Constructor types declared in the program hold class values as
checked-dynamic values since #1725. A fetched provenance source counts as
a program file, so the unused `@__PURE__` const typed `{ new (): any }` in
the provenance fixture now had a mapping, no longer elided, and its
initializer refused (SC1090). Fetched sources keep their constructor types
unmapped, as before #1725.
A `for` loop's initializer and a `for...of` loop's iterable run once, but
SC6101 counted any dynamic operation inside a loop statement's span, so
untyped setup there produced the warning and failed --fail-on=dynamic.
Loop work is now found by walking the IR: a loop's condition, update and
body repeat, its initializer and iterable do not. Locations could not
tell them apart, because lowering gives the index loop of a `for...of`
the whole statement's span.
The wrapper is dropped when its factory body moves to the top level, so
any other statement in the wrapper, in its CommonJS branch or in its AMD
branch would be lost. The check now matches the whole wrapper body and
keeps the original text for any other shape.
The arguments after a URL path that are evaluated ahead of the
conversion were keyed by the expression without its parentheses. When
the fs lowering read through a satisfies wrapper, it lowered the inner
expression again, so fs.chmodSync(url, mode() satisfies number) called
mode() twice. The saved arguments are now keyed and looked up without
their type-only wrappers (satisfies, as, type assertions, !), so each
runs once.
A constructor type whose instances are not one program class's, such as
`new () => unknown`, a type that also names static members (`{ readonly
schema: unknown; new (): unknown }`), an abstract constructor type over a
record, or construct overloads, did not map and refused with SC2001. Such
a type declared in the program now lowers as a checked-dynamic value, as
an `unknown` slot already holds a class value: the value keeps its class
identity, `new` through it constructs that class, static reads see that
class's statics, and the constructed value checks into the signature's
instance type. Library and package constructor types keep their fences.
Refs #1372
Co-authored-by: blurname <50226652+blurname@users.noreply.github.com>
A build now names the functions of the program's own files that compile
to the dynamic tier and likely run often, so a slow program with a little
untyped code says where the time goes:
warning SC6101: 3 functions that likely run often use untyped values, which runs slower than typed code:
advance (nbody.js:22): untyped JavaScript file, in a loop
...
- The functions come from the tier assignment lowering already makes
(Lowerer.dynamicFunctions). Without a profile, a function counts as
likely hot when a dynamic operation runs inside one of its loops, when
a loop calls it, or when it calls itself (lowering/dynamic-tier.ts).
- A function is named only when its source says why its values are
untyped: an `any` (for a for...of variable, the value it iterates), an
untyped JSON.parse result, or an untyped JavaScript file. Generated
%dyn.* helpers, module top levels and functions that are dynamic for an
operation without a static lowering are left out.
- At most five functions are named, most likely hot first, with the
total; dynamic-tier code in npm packages is counted per package on one
line. All of the warning's text is in diagnostics/dynamic-tier.ts.
- SC6101 opens the SC61xx band, performance notes, with a new
"performance" category in the diagnostics envelope; SC60xx stay the
divergences.
- scriptc build prints it after the divergence warnings, and the
executable cache stores it with the entry, so a cached build (including
the CLI's routed fast path) repeats it. scriptc coverage reports it, and
a comment-only edit no longer replays a verdict that carries it, since
its text holds line numbers.
- --no-dynamic-tier-warning leaves it out of build and coverage;
coverage --fail-on=dynamic fails on it.
- Docs: coverage.mdx (Dynamic tier, Gating builds and CI, the envelope
categories) and cli.mdx.
Chains of global one-character replacements (the HTML-escape idiom) run
as one scr_str_replace_chars call. It searched for the next match eight
bytes at a time and started the search over after each replacement.
It now reads 16-byte blocks with SSE2 or NEON (8-byte words elsewhere on
little-endian hosts) and replaces every match of a block before reading
the next one. The table of characters and replacements is kept for the
next call with the same immortal operands, which are the literals the
compiler passes, instead of being rebuilt from the replacement text on
every call.
- The number and whitespace scanners keep the cursor in locals and write
p->pos once: the runtime builds without strict aliasing, so a loop on
p->pos stored it after every byte.
- Typed arrays gather parsed elements in a 32-slot run and append them
with scr_arr_push_many instead of one push per element.
- The string scan shared by parse and stringify takes the index of the
first quote, backslash or control byte from the marked word on
little-endian hosts, and checks the last 1-7 bytes of a string as one
word, so a short plain string needs no byte loop.
- Typed record parsing computes once per record schema and parse which
field names hold no byte JSON would escape, instead of testing the
name on every direct key match.
- The mantissa converts to double through int64, and the positioned
error report stays out of line.
mentionsTypeParameter walked union constituents and type arguments
without remembering the types on its path. A parameter typed with an
alias that reaches itself through its own type arguments, such as
`type Tree = string | Tree[]` in `function f<T>(x: T, ...trees:
Tree[])`, recursed until the compiler ran out of stack. The walk now
skips a type it has already entered; a type parameter reached through
any other path is still found.
A dynamic method call on a class instance whose method name the program
also reads through a prototype (`X.prototype.map` anywhere) uses the
observed prototype slot: the callback descriptor read the method from the
instance's property bag, on the assumption that the bag answers every
read through the class prototype. An instance whose bag was built before
the class had prototype data reads as a fresh empty object, so the read
answered undefined and the call threw "... is not a function" (fast-check's
`integer({ min, max }).map(...)` once its result reaches the call through a
dynamic value).
The descriptor now reads the bag when the bag holds the name, own or
through its prototype, and otherwise the class's prototype data.
The TypeScript 7 parity lane checks every corpus program against a
recorded preflight and order baseline. 6950-string-field-fast-paths.ts
arrived without one; this records it from the current native lane.
When the Math functions evaluate their arguments into temporaries before
converting (an earlier argument whose ToNumber can run valueOf), a spread
argument's array is now copied where it is evaluated. Before, the
temporary held the array itself and its elements were read after the
conversions, so a valueOf that changed the array changed the values
passed, while JavaScript reads a spread's elements during argument
evaluation.
Number() of a string with an optional sign and 1 to 15 digits returns
the integer directly; every other string keeps the full StringToNumber
grammar, out of line.
split() with a separator collects its first batch of pieces before
creating the result, so the result is an inline array of exactly that
size, filled in place. A split's default limit skips the uint32
conversion, and pieces of a proven-ASCII string are created ASCII,
including the scratch pieces of split loops.
indexOf() from the start of a proven-ASCII string searches bytes
directly, and slice() of one skips the UTF-16 index map. The one-byte
case of the byte search reaches memchr without a stack frame.
5568-fs-cp-errors built its fixture in a /tmp directory named after the
program file, which it deletes and recreates. The Node oracle and the
native runs of one program run at the same time, so two runs with the
same name deleted each other's files and the program exited 1 on
random shards. Its root, and that of the five other corpus programs
that name a /tmp/scr-* directory after the program file alone, now
ends in the process id, as 5571-fs-cp-deep's does.
Chris Tate