to the
same phase, and produces the same SemIR, as it did under `:!`/`:`. The
parser
derives a binding's phase from its syntactic context plus any explicit
phase
keyword; new diagnostics and error recovery for misused keywords are
described
below.
Implementation details for each component:
- Lexer: remove the `:!` (`ColonExclaim`) token, move its virtual
parse-node
budget onto `:`, and add the `generic` and `runtime` keywords.
- Parser: thread a `BindingContext` (`ExplicitParam`, `DeducedParam`, or
`CompileTimeEntityParam`) from declaration introducers down through
parameter
lists to each binding pattern, using a one-token lookahead to
distinguish a
name-qualifier parameter list from a declaration's own final list.
Parameters
of a compile-time entity (`class`, `interface`, `constraint`, `choice`,
`alias`, `export`, `namespace`) and deduced `[]` parameters default to
checked
generic; explicit function parameters and local bindings default to
runtime.
`HandleBindingPattern` resolves the phase from that context plus the
keyword: a
`generic` keyword needs no node of its own (the phase is carried by the
binding's node kind), while a `runtime` keyword is preserved as a
`RuntimeBindingName` node so `check` can name it in a diagnostic. A
phase
keyword that is merely redundant with the contextual default is
diagnosed
here, without invalidating the parse tree.
- Check: a phase keyword that is invalid for its context (for example
`runtime`
on a checked-generic parameter) is diagnosed here, and recovers by
building an
error binding that still introduces the name so that later uses of it do
not
produce cascading errors.
The removed `:!` syntax is now rejected as an ordinary parse error.
The `form`/`:?`/`->?` ("extended types") portion of proposal #7254 is
left for a
separate change.
Assisted-by: Claude Code
Implements proposal #7016: `self` moves from the deduced implicit list
(`fn F[self: Self]()`) to the front of the explicit list. Its type may
be written explicitly (`fn F(self: Self)`) or omitted, in which case it
defaults to `Self` (`fn F(self)`, `fn F(ref self)`); `self` in the
implicit list is rejected.
Throughout checking, `self` is modeled as the first explicit parameter.
Because a method is just a function whose first parameter is `self`, it
can also be called as an ordinary function with the receiver passed
explicitly (`Type.M(obj, ...)`), not only as `obj.M(...)`. A new
`SemIR::CallArgParamPatterns` helper chooses the parameters matched
against the explicit arguments, excluding a leading `self` only when it
is supplied as a method-call receiver; arity checking, conversion, and
generic deduction use it. The resulting SemIR and lowering are
unchanged: `self` is still `call_param0`, and witnesses, thunks, and
vtables are unaffected.
An omitted `self` type is parsed as a `SelfBindingPattern` node with no
type expression; checking synthesizes the `Self` type so it behaves
exactly like `self: Self`. However, the exact spelling used must match
between a forward declaration and a definition, following #3763's rules
around declaration matching.
Generated functions, thunks, and C++ interop import/export build `self`
as the first explicit parameter, and the `self`-type override (e.g.
Derived->Base for a virtual override) applies to the explicit `self`.
Placement is validated by new diagnostics: `SelfInImplicitParamList`,
`SelfNotFirstParam`, and `SelfOutsideParamList`. The benchmark source
generator and the documentation adopt the `(self)` shorthand; the
prelude, the examples, and the test data are migrated in the following
commits.
Assisted-by: Claude Code with Claude Opus 4.7
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
We exposed `Core.IntLiteral()`, `Core.FloatLiteral()`,
`Core.CharLiteral()`, and `Core.Bool()` as functions as a workaround,
because we had no way to provide the type names without parentheses that
the design requests. But now we can do so, by using an alias. Switch all
of these over from being functions to simply being names of the
corresponding types.
Assisted-by: Gemini via Antigravity
Not sure how these got missed when moving other things to `uv`, but this
should clean them up.
The bump to Python 3.12 is so that we can use `@override` with the
simple import from `typing`. This is needed by the newest versions of
`ty` to do type checking. Added the relevant `@override` annotations.
Assisted-by: Antigravity with Gemini
This also switches to a more Bazel-based install layout, skipping the
FHS-based synthetic layout. The FHS-based layout is still reconstructed
explicitly when building an installable tar-ball.
The biggest change is to configure the just-built install as a Bazel
toolchain, including allowing it to build its own runtime libraries as
native Bazel libraries. This removes the need for a monolithic runtimes
build, all of that code logic is removed.
This should also pave the way to using the just-built toolchain for
doing a full 3-stage bootstrap. Building the 2nd stage is included here
as it was a particularly effective way to test that the Bazel
integration was fully working. Adding a 3rd-stage check for stability is
future work, but should be pretty easy.
There is a down-side: this uses the busybox to do the runtimes
compilation, which means they will be re-built after ~any change to
Carbon. However, the integration with Bazel should largely pay for this,
and we can continue to factor the tests away from depending on built
runtimes in most cases.
Now that we're building and testing the runtimes more directly, this
surfaced a problem with the layout of runtimes on macOS that is fixed
here. All of the Darwin OSes use a custom layout for their resource
directory compared to other targets. We now model this in both the C++
built runtimes and the Bazel built runtimes.
Assisted-by: Gemini via Antigravity
When a `var` is not explicitly given an initializer, initialize it in
one of two ways:
* If its type implements the new interface `Core.Default`, call
`Core.Default.Op` to initialize it.
* Otherwise, if its type implements `UnformedInit`, leave it in an
unformed state. For now, this is always an uninitialized state, but that
will change in the future.
* If neither of those apply, the `var` declaration is ill-formed.
This is a step towards implementing leads decision #6739 and proposals
#257 and #5913.
Assisted-by: Gemini 3.1 Pro via Antigravity
---------
Co-authored-by: Geoff Romer <gromer@google.com>
I wasn't sure I'd be able to really test this code path, but then
I remembered that Bazel has a whole platform for running Bazel from
within an integration test, and it turns out to work brilliantly. It
even lets us point the child Bazel invocations to the just-built
toolchain.
This should both give us confidence that we don't accidentally hit
a Bazel incompatibility with the example project, and it should ensure
that if something about the installed toolchain would stop being
compatible with building via Bazel we'll catch it early.
The tests are integration tests and so a bit slow: 15s or so. But
`//examples/...` is already pretty expensive and no other testing
patterns are impacted.
This let's you point Bazel at an installed toolchain or download one of
our release archives. When you do, it will configure itself as a C++
Bazel toolchain. This toolchain works reasonably well, but doesn't cache
the C++ runtimes, and so linking is inefficient. The next step will be
to pivot the runtimes from the implicitly on-demand (which can't cache
when using a sandboxed build system like Bazel) to _explicit_ on-demand
runtimes directly with Bazel support.
I've included an example Bazel project that uses this and provides a
bunch of documentation and an example script that should let folks try
this out easily.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: David Blaikie <dblaikie@gmail.com>
We can now cast directly from `T*` to `U*`; stop going via `void*`. Also
remove the conversion impl from `void*` as it's now subsumed by the
general impl.
Mostly generated by Gemini; TODO annotations added for cases where we
should support a better way of doing various parts of this.
Assisted-by: Gemini 3 Pro
---------
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
I've had these kicking around for a year but never got around to pushing
them. They seem to cover a few things that previous examples didn't, so
I think we may as well include them.
---------
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Support an implicit conversion from `T*` to `Cpp.void*` and to `const
Cpp.void*`, and an `unsafe as` conversion in the opposite direction.
In order to support C++ calls taking and returning `void*` (which get
mapped to Carbon `Optional(Cpp.void*)`, also support conversions from
`Optional(T)` to `Optional(U)` if there's a conversion from `T` to `U`.
Fix a bug in `OptionalStorage` for `T*` where its `HasValue` was exactly
backwards.
This enables on-demand building of runtimes by default, and enables
their header files for all of the Clang invocations. This also switches
the default flags to use the LLVM-provided runtimes (compiler-rt,
libunwind, and libcxx).
This also switches even `llvm_symlinks_test` to use the Bazel prebuilt
runtimes, which requires having a way to pass a Carbon flag even when
invoking the busybox as `clang` or `clang++`. This uses the pattern that
has worked for other Clang wrappers of spelling flags:
`-X<tool-name>=--flag=value`
Last but not least, this updates the Carbon Bazel rules to use our
installed and the Bazel prebuilt runtimes. With that, we make the C++
interop hello-world be enabled by default as this should pass reliably
on both Linux and macOS now.
* Use generics in more places.
* Use `ref` in more places.
* Use `for` in more places.
* Use a little bit of C++ interop.
* Use an adapter for the `char`-or-EOF result of reading a char instead
of pure `i32`, and use char literals where possible.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
We already did this translation in the other direction, but we had no
mapping from `Optional(T)` to anything, so round-tripping a nullable
pointer from C++ through Carbon and back to C++ was previously rejected.
Don't attempt to defer overload resolution by creating a
`CppOverloadSet`; this was incorrect as we weren't saving the complete
clang::OverloadCandidateSet, resulting in template candidates not being
found. Moreover, saving the overload candidate set would be expensive,
as the representation is surprisingly large, and is unnecessary since
we're about to build a call.
In passing, improve the diagnostics for overload resolution failure to
use Clang's operator overload resolution messages rather than its call
overload resolution messages.
This fixes calls to templated operator overloads, which is the final
piece needed for us to successfully compile an iostream-based "Hello
world" program.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Every test that used `addr` before #6283 should be using `ref` after
this PR. In most cases that was done in #6283, but this PR transitions a
few that I missed in that first pass. In addition, #6283 cloned the old
`addr` tests from `foo.carbon` to `foo_addr.carbon` in order to maintain
test coverage during the transition; this PR removes those cloned tests.
Most inputs are matched against the current regex. An input that starts
and ends with `/` sets a new regex instead. EOF terminates the program.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Based on #5920.
Added commented out better examples and clarified what is missing to
support them.
Added `tags` support to `carbon_binary` (based on #5967) to set the
`BUILD` rule to manual until we can find `cstdio` in macos.
```shell
$ bazel run examples/interop/cpp:hello_world
...
Hello world!
```
In line with the proposal in #4682, this changes the array syntax to be
array(T, N). `array` is a builtin keyword which must be followed by
parens containing two expressions and a separating comma.
The array type expression is still fully builtin, it does not forward to
a Core.Array library type yet. It merely adds the `ArrayType`
instruction, as was done with the previous syntax.
Followup work will change the instruction to reference to Core.Array,
once the library type exists and can be used directly.
---------
Co-authored-by: zygoloid <richard@metafoo.co.uk>
A collection of additional Carbon examples demonstrating current
language capabilities and some limitations of the current state of the
toolchain.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
In order to support these examples, this adds two new builtins to the
toolchain: `print.char` and `read.char`, which map to the libc functions
`putchar` and `getchar`.
Instead of treating `Core.Int` as the toolchain's builtin `IntType`,
model it as a class that adapts the builtin type. This aligns us better
with the intended language model, gives an associated library for
`impl`s involving `Core.Int` to live within, and opens the door adding
member functions to `Core.Int` if we decide that is desirable.
Remarkably it also seems to make the formatted SemIR a little smaller,
because a call to a generic class generates less IR than a call to a
function.
When an `IntLiteral` appears as an operand of an `if` expression,
convert it to `i32` for now, so that we don't reject things like `if
cond then 1 else 2` due to having a non-constant value of type
`IntLiteral`.
For tuple indexing expressions such as `(a, b).0`, convert the index to
type `IntLiteral`, not to type `i32`. This isn't strictly necessary to
do in this PR, but avoids the need to provide an `IntLiteral` -> `i32`
implicit conversion for `no_prelude` tests using this syntax.
We'd been discussing that explorer remains necessary for print, and I
was wondering if this kind of approach would be okay (we _probably_ want
this to work, based on #2110, albeit with more overloads -- but I don't
think there's a good way to support overloads at the moment).
```
╚╡../bazel-bin/examples/sieve
2
3
5
7
11
13
17
19
23
29
31
37
41
43
...
```
Note, I assume this doesn't affect all the TODOs (like for i32.carbon),
but does cut some things down (and requires updating some tests that
have prelude name conflicts, but I think they were intended to be
updated this way).
The driver now looks for all files under core/prelude/ and considers
them all to be part of the prelude. The driver also now only processes
the prelude in `--phase=check` and later, when it would actually be
imported.
With that done, add a simple `carbon_binary` build rule and use it to
build the example in `//examples`. This should cause the example to be
built as part of our continuous integration.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Move completeness check to the point where the function is defined or
first called. This means we also defer deciding whether the function has
a return slot until that point. Instead of storing a return slot per
function, store the location of the return storage, which may or may not
be used, and compute and store a separate flag saying whether to use it
at the point of first use or definition.
This is the final piece in supporting simple `Make` functions in classes
as a replacement for constructors.
Split apart the interfaces into separate libraries by theme. We don't
yet have a way to re-export them, so for now change importers to use the
fine-grained names.
This is almost certainly not how we'll want these to be organized, and
if the examples/ directory is kept it should have BUILD files. But this
at least lets me park these files somewhere that's more global than my
own checkout.
Richard Smith
Lucile Rose Nihlen
Chandler Carruth
Jon Ross-Perkins
Boaz Brickner
Dana Jansensandzygoloid