`x!` performs no runtime check, but the compiler extracted the asserted arm
with a checked narrow, so a value that still held undefined or null threw
"TypeError: undefined is not representable in the target union" wherever it
was used. In Node the value reaches the operator, which converts it.
When `x!` is an operand of an arithmetic, bitwise or relational operator,
`+`, a compound assignment, a unary `-`, `+` or `~`, or an argument of a
Math function, and `x` is a union of numbers, strings, booleans, null and
undefined, the operand is now converted with ToNumber: undefined is NaN and
null is 0. As an operand of an equality operator, of `!`, of a template
span, of `+` with a string, or of a comparison with a string, the union
itself reaches the operator, so `x! === 0` is false and `${x!}` is
"undefined". Array and typed-array element reads keep their handling of a
missing element, and `+` whose result TypeScript types as a string keeps
the checked narrow where Node's result is NaN.
`x == null` on a union with both null and undefined arms evaluated its
operand twice, so an operand other than a plain read was refused. It is now
evaluated once into a hidden local.
Corpus 7392.
existsSync and the fs.promises functions accept a file: URL wherever
they accept a path. They convert it after their arguments are evaluated,
and a URL that does not convert gives false from existsSync and a promise
rejected with fileURLToPath's error from fs.promises, as in Node.
copyFileSync and renameSync check a string source for null bytes before
they convert a URL destination, and readFileSync checks a runtime
encoding before it converts a URL path, so the error Node reports first
is the one thrown.
Refs #1616
Co-authored-by: jlucaso1 <55464917+jlucaso1@users.noreply.github.com>
Node's constructNT reads _construct on the construction tick, so an
assignment after the constructor and before that tick replaces a scheduled
construct hook. The assignment was dropped, so the original hook ran. It
now lowers to stream.replaceConstruct, which swaps the hook while its tick
has not run and has no effect after it or on a stream without a hook.
Runtime decodeStrings and defaultEncoding values are read into locals
before the constructor evaluates the other option members, while Node
evaluates the members in order. A runtime value after a member whose value
has effects (a call or an assignment) now refuses instead of reading a
value that member could still change.
Lowering collects a function-local class with the body declaring it, so
a local subclass whose function lowers after its base's constructor was
missing from new.target's dispatch, which then answered with the base for
its instances. The refusal no longer depends on that order: the program's
function-local classes are found once, and one that extends the
constructor's class, directly or through other classes its extends
clauses name, refuses new.target as a collected one does.
A constructor's new.target dispatch skipped generic class families, so a
generic subclass instantiated only in a body lowered later answered with
the base's name, and `new.target === Base` held for its instances. A
family now has its own arm, tested by its instanceof interval, which holds
every instantiation: `new.target.name` reads the family's name and
comparisons with a program class are false. Under an instantiation, the
generic subclasses of its family are candidates too. `new.target` as a
value refuses generic subclasses, which have no common class value.
`new.target.name` reads a class's own static `name` field, which replaces
its name (a subclass has its own name); a static method `name` or a
non-string field is refused.
`C.call(...)` through a class value typed as `Base` may run a subclass's own
static `call`, which Node calls instead of the class constructor. The
constructor-call lowering now applies only when no class the receiver can
hold declares a static `call` or `apply`: the class and its bases (any
static member of that name, including accessors, fields without
initializers and computed names), and, for a receiver that may hold a
subclass, every subclass. Otherwise the call keeps its existing
diagnostic.
A Date is a refcounted object holding its time value, shared with the
checked-dynamic Date handle, so it keeps its identity through unknown.
Dates compile in arrays (includes, indexOf, lastIndexOf, join, default
sort by toString() text), in Date | undefined and Date | null slots, as
Map and Set keys and values, in index signatures, and in records, tuples,
class fields, closures, promises and generators. === compares identity,
relational operators compare time values, new Date(date) makes a new
Date, and JSON.stringify writes toJSON().
Closes#225
Co-authored-by: Max B <max@tfq.at>
Since Iterable<T> values compile (#1875), two diagnostics fixtures changed:
- fromentries-aliased-entries.ts compiles and prints what Node prints:
the entries' one array stays shared by both fields. It moves to the run
corpus as 7440-fromentries-aliased-entries.ts.
- iterator-slot-fences.ts no longer reports its Iterable<number>
parameter (SC2020) and the call through it (SC2004). That part leaves
the fixture, which keeps the class-iterator fence; corpus 7380-7383
cover Iterable values.
Inside a class constructor new.target is the class of the instance under
construction. A compiled new allocates the instance with its concrete class
before the constructor chain runs, and the class hierarchy is closed, so
new.target lowers to a static dispatch over the constructor's class and its
descendants (deepest instanceof first). new.target.name reads the exact
class's name and new.target === C is an exact-class test, without a class
value, so subclasses may construct with other signatures. new.target as a
class value requires every subclass to share the constructor's signature.
Plain functions and function-local subclasses keep explicit refusals.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Iterable<T> maps to a union of the sources that keep their own
representation (T[], Set<T>, Map<K, V> for [K, V] entries, string) and a
generator over T that holds every iterator. An array stays the same
multi-pass object; a generator stays single-pass. for-of gives the array
arm its own array loop, so iterating an Iterable that holds an array runs
at array speed. Spread, Array.from, the Set/Map constructors and
Object.fromEntries consume it; optional Iterables narrow into it;
generator functions may declare an Iterable return. Class iterables and
typed arrays are refused at the conversion with a named diagnostic.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A function expression stored in a function type with more parameters
folds `arguments.length` to that type's parameter count, the count every
call through the slot passes. A named expression that calls itself
through its own name passes only its declared parameters there, so no
constant answers both calls. Such a read now reports SC1090 with the
reason, and expressions that do not refer to their own name keep the
fold.
`.filter` with a written type predicate (`(p): p is Cat => ...`, or a
guard function passed as a value such as `filter(isDog)`) was refused with
SC1090, because TypeScript does not check the predicate. An inferred
predicate that keeps several union arms (`v => v !== undefined` over
`(string | number | undefined)[]`) was refused too.
The filter loop now keeps the receiver's element type, and the result
converts to the predicate's type element by element
(filter-predicates.ts):
- a union element to one of its arms, or to a union of some of its arms,
by its tag;
- a checked-dynamic element by dynCheck;
- a class instance to a subclass by its class;
- a tuple or record to one with the same fields, field by field.
An element the predicate's type does not describe, kept because the
predicate returned true for it, throws a catchable TypeError: "a kept
element is not a 'Cat' (a type predicate returned true for a value of
another type)". The diagnostics fixture filter-narrow.ts, which pinned
the three refusals, compiles now; corpus 7007 covers its cases.
Fixes#1680.
Generic arrow and function-expression bindings compile to shared
instances, and their declarations emit no store. Code that can run before
the declaration then diverged from Node.
- Inside a function, a nested function lowered before the declaration
reads the binding through a TDZ box that nothing initialized. That
covers closures above the declaration and hoisted function
declarations. Such a read threw a ReferenceError even after the
declaration ran. The declaration now stores the instance its declared
signature pins into that box.
- At module scope, calls and pinned value reads went straight to the
instances even when a hoisted function or an earlier closure ran them
before the declaration. A binding with such a use now has a flag that
its declaration sets.
- Uses that can run first check the flag.
- A let or const throws Node's ReferenceError before the arguments
run.
- A var runs the arguments and then throws "is not a function".
- Uses that follow the declaration stay direct calls: later statements,
closures created after it, its own initializer, and function
declarations that only such code calls.
A var binding inside a function that is called from a place that can run
before its declaration would need a per-call flag shared with its
closures. That shape now fails with SC1090 instead of calling the
instance.
The runtime call reads the cert and key options before the SNICallback,
so a cert or key initializer after the callback that reassigned the
callback's binding changed the callback the server used, and the server
could serve the wrong certificate. When SNICallback comes before a cert
or key entry, the callback is now saved just before the next of them is
evaluated. With the callback read in order, a callback expression with
side effects lowers instead of being refused.
tls.createServer({ cert, key, SNICallback }) hands each ClientHello's
servername to the callback and serves the SecureContext it answers,
synchronously or later, or the default cert and key when it answers none.
An error answer closes that connection. This uses the SNI handling that
http2.createSecureServer already has. A callback expression with side
effects, or SNICallback combined with ALPNProtocols, minVersion, maxVersion
or the other options the runtime walk reads, fails with SC2020.
A tls.connect or https.request client whose peer closes or resets the
connection before the handshake completes now fails with Node's ECONNRESET
"Client network socket disconnected before secure TLS connection was
established" instead of closing without an error.
Refs #1438
Co-authored-by: saboursepideh <25549001+saboursepideh@users.noreply.github.com>
readFileSync, writeFileSync, appendFileSync, statSync, lstatSync,
readdirSync, mkdirSync, rmSync, rmdirSync, mkdtempSync, accessSync,
unlinkSync, chmodSync, chownSync, lchownSync, truncateSync, copyFileSync,
renameSync, realpathSync, realpathSync.native, openSync and opendirSync
accept a file: URL wherever they accept a path. The URL converts as
fileURLToPath converts it, with Node's errors for other schemes, hosts,
encoded separators and null bytes.
Arguments after a URL path that have side effects are evaluated into
hidden locals before the conversion, so they run even when it throws. A
URL path after a string path, or with options that are not literals,
fails with SC2020, because Node checks those arguments before it converts
the URL. existsSync and the fs.promises functions also fail with SC2020
for URL paths: existsSync answers false for a URL it cannot convert, and
fs.promises reports conversion errors as rejections.
Fixes#1616
Co-authored-by: jlucaso1 <55464917+jlucaso1@users.noreply.github.com>
Chris Tate