Commit Graph
5 Commits
Author SHA1 Message Date
simontran7 64ce58dd64 fix malformed parse tree for invalid let struct pattern (#7782)
Fixes the malformed parse tree produced for an invalid let struct
pattern containing a single identifier (e.g., `let {s};`).

As pointed out by @DavidLoftus, the parser should produce a parse tree
similar to that of `let {ref s};`, since both are missing a binding
power operator `:`, and both do not have a `.` preceding the identifier
(i.e., `state.in_field_shorthand_pattern == true`).

This means that the parser can produce an the `InvalidParse` node just
as it does for `let {ref s};`.

Closes #7674
2026-09-15 23:10:17 +00:00
Lucile Rose Nihlen 2952ec9c10 Fix a crash when checking a nested tuple-pattern (#7716)
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.
2026-09-04 01:22:16 +00:00
Lucile Rose Nihlen 91c1e1049d Add parsing of default value exprs in pattern lists (#7631)
Adds parsing support only for default value expressions in pattern
lists, including leaving the default value unspecified with an
underscore `_`.

Per #7521.
2026-09-01 01:19:13 +00:00
Geoff Romer 6429c1655c Make the tree structure more explicit in parse dumps (#7591)
It's hard to track 2-space indent levels across large vertical gaps, and
it can be hard to suppress the instinct to read the dump as if it were
preorder. This change introduces a new dump mode that addresses both
problems by using box-drawing characters to explicitly represent the
parent-child edges of the tree. This new mode is the default, but the
old behavior remains available with
`--parse-dump-format=yaml-postorder`.
2026-07-31 16:44:18 +00:00
oli-ej a683fb574b Add initial support for parsing struct patterns (#7446)
Implements parsing of struct patterns as per
https://github.com/carbon-language/carbon-lang/issues/6680.

This handles the full and short syntax given in the [design
doc](https://github.com/carbon-language/carbon-lang/blob/trunk/docs/design/pattern_matching.md#struct-patterns),
but the handling of the shorthand syntax may need to change as I move on
to implementing Check support (currently the shorthand is represented as
one of `LetBindingPattern`, `VarBindingPattern`, or `VariablePattern`).

This implementation assumes that the answer to
https://github.com/carbon-language/carbon-lang/issues/7404 is that
trailing commas are allowed in the struct pattern, except for the case
where an `_` is present, in which case the next token must be the
closing brace `}`.
2026-07-30 16:37:46 +00:00