Store parser errors, source range filenames, source code filenames,
module source, and Rust parser errors as UTF-16 where they flow back
into JavaScript-visible strings. Keep byte-oriented source buffers
byte-backed.
Remove temporary PrimitiveString, ByteString, and UTF-8 detours from
JSON, RegExp, module debug logging, print formatting, and tests.
By default, `rustfmt` persists the import granularity. In practice, most
Rust code has import granularity "Module" due to LSP's actions.
"Item" gets rid of import groupings and achieves cleaner diffs and
better conflict resolution. Better greppability is a positive side
effect.
Note: it's an unstable rustfmt feature. `cargo +nightly fmt` must be
used instead of `cargo fmt`.
Parenthesized import calls are valid callees for new expressions. The
unparenthesized form remains a syntax error, but the grouped expression
must parse and then fail at runtime if the produced Promise is not a
constructor.
Add syntax coverage for both forms.
Run deferred parameter validation whenever the surrounding context is
already strict, not only when a function body contains a Use Strict
Directive. Destructured parameter names are collected while parsing the
parameter list, so eval and arguments bindings in patterns otherwise
escaped the strict-mode early error for functions and methods.
Add parser coverage for sloppy destructuring remaining accepted, strict
source being rejected, and class methods applying their strict context.
Parse await through the unary-expression path so the existing
exponentiation early error also applies to AwaitExpression. This keeps
parenthesized await expressions valid while rejecting await on the
left-hand side of **.
Add parser coverage for the async-function constructor case.
NamedEvaluation for assignment only applies when the left hand side is
an IdentifierRef. Parenthesized identifiers are still assignment
targets, but are not IdentifierRefs, so `(fn) = function () {}` must
leave the function anonymous.
Carry the parser's parenthesized-LHS bit into assignment codegen. Use
it when setting pending_lhs_name for plain and logical assignment, and
cover parenthesized assignment targets in the function-name tests.
YieldExpression carries the surrounding In grammar parameter into its
operand. The parser was always parsing yield operands with In enabled,
accepting invalid generator for-loop heads containing `yield ... in`.
GeneratorExpression parses its optional binding identifier with the
Yield grammar parameter enabled, so `yield` is not a valid name for
a named generator expression. Reject it while still allowing sloppy
generator declarations named `yield`, and add syntax coverage for
both cases.
ArrowFunction carries the surrounding In grammar parameter into its
ConciseBody. The parser recognized arrows in for-loop init expressions,
but parsed expression bodies with In always enabled, so
`for (x => 0 in 1;;)` was accepted as a normal for loop.
Thread the existing forbidden-token state through arrow parsing so the
body leaves `in` for the for-head parser. That parser then rejects the
arrow as an invalid for-in left-hand side. Add coverage in the for-loop
no-In syntax test.
Treat ordinary and generator function expressions inside class static
blocks as boundaries for await binding names, while still rejecting
await as an arrow parameter in the static block itself.
Parse field initializers without inheriting an enclosing async
function's await-expression context, so script field initializers can
resolve await as an identifier while computed field names still use the
enclosing expression context.
Cover static block function expressions, class field initializers, and
the AST shape for an await arrow inside a nested function.
Formal parameter early errors depend on the final parameter-list shape.
A duplicate in `function(a, a, ...rest)` was accepted because the
duplicate appeared before the rest parameter was seen.
Track the final simple-parameter-list result before checking duplicate
names, and enforce `UniqueFormalParameters` for method definitions. Add
coverage for sloppy functions with a later rest parameter and sloppy
object methods.
The Rust AST kept every scope in Rc<RefCell<ScopeData>>. The Rc made
the AST !Send (cross-thread codegen needed unsafe impl Send), and the
RefCell added a runtime borrow check on every hot-path read.
AST nodes (Block, FunctionBody, Program, SwitchStatement, SwitchCase)
now hold a ScopeId index into ScopeArena. The scope collector and
codegen take &mut/&ScopeArena, so the borrow checker enforces the
previously-implicit invariant that two phases never touch the same
scope at once.
ParsedProgram is now naturally Send. The unsafe impl Send and the
arc_with_non_send_sync allow go away. CompiledProgram keeps its
hand-rolled Send impl because it carries codegen-time state outside
the AST.
FunctionDeclarationData::is_hoisted was a Cell<bool> only because the
old &[ScopeRecord] traversal couldn't get &mut to the AST. It is now
a plain bool.
Identifier::name was SharedUtf16String (Rc<Utf16String>), so equality
checks against literals walked the slice and the Rc made the AST
!Send.
Replace it with a StringId (u32 index) backed by a StringInterner on
AstArena. Repeated names dedupe to the same id, so name comparisons
collapse to u32 == u32. The lexer's short/recent identifier caches
and the shared_identifier_value field on Token go away; the interner
already deduplicates everything.
Methods that previously took &mut IdentifierArena now also take
&StringInterner so they can resolve names from StringId during
analyze. Codegen helpers in bytecode/codegen.rs uniformly take
&AstArena. Generator gains intern_identifier_id, intern_property_key_id,
and intern_string_id helpers.
scope_collector now reaches Identifier through &mut IdentifierArena
indexing instead of through Rc<Identifier>'s shared reference, so the
Cell<> wrappers on local_type, local_index, is_global,
is_inside_scope_with_eval, and declaration_kind no longer earn their
keep.
Replace each Cell<T> with a plain T. The borrow checker now enforces
the existing "only scope_collector mutates these post-parse"
invariant. Shrinks Identifier and removes a layer of indirection on
hot-path field reads in codegen and ast_dump.
Replace per-AST-node Rc<Identifier> with a Copy IdentifierId index
into a Vec<Identifier> arena, plumbed through Parser, scope_collector,
codegen, ast_dump, and the FFI. The arena lives on the parser during
parse, ships out via Arc<AstArena> on ParsedProgram, and is shared by
each child Generator and FunctionPayload through Arc clones.
Eliminates the per-occurrence Rc::new in the parser: every identifier
reference, parameter binding, function name, class name, and
binding-pattern target lands in the arena's Vec instead of getting its
own malloc plus Rc control block. Identifier field reads in codegen
become direct array indexing.
Identifier still carries Cell<>-wrapped scope-analysis state, so
AstArena is not yet Send + Sync; the existing unsafe-impl-Send wrapper
on ParsedProgram covers cross-thread handoff. Removing the Cells is
the next step.
The regex literal handle is shared between AST clones (e.g. class
field initializers reuse the same compiled regex), so shared ownership
has to stay. Switch from Rc to Arc and from Cell<*mut c_void> to
AtomicPtr<c_void> so the regex can travel with a function payload to
a worker thread without UB on the non-atomic Rc refcount.
The Rust parser used to copy several "rule_start"-derived positions
from the C++ implementation: every identifier inside a binding pattern
inherited the pattern's `[`/`{` position, every property identifier
after `.` inherited the period's position, every spread element
inherited the surrounding `[`/`{` position, and identifier-name
property keys inherited the object/class start position. This was
useful while comparing bytecode against the C++ port; with the C++
side gone, those quirks just hide the actual source positions in
source maps and devtools.
Drop the dedicated `binding_pattern_start` parser field and the
`ident_pos_override` parameter on `parse_property_key`, and capture
each identifier's own start position at the consume site.
Add an AST snapshot test that pins the new per-identifier positions
for object, array, nested, and parameter binding patterns.
The parser used to suppress the arguments/eval reference check via a
state flag that was set during the entire `parse_property_key` call.
That was over-broad: identifiers inside a computed property key like
`{ [arguments]: 1 }` are real references, but the flag silenced their
check too, leaving the function unmarked as needing the arguments
object. Reading the resulting property at runtime crashed.
Replace the flag with a `consume_property_key_token()` method used at
the specific consume sites for the property key token itself, so the
suppression is narrow. Inner consumes inside computed keys now go
through regular `consume()` and run the check normally.
Add a focused AST snapshot test covering plain, shorthand, computed,
binding-pattern, and method-name property-key cases.
FunctionTable::extract_reachable() used to rediscover a function's
nested functions by walking the full body and parameter list during
bytecode generation. This is hot during page loading because creating
every lazy SFD pays for an extra structural AST traversal.
Record each parser-created function's direct child function ids while
parsing instead. Extraction can then recursively move that known
subtree without scanning the enclosing function again.
Keep the old structural scan for codegen-synthesized wrappers, such as
class field initializers, where no parser function context exists.
This preserves the sparse FunctionTable storage while making the common
extraction path proportional to the nested function count.
Now that LibRegex is safe to use (for parsing) off the main thread,
we can validate regex literals directly while parsing JavaScript.
This allows us to remove the deferred regex compilation pass that we
previously ran on the main thread after parsing JS in the background.
- Restrict catch parameter conflict check to only direct children
of the catch body block, not nested scopes
- Set new_target_is_valid for dynamic function compilation (new
Function)
- Move check_parameters_post_body before flag restoration in
parse_method_definition so generator methods inside static init
blocks correctly allow 'await' as a parameter name
Check identifier name validity for destructuring assignment pattern
bound names, and validate arrow function parameters after the arrow
is confirmed rather than during speculative parameter parsing.
This fixes arguments/eval as destructuring assignment targets and as
arrow function parameter names in strict mode.
Arrow functions don't have their own new.target binding -- they
inherit from the enclosing scope. At the global level, there is no
enclosing function, so new.target inside a global arrow is invalid.
Add a new_target_is_valid flag to ParserFlags that is set to true
when entering regular (non-arrow) function bodies, method
definitions, and class static init blocks. Arrow functions inherit
the flag from their enclosing scope rather than setting it.
- Reject `true`, `false`, `null` as label identifiers
- Reject generator declarations in if-statement bodies (not covered
by Annex B)
- Reject `await` as label in class static init blocks and modules
- Reject `arguments` in class static initialization blocks
- Reject generator shorthand without method body in object literals
- Reject `get constructor()` / `set constructor()` in class bodies
- Reject `super.#private` member access
