Updates the pattern matching code to support unspecified default values.
Adds logic to decl and def merge code to diagnose mismatches in defaults
if specified in both places, or if let entirely unspecified.
Per https://github.com/carbon-language/carbon-lang/pull/7521.
Adds a virtual node to `DefaultValuePattern` to end the
`ExprRegionForPattern` before checking the expression
for the default value.
When checking the default value expression, the context
was still configured to interpret expressions as patterns,
which caused some corruption of state with tuple-pattern
subpatterns.
Corrects an assertion failure I found while working on
feedback from #7665.
Adds check functionality to transform the parse node to SemIR. Only
supported for single declarations of functions, re-declaration and
imports to come in a subsequent PR.
Per #7521.
Adds parsing support only for default value expressions in pattern
lists, including leaving the default value unspecified with an
underscore `_`.
Per #7521.
Instead of maintaining a stack of pending subpatterns which might or
might not contain expressions, we mark non-nesting regions during
pattern handling that might contain an expression. The implementation
remains largely the same; the difference is that callers are expected to
end a pending expression region as soon as possible, rather than wait
for the end of the subpattern. This makes it possible to emit
non-pattern insts during pattern handling, without the risk that they
will get caught in a pending expression region further up the stack.
This adds the `static` token to the lexer and parses it as a modifier.
In check, `FullPatternStack::Kind::FieldDecl` is now used for both
static and non-static vars. Static vars get treated basically the same
as `NameBindingDecl`s.
Global initialization is used for static var initializers. To make the
necessary stack information available to `pattern_match.cpp`, the
`full_pattern_stack` and `decl_introducer_state_stack` are now popped
later in `handle_let_and_var.cpp`.
In lowering, each class's body is checked for `VarStorage` insts and
lowered the same as global vars.
Class vars are still restricted to simple `name: type` bindings, not
full patterns. This is now handled in the check phase instead of during
parsing.
This is in preparation for supporting `static var`.
Instead, use the inst category to select the right block stack. This
simplifies the API for adding insts, and in subsequent changes it will
enable certain inst kinds like `SpliceInst` to seamlessly function as
either procedural insts or pattern insts.
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
Do not treat it as a 1-tuple pattern as we used to. The design indicates
that `(pattern)` is invalid, but this appears to be an oversight, and
grouping parens appear to be the intended interpretation.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
This includes checking and lowering for concrete form literals. Support
for symbolic forms is future work.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Decouples associated constants from being special cased in let handlers.
Enforces associated constant grammar restrictions in parsing instead of
checking.
Closes#5411
In preparation for shifting from `TypeId`s potentially representing
attached types to always representing unattached types, using
[terminology suggested on
Discord](https://discord.com/channels/655572317891461132/963846118964350976/1359286326779973712).
This change causes us to track slightly more type spelling information
through SemIR.
One change that has significant impact on the SemIR output is that we
now build a `struct_type` instruction in each class representing the
types of the fields, including the spelling used for those types. This
is now no longer always identical to the corresponding canonical
`struct_type` for the object representation, so it's built separately
and owned by the class.
Also remove `TypeBlock` support entirely, as its only use was
representing `TupleType`s, which now use an `InstBlock`.
Parameter lists need substantially different treatment than tuple
patterns in other contexts, so this change splits them into separate
parse node kinds.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Note this is building on #4927 which factors out RegionStack, because
this heavily uses the region stack. However, it's a more complex level
of logic that appears specific to pattern handling.
I've moved InsertHere to pattern_match.cpp because it appears to be in
specific use there.
The "templated for consistency" variants felt a little confusing when I
was working on #4795, so suggesting to remove templating where it's not
helpful to instantiate (particularly when there were both templated and
non-templated variants). Note this leaves a `PeekIs<IdT>` because
there's indirection there, but that's more the exception than the rule.
This is a precondition for enabling the new pattern-matching subsystem
to support binding patterns that have `if` expressions in the type
position.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Note this isn't implementing checking through imports. The parse node
there is harder to access through the context, so would require
examining the entity in order to get the import declaration, to get at
the ImportIR. We also don't have a parse tree attached in that case, and
would need to add one to SemIR::File. But I believe we do want to add
that, so it's explicitly a TODO.
Note GetTokenText re-lexes literal values, so there's a bit of potential
overhead there. Not sure if we want a more efficient manner for
comparing in cases like this.
This is for consistency with #4120. Similar to that, we can use
overloads on the typed NodeId rather than individually named handlers.
There isn't the same caller benefit here though, since the calls from
check.cpp are already boilerplate.
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
This was previously discussed at
https://discord.com/channels/655572317891461132/655578254970716160/1209975051588210729.
I'm initiating this mainly because we typically use "id" suffixes to
indicate an `IdBase` being passed around and the non-id suffix of
`parse_node` suggests at it carrying more data than it actually does.
There used to be more reason for avoiding `node_id` because
`SemIR::InstId` used to be named `NodeId`, but that's no longer
necessary. As a consequence, I'd like to rename `parse_node` to more
precisely reflect its type.
In full, this is doing:
```
parse_node_kind -> node_kind
parse_node -> node_id
ParseNodeCategory -> NodeCategory
ParseNodeKind -> NodeKind
ParseNode -> NodeId
```
This is primarily in check and sem_ir, but with some `parse_node_kind`
references in parse too.
Pluralization is consistent with name forms on both sides, so that
wasn't part of my replacements.
Previously, we created scopes for implicit parameter lists and tuple
patterns, but that meant that bindings went out of scope too soon. We
now keep them in scope until the end of the enclosing declaration. This
is accomplished by pushing a scope for parameters when we handle a name
that might have them, and then popping the scope again if it turns out
that there were no parameters.
For a case such as:
```carbon
fn A(T:! type).B(U:! type).F(x: T, y: U) {
var z: T;
}
```
... we now have the following scopes in the stack:
- A parameter scope containing `T`.
- A class scope for `A(T:! type)`.
- A parameter scope containing `U`.
- A class scope for `A(T:! type).B(U:! type)`.
- A parameter scope containing `x: T` and `y: U`.
- A function body scope containing `z: T`.
The innermost scope when check processes a declaration of a function,
class, or similar is now often a parameter scope rather than the
enclosing scope in which the class or function is declared, so the
target scope is now passed explicitly into the modifier checking code
that wants to inspect that enclosing scope.
Goal is to increase type safety, though more work needs to be done (see
added TODOs).
Note that, after this change, check handlers corresponding to deleted
parse node kinds will no longer compile.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Lucile Rose Nihlen
oli-ej
Geoff Romer
Nicholas Bishop
Richard Smith
Elliott Kalt
Chandler Carruth
josh11b