It must be in a namespace, function, or class. In particular, it can't
be in another match_first, doing so immediately associates any impl
inside with two different match_first scopes, but we only want them
associated with one for prioritization.
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
When parsing a pattern, if we encounter something that isn't pattern
syntax, try parsing as an expression instead. We only need one-token
lookahead to distinguish pattern syntax from expression syntax.
Track a precedence group through pattern parsing so that we can allow
different kinds of expressions in a top-level pattern (such as the
operand of `let`) and in a nested pattern (such as a subpattern of a
tuple pattern or within grouping parens). For example, we do not allow
`case if ...`, and for now I've chosen to also not allow logical or
relational operators at the top level of a pattern, so `case 1 + 1` is
OK, but `case 1 == 1` and `case true and false` require parentheses.
This decision should be ratified or revisited by a design proposal.
Very basic check support is also provided, only sufficient to form an
`ExprPattern` instruction and nothing beyond that. For now, all pattern
matching against an `ExprPattern` fails with a TODO error. To support
that, I've switched from calling `BeginSubpattern` in the parent handler
of a pattern and `EndSubpatternAs*` in the pattern handler itself to
calling both functions in parent handlers, with `EndSubpattern`
converting an expression into an expression pattern where needed.
Depends on #6976.
Assisted-by: Gemini via Google Antigravity
Decouples associated constants from being special cased in let handlers.
Enforces associated constant grammar restrictions in parsing instead of
checking.
Closes#5411
Also renames variables of that type to match. A follow-up PR will rename
`Parse::StateStackEntry` to `Parse::State`. This is more consistent with
the naming of similar enums elsewhere in the toolchain, and with the
prevailing practice of using `state` rather than e.g. `entry` as the
name of a `StateStackEntry`.
See also discussion
[here](https://discord.com/channels/655572317891461132/963846118964350976/1326280585592700990)
These don't fully work in check and beyond yet, because they're not
added into lexical lookup, but already mostly do the right thing.
Per #3407, disallow namespace declarations anywhere other than at file
scope for now.
We don't treat statements starting with a packaging introducer keyword
(`package`, `library`, `import`) as declarations because they're
sufficiently unlikely to occur that the error recovery doesn't seem
important, and this avoids needing to disambiguate `package.` at the
start of an expression.
This is a primarily automated change:
- Search & replace for capitalization
-
`(CARBON_DIAGNOSTIC\((?:\n\s+)?\w+,(?:\n\s+)?\s\w+,(?:\n\s+)?\s")([A-Z])`
- `$1\L$2`
- Search & replace for period
-
`(CARBON_DIAGNOSTIC\((?:\n\s+)?\w+,(?:\n\s+)?\s\w+,(?:\n\s+)?\s"(?:[^)]|\n)+)\.("[,)])`
- `$1$2`
- Limited search & replace for `ERROR: ` -> `error: ` in streamed things
- Leaving a TODO for command_line because there's more cleanup that can
be done there
- Modify diagnostic_consumer.cpp
- ERROR -> error
- WARNING -> warning
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Move subtree sizes over to TreeAndSubtrees, using the different
structure to represent the additional parse work that occurs, as well as
making it clear which functions require the extra information. My intent
is to make it hard to use this by accident.
The subtree size is still tracked during Parse::Tree construction. I
think a lot of that can be cleaned up, although we use it during
placeholder assignment so it may take some work. I wanted to see what
people thought about this before taking action on such a change.
I'm using a 1m line source file generated by #4124 for testing. Command
is `time bazel-bin/toolchain/install/prefix_root/bin/carbon compile
--phase=check --dump-mem-usage ~/tmp/data.carbon`
At head, what I'm seeing is:
```
...
parse_tree_.node_impls_:
used_bytes: 61516116
reserved_bytes: 61516116
...
Total:
used_bytes: 447814230
reserved_bytes: 551663894
...
1.43s user 0.14s system 99% cpu 1.565 total
```
With `Tree::Verify` disabled completely, it looks like:
```
parse_tree_.node_impls_:
used_bytes: 41010744
reserved_bytes: 41010744
...
Total:
used_bytes: 427308858
reserved_bytes: 531158522
...
1.20s user 0.13s system 99% cpu 1.332 total
```
Re-enabling just the basic verification (what is now `Tree::Verify`),
I'm seeing maybe 0.05s slower, but that's within noise for my system. I
do see variability in my timing results, and overall I think this is a
0.2s +/- 0.1s improvement versus the earlier (always testing `Extract`
code) implementation. That's opt; debug builds will be unaffected,
because the same checking occurs as before.
Note, the subtree size is a third of the node representation, which is
why I'm showing the decrease in memory usage here.
Most of these are places where we failed to include a header file and
simply never got an error about this. The fix is to include the header
file.
Most other cases are functions that should have been marked `static` but
were not. Finding all of these was a main motivation for me enabling the
warning despite how much work it is.
One complicating factor was that we weren't including the `handle.h` for
all the state-based handler functions. While this isn't a tiny amount of
code, it is just declarations and doesn't add any extra dependencies. It
also lets us have the checking for which functions need to be `static`
and which don't. For the `parse` library I had to add the `handle.h`
header as well, I tried to match the design of it in `check`.
I have also had to work around a bug in the warning, but given the value
it seems to be providing, that seems reasonable. I've filed the bug
upstream: https://github.com/llvm/llvm-project/issues/94138
I also had to use some hacks to work around limitations of Bazel rules
that wrap `cc_library` rules and don't expose `copts`. I filed a bug for
`cc_proto_library` specifically:
~https://github.com/bazelbuild/bazel/issues/22610~https://github.com/bazelbuild/bazel/issues/4446
Adds `BindAlias` with a hybrid of `BindName` and `NameRef` semantics. I
think it's slightly closer to `BindName` because it introduces a name,
so I'm going more in that direction. This also matches the need for
`bind_name_id` with imports on enclosing scopes.
Note, only things that look like a name reference are being allowed on
the RHS of `alias`. This includes builtins that look like name
references, such as `bool`, but not ones that turn into values
underneath, such as `false`.
For now, we require the same introducer to be used each time a class is
declared, but see #3384.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Implement toolchain support for `returned var` and `return var`.
- Modeled `returned` in the parse tree as a `ReturnedSpecifier`
appearing after the `VariableIntroducer`.
- Modeled `return var` in the parse tree as a `ReturnVarSpecifier`
appearing after the `ReturnStatementStart`.
- Factored out the implementation of `return` statement and `returned
var` handling in check into a new `return.{h,cpp}`. The parse nodes
themselves are still handled in `handle_*.cpp`. This allows easy code
reuse between `return` and `returned var`.
A `let` declaration is represented by a `bind_name` node in SemIR:
```carbon-semir
%b: i32 = bind_name "b", %a
```
Because `Check` encounters the pattern before it sees the value, we
first create the `bind_name` node with an unset value and don't add it
to the block. Then, once we've seen and converted the initializer, we
update the `bind_name` to have the value and add it to the current
block, after the initializer code.
Continuing with #3070. Just a dir and file rename (mostly removing
prefixes, although for parse_tree_fuzzer and parse_tree_file_test I'm
dropping "tree" instead of "parse"). Everything in the parse dir should
be marked as a move.
oli-ej
Dana Jansens
Chandler Carruth
Richard Smith
Özgür
Geoff Romer
Elliott Kalt
Thomas Köppe
Jon Ross-Perkins
czapiga
josh11bandJon Ross-Perkins