isArray() preserve mutability and element type #48228

jablko · 2022-03-11T21:58:45Z

Reopening #42316, with any and unknown backward compatibility: #42316 (comment)

There are a couple of related issues here:

Array.isArray() narrows readonly T[] -> mutable any[]
Consequently the false branch doesn't remove readonly T[]
It loses the element or iterated type of wider types ArrayLike<T> and Iterable<T>

#17002 concerns issues 1 and 2. 1 and 3 are pretty similar --- #33700 calls out issue 3, the still-wider type Iterable<T> vs. readonly T[].

#42316 fixed #17002 (1 and 2) but not #33700 (issue 3), by changing the return type from arg is any[] -> arg is readonly unknown[]. That preserves mutability and therefore removes it from the false branch. It narrows:

T[] -> T[] & readonly unknown[] (which is mutable because the T[] component is mutable)
readonly T[] -> readonly T[] & readonly unknown[] (immutable)

It also preserves the element type of readonly T[].

#42316 was closed because it narrowed any and unknown -> readonly unknown[] vs. any[] (which is the current behavior), breaking code that relies on unknown narrowing to mutable, or narrowing to elements of type any:

declare const u: unknown;
if (Array.isArray(u)) {
  u[1] = 12;
  u[1].length;
}

The current behavior is exceedingly permissive in those cases. The change added errors that weren't there before, but aren't necessarily correct or incorrect, because any and unknown can be anything. The fix wasn't worth the breakage: #42316 (comment)

🩹 Proposed solution

This PR addresses backward compatibility, and also fixes #33700 (issue 3), by instead adding overloads for:

    isArray<T>(arg: ArrayLike<T>): arg is readonly T[];
    isArray<T>(arg: Iterable<T>): arg is readonly T[];

This fixes 1, 2, and 3, for ArrayLike<T>, Iterable<T>, and their narrower types, including readonly T[], while preserving the current behavior for everything else, including any and unknown.

Fixes #17002
Fixes #33700
Fixes #41808

⏯️ Playground link

Workbench repro.

🧑‍💻 Code

// @target: es2015
// @errors: 2322 4104

//interface ArrayConstructor {
//  isArray<T>(arg: ArrayLike<T>): arg is readonly T[];
//  isArray<T>(arg: Iterable<T>): arg is readonly T[];
//}

// https://github.com/microsoft/TypeScript/issues/17002
// Preserves mutability, false branch removes arrays, mutable or not

declare const mutable: string | string[];
if (Array.isArray(mutable)) {
  const stillMutable: string[] = mutable;
} else {
  const narrowed: string = mutable;
}

declare const immutable: string | readonly string[];
if (Array.isArray(immutable)) {
  const notMutable: string[] = immutable; // Should fail: readonly string[] isn't assignable to string[]
} else {
  const narrowed: string = immutable;
}

// https://github.com/microsoft/TypeScript/issues/33700
// Preserves element or iterated type of wider types

declare const arrayLike: string | ArrayLike<string>;
if (Array.isArray(arrayLike)) {
  const arrayOfElementType: readonly string[] = arrayLike;
  const notArrayOfAny: readonly void[] = arrayLike; // Should fail: string isn't assignable to void
}

declare const iterable: string | Iterable<string>;
if (Array.isArray(iterable)) {
  const arrayOfIteratedType: readonly string[] = iterable;
  const notArrayOfAny: readonly void[] = iterable; // Should fail: string isn't assignable to void
}

// https://github.com/microsoft/TypeScript/pull/42316#discussion_r823218462
// any and unknown backward compatibility

declare const any: any;
if (Array.isArray(any)) {
  const mutableArrayOfAny: void[] = any;
  const notAny: void = any; // Should fail: any[] isn't assignable to void
}

declare const unknown: unknown;
if (Array.isArray(unknown)) {
  const mutableArrayOfAny: void[] = unknown;
  const notAny: void = unknown; // Should fail: any[] isn't assignable to void
}

🙁 Actual behavior

// https://github.com/microsoft/TypeScript/issues/17002
// Preserves mutability, false branch removes arrays, mutable or not

declare const immutable: string | readonly string[];
if (Array.isArray(immutable)) {
  const notMutable: string[] = immutable; // ❌ No error: You're free to mutate immutable
} else {
  const narrowed: string = immutable; // ❌ False branch removes mutable arrays only
}

// https://github.com/microsoft/TypeScript/issues/33700
// Preserves element or iterated type of wider types

declare const iterable: string | Iterable<string>;
if (Array.isArray(iterable)) {
  const arrayOfIteratedType: readonly string[] = iterable;
  const notArrayOfAny: readonly void[] = iterable; // ❌ No Error: Iterable<string> -> any[]
}

$ tsc --target es2015 input.ts 
input.ts:8:9 - error TS2322: Type 'string | readonly string[]' is not assignable to type 'string'.
  Type 'readonly string[]' is not assignable to type 'string'.

8   const narrowed: string = immutable; // ❌ False branch removes mutable arrays only
          ~~~~~~~~


Found 1 error.

🙂 Expected behavior

With this PR:

// https://github.com/microsoft/TypeScript/issues/17002
// Preserves mutability, false branch removes arrays, mutable or not

declare const immutable: string | readonly string[];
if (Array.isArray(immutable)) {
  const notMutable: string[] = immutable; // ✔️ readonly string[] isn't assignable to string[]
} else {
  const narrowed: string = immutable; // ✔️ False branch removes arrays, mutable or not
}

// https://github.com/microsoft/TypeScript/issues/33700
// Preserves element or iterated type of wider types

declare const iterable: string | Iterable<string>;
if (Array.isArray(iterable)) {
  const arrayOfIteratedType: readonly string[] = iterable;
  const notArrayOfAny: readonly void[] = iterable; // ✔️ string isn't assignable to void
}

$ node built/local/tsc.js --target es2015 input.ts 
input.ts:6:9 - error TS4104: The type 'readonly string[]' is 'readonly' and cannot be assigned to the mutable type 'string[]'.

6   const notMutable: string[] = immutable; // ✔️ readonly string[] isn't assignable to string[]
          ~~~~~~~~~~

input.ts:17:9 - error TS2322: Type 'readonly string[]' is not assignable to type 'readonly void[]'.
  Type 'string' is not assignable to type 'void'.

17   const notArrayOfAny: readonly void[] = iterable; // ✔️ string isn't assignable to void
           ~~~~~~~~~~~~~


Found 2 errors in the same file, starting at: input.ts:6

typescript-bot · 2022-03-11T21:58:57Z

The TypeScript team hasn't accepted the linked issue #33700. If you can get it accepted, this PR will have a better chance of being reviewed.

typescript-bot · 2022-03-11T21:59:04Z

The TypeScript team hasn't accepted the linked issue #33700. If you can get it accepted, this PR will have a better chance of being reviewed.

RyanCavanaugh · 2022-03-11T23:01:06Z

@DanielRosenwasser let's discuss this next week - seems promising

SPGoding · 2022-06-02T19:38:36Z

Not sure if I get this right, but the immutable case only seems to work because both string and readonly string[] are Iterable<string>. If you change string to number instead the type checker reverts back to the old behavior:

// https://github.com/microsoft/TypeScript/issues/17002

declare const immutable: number | readonly number[];
if (Array.isArray(immutable)) {
  const notMutable: number[] = immutable; // ❌ No error: type of immutable is `any[]`
} else {
  const narrowed: number = immutable; // ❌ Error: `readonly number[]` is not removed from false branch.
}

src/lib/es5.d.ts

tests/baselines/reference/destructuringParameterDeclaration4.errors.txt

jakebailey · 2024-07-25T04:17:52Z

@typescript-bot test it

typescript-bot · 2024-07-25T04:17:56Z

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
`test top400`	✅ Started	👀 Results
`user test this`	✅ Started	👀 Results
`run dt`	✅ Started	👀 Results
`perf test this faster`	✅ Started	👀 Results

typescript-bot · 2024-07-25T04:37:40Z

Hey @jakebailey, the results of running the DT tests are ready.

There were interesting changes:

Branch only errors:

Package: ramda
Error:

Error: 
/mnt/vss/_work/1/DefinitelyTyped/types/ramda/test/map-tests.ts
  7:38  error  TypeScript@local compile error: 
No overload matches this call.
  The last overload gave the following error.
    Type 'number' is not assignable to type 'Iterable<unknown>'.
      Property '[Symbol.iterator]' is missing in type '{}' but required in type 'Iterable<unknown>'  @definitelytyped/expect
  7:44  error  TypeScript@local compile error: 
No overload matches this call.
  The last overload gave the following error.
    Type 'number' is not assignable to type 'Iterable<unknown>'.
      Property '[Symbol.iterator]' is missing in type '{}' but required in type 'Iterable<unknown>'  @definitelytyped/expect

✖ 2 problems (2 errors, 0 warnings)

    at combineErrorsAndWarnings (/mnt/vss/_work/1/DefinitelyTyped/node_modules/.pnpm/@[email protected][email protected]/node_modules/@definitelytyped/dtslint/dist/index.js:194:28)
    at runTests (/mnt/vss/_work/1/DefinitelyTyped/node_modules/.pnpm/@[email protected][email protected]/node_modules/@definitelytyped/dtslint/dist/index.js:186:20)

Package: node
Error:

Error: 
/mnt/vss/_work/1/DefinitelyTyped/types/node/test/stream.ts
  659:5  error  TypeScript@local tsconfig.dom.json, local tsconfig.non-dom.json expected type to be:
  Promise<any[] | undefined>
got:
  Promise<readonly unknown[] | undefined>  @definitelytyped/expect

✖ 1 problem (1 error, 0 warnings)

    at combineErrorsAndWarnings (/mnt/vss/_work/1/DefinitelyTyped/node_modules/.pnpm/@[email protected][email protected]/node_modules/@definitelytyped/dtslint/dist/index.js:194:28)
    at runTests (/mnt/vss/_work/1/DefinitelyTyped/node_modules/.pnpm/@[email protected][email protected]/node_modules/@definitelytyped/dtslint/dist/index.js:186:20)

You can check the log here.

typescript-bot · 2024-07-25T04:40:29Z

@jakebailey Here are the results of running the user tests with tsc comparing main and refs/pull/48228/merge:

Something interesting changed - please have a look.

Details

effect

packages/schema/benchmark/tsconfig.json

[NEW] error TS4104: The type 'readonly A[]' is 'readonly' and cannot be assigned to the mutable type 'A[]'.
- packages/effect/src/Array.ts#L146

tsconfig.json

[NEW] error TS4104: The type 'readonly A[]' is 'readonly' and cannot be assigned to the mutable type 'A[]'.
- packages/effect/src/Array.ts#L146 in packages/effect/tsconfig.src.json
- packages/effect/src/Array.ts#L146 in packages/effect/tsconfig.build.json

tsconfig.build.json

[NEW] error TS4104: The type 'readonly A[]' is 'readonly' and cannot be assigned to the mutable type 'A[]'.
- packages/effect/src/Array.ts#L146 in packages/effect/tsconfig.build.json

tsconfig.base.json

[NEW] error TS4104: The type 'readonly A[]' is 'readonly' and cannot be assigned to the mutable type 'A[]'.
- packages/effect/src/Array.ts#L146 in tsconfig.base.json

typescript-bot · 2024-07-25T05:02:13Z

@jakebailey
The results of the perf run you requested are in!

Here they are:

tsc

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-Unions - node (v18.15.0, x64)}
_Errors	₃₀	₃₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_62,153	_62,170	_{+17 (+ 0.03%)}	_~	_~	_{p=0.001 n=6}
_Types	_50,242	_50,246	_{+4 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{194,193k (± 1.03%)}	_{193,555k (± 0.92%)}	_~	_192,297k	_195,925k	_{p=0.230 n=6}
_{Parse Time}	_{1.30s (± 0.75%)}	_{1.30s (± 1.23%)}	_~	_1.27s	_1.31s	_{p=0.931 n=6}
_{Bind Time}	_0.71s	_0.71s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.56s (± 0.50%)}	_{9.54s (± 0.57%)}	_~	_9.48s	_9.63s	_{p=0.517 n=6}
_{Emit Time}	_{2.75s (± 0.36%)}	_{2.72s (± 0.79%)}	_{-0.03s (- 0.91%)}	_2.70s	_2.76s	_{p=0.042 n=6}
_{Total Time}	_{14.32s (± 0.28%)}	_{14.27s (± 0.39%)}	_~	_14.22s	_14.38s	_{p=0.053 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₇	₇	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_945,532	_946,486	_{+954 (+ 0.10%)}	_~	_~	_{p=0.001 n=6}
_Types	_409,507	_410,263	_{+756 (+ 0.18%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{1,221,174k (± 0.00%)}	_{1,222,078k (± 0.01%)}	_{+904k (+ 0.07%)}	_1,221,971k	_1,222,178k	_{p=0.005 n=6}
_{Parse Time}	_{6.61s (± 0.73%)}	_{6.59s (± 0.42%)}	_~	_6.54s	_6.62s	_{p=0.418 n=6}
_{Bind Time}	_{1.86s (± 0.65%)}	_{1.86s (± 0.34%)}	_~	_1.85s	_1.87s	_{p=0.673 n=6}
_{Check Time}	_{31.18s (± 0.48%)}	_{31.09s (± 0.36%)}	_~	_30.94s	_31.24s	_{p=0.261 n=6}
_{Emit Time}	_{15.01s (± 0.48%)}	_{15.00s (± 0.56%)}	_~	_14.91s	_15.09s	_{p=0.935 n=6}
_{Total Time}	_{54.66s (± 0.35%)}	_{54.54s (± 0.16%)}	_~	_54.46s	_54.67s	_{p=0.173 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,324,875	_2,325,177	_{+302 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_949,556	_949,698	_{+142 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,222,596k (± 0.00%)}	_{2,222,894k (± 0.00%)}	_{+298k (+ 0.01%)}	_2,222,861k	_2,222,945k	_{p=0.005 n=6}
_{Parse Time}	_{6.65s (± 0.21%)}	_{6.63s (± 0.20%)}	_{-0.02s (- 0.28%)}	_6.61s	_6.65s	_{p=0.048 n=6}
_{Bind Time}	_{2.32s (± 0.22%)}	_{2.33s (± 0.70%)}	_~	_2.31s	_2.35s	_{p=0.276 n=6}
_{Check Time}	_{73.06s (± 0.14%)}	_{73.13s (± 0.36%)}	_~	_72.87s	_73.59s	_{p=1.000 n=6}
_{Emit Time}	_{0.14s (± 3.77%)}	_0.14s	_~	_~	_~	_{p=0.174 n=6}
_{Total Time}	_{82.17s (± 0.13%)}	_{82.23s (± 0.29%)}	_~	_82.01s	_82.67s	_{p=0.810 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,230,046	_1,230,222	_{+176 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_265,645	_265,751	_{+106 (+ 0.04%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,347,376k (± 0.02%)}	_{2,347,588k (± 0.02%)}	_~	_2,347,109k	_2,348,308k	_{p=0.575 n=6}
_{Parse Time}	_{4.99s (± 1.02%)}	_{5.00s (± 0.93%)}	_~	_4.96s	_5.06s	_{p=0.470 n=6}
_{Bind Time}	_{1.90s (± 0.43%)}	_{1.91s (± 1.12%)}	_~	_1.89s	_1.95s	_{p=0.270 n=6}
_{Check Time}	_{34.71s (± 0.32%)}	_{34.68s (± 0.57%)}	_~	_34.46s	_34.89s	_{p=0.810 n=6}
_{Emit Time}	_{3.29s (± 0.79%)}	_{3.28s (± 1.61%)}	_~	_3.19s	_3.35s	_{p=0.630 n=6}
_{Total Time}	_{44.90s (± 0.23%)}	_{44.90s (± 0.51%)}	_~	_44.58s	_45.15s	_{p=0.936 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,230,046	_1,230,222	_{+176 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_265,645	_265,751	_{+106 (+ 0.04%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{2,421,996k (± 0.04%)}	_{2,422,079k (± 0.01%)}	_~	_2,421,780k	_2,422,282k	_{p=0.810 n=6}
_{Parse Time}	_{6.20s (± 0.73%)}	_{6.19s (± 0.26%)}	_~	_6.17s	_6.21s	_{p=0.810 n=6}
_{Bind Time}	_{2.03s (± 0.67%)}	_{2.06s (± 0.80%)}	_{+0.03s (+ 1.40%)}	_2.03s	_2.08s	_{p=0.019 n=6}
_{Check Time}	_{41.27s (± 0.38%)}	_{41.26s (± 0.38%)}	_~	_41.12s	_41.55s	_{p=0.748 n=6}
_{Emit Time}	_{3.98s (± 1.54%)}	_{4.09s (± 2.52%)}	_{+0.11s (+ 2.85%)}	_4.01s	_4.30s	_{p=0.020 n=6}
_{Total Time}	_{53.49s (± 0.35%)}	_{53.60s (± 0.32%)}	_~	_53.46s	_53.82s	_{p=0.092 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_258,471	_258,502	_{+31 (+ 0.01%)}	_~	_~	_{p=0.001 n=6}
_Types	_105,534	_105,570	_{+36 (+ 0.03%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{429,101k (± 0.01%)}	_{429,458k (± 0.06%)}	_{+358k (+ 0.08%)}	_429,069k	_429,761k	_{p=0.031 n=6}
_{Parse Time}	_{3.35s (± 0.77%)}	_{3.36s (± 0.78%)}	_~	_3.31s	_3.38s	_{p=0.254 n=6}
_{Bind Time}	_{1.33s (± 1.31%)}	_{1.33s (± 0.74%)}	_~	_1.32s	_1.34s	_{p=0.315 n=6}
_{Check Time}	_{18.03s (± 0.35%)}	_{17.98s (± 0.23%)}	_~	_17.93s	_18.03s	_{p=0.295 n=6}
_{Emit Time}	_{1.63s (± 0.85%)}	_{1.64s (± 1.37%)}	_~	_1.61s	_1.67s	_{p=0.124 n=6}
_{Total Time}	_{24.32s (± 0.35%)}	_{24.32s (± 0.14%)}	_~	_24.26s	_24.35s	_{p=0.936 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₃₅	₃₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_224,931	_224,969	_{+38 (+ 0.02%)}	_~	_~	_{p=0.001 n=6}
_Types	_94,146	_94,191	_{+45 (+ 0.05%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{370,163k (± 0.04%)}	_{370,051k (± 0.02%)}	_~	_369,951k	_370,172k	_{p=0.173 n=6}
_{Parse Time}	_{3.43s (± 0.63%)}	_{3.44s (± 0.59%)}	_~	_3.41s	_3.47s	_{p=0.685 n=6}
_{Bind Time}	_{1.92s (± 0.86%)}	_{1.93s (± 0.87%)}	_~	_1.90s	_1.94s	_{p=0.154 n=6}
_{Check Time}	_{19.34s (± 0.21%)}	_{19.34s (± 0.44%)}	_~	_19.23s	_19.43s	_{p=0.748 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.69s (± 0.25%)}	_{24.71s (± 0.31%)}	_~	_24.60s	_24.79s	_{p=0.747 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₁₁	₁₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,985,984	_2,989,692	_{+3,708 (+ 0.12%)}	_~	_~	_{p=0.001 n=6}
_Types	_1,027,145	_1,030,096	_{+2,951 (+ 0.29%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{3,110,036k (± 0.00%)}	_{3,113,574k (± 0.00%)}	_{+3,539k (+ 0.11%)}	_3,113,450k	_3,113,634k	_{p=0.005 n=6}
_{Parse Time}	_{17.19s (± 0.38%)}	_{17.13s (± 0.23%)}	_~	_17.10s	_17.19s	_{p=0.126 n=6}
_{Bind Time}	_{5.25s (± 1.73%)}	_{5.26s (± 2.07%)}	_~	_5.20s	_5.48s	_{p=0.870 n=6}
_{Check Time}	_{96.24s (± 0.28%)}	_{96.46s (± 0.56%)}	_~	_95.91s	_97.43s	_{p=0.689 n=6}
_{Emit Time}	_{24.90s (± 0.91%)}	_{25.05s (± 0.58%)}	_~	_24.91s	_25.29s	_{p=0.066 n=6}
_{Total Time}	_{143.58s (± 0.34%)}	_{143.91s (± 0.39%)}	_~	_143.15s	_144.80s	_{p=0.378 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_267,560	_268,161	_{+601 (+ 0.22%)}	_~	_~	_{p=0.001 n=6}
_Types	_109,076	_109,363	_{+287 (+ 0.26%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{412,418k (± 0.02%)}	_{412,877k (± 0.01%)}	_{+459k (+ 0.11%)}	_412,812k	_412,918k	_{p=0.005 n=6}
_{Parse Time}	_{3.85s (± 0.45%)}	_{3.84s (± 0.55%)}	_~	_3.81s	_3.86s	_{p=0.368 n=6}
_{Bind Time}	_1.72s	_{1.71s (± 0.68%)}	_{-0.01s (- 0.68%)}	_1.69s	_1.72s	_{p=0.028 n=6}
_{Check Time}	_{16.88s (± 0.29%)}	_{16.88s (± 0.31%)}	_~	_16.80s	_16.93s	_{p=0.810 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{22.45s (± 0.23%)}	_{22.42s (± 0.29%)}	_~	_22.32s	_22.49s	_{p=0.470 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_511,803	_511,827	_{+24 (+ 0.00%)}	_~	_~	_{p=0.001 n=6}
_Types	_162,088	_162,115	_{+27 (+ 0.02%)}	_~	_~	_{p=0.001 n=6}
_{Memory used}	_{449,133k (± 0.06%)}	_{449,092k (± 0.08%)}	_~	_448,621k	_449,441k	_{p=0.936 n=6}
_{Parse Time}	_{3.17s (± 1.03%)}	_{3.17s (± 0.62%)}	_~	_3.14s	_3.20s	_{p=1.000 n=6}
_{Bind Time}	_{1.16s (± 0.44%)}	_{1.15s (± 1.30%)}	_~	_1.14s	_1.18s	_{p=0.113 n=6}
_{Check Time}	_{17.18s (± 0.35%)}	_{17.16s (± 0.48%)}	_~	_17.04s	_17.23s	_{p=0.936 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{21.51s (± 0.43%)}	_{21.48s (± 0.44%)}	_~	_21.35s	_21.61s	_{p=0.747 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Compiler-Unions - node (v18.15.0, x64)
angular-1 - node (v18.15.0, x64)
mui-docs - node (v18.15.0, x64)
self-build-src - node (v18.15.0, x64)
self-build-src-public-api - node (v18.15.0, x64)
self-compiler - node (v18.15.0, x64)
ts-pre-modules - node (v18.15.0, x64)
vscode - node (v18.15.0, x64)
webpack - node (v18.15.0, x64)
xstate-main - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

typescript-bot · 2024-07-25T05:57:41Z

@jakebailey Here are the results of running the top 400 repos with tsc comparing main and refs/pull/48228/merge:

Something interesting changed - please have a look.

Details

apollographql/apollo-client

2 of 12 projects failed to build with the old tsc and were ignored

tsconfig.json

error TS2345: Argument of type 'DocumentTransformCacheKey' is not assignable to parameter of type 'IArguments | any[]'.
- src/utilities/graphql/DocumentTransform.ts#L112

discordjs/discord.js

45 of 62 projects failed to build with the old tsc and were ignored

packages/formatters/tsconfig.json

error TS2345: Argument of type 'string | RecursiveArray<string>' is not assignable to parameter of type 'RecursiveArray<string>'.
- packages/formatters/src/formatters.ts#L547

packages/formatters/tsconfig.eslint.json

error TS2345: Argument of type 'string | RecursiveArray<string>' is not assignable to parameter of type 'RecursiveArray<string>'.
- packages/formatters/src/formatters.ts#L547

packages/formatters/tsconfig.docs.json

error TS2345: Argument of type 'string | RecursiveArray<string>' is not assignable to parameter of type 'RecursiveArray<string>'.
- packages/formatters/src/formatters.ts#L547

hexojs/hexo

tsconfig.json

error TS2339: Property 'push' does not exist on type 'string[] | (string & readonly string[])'.
- lib/theme/index.ts#L40

honojs/hono

5 of 6 projects failed to build with the old tsc and were ignored

tsconfig.json

error TS2345: Argument of type '(string | HtmlEscapedString) & readonly string[]' is not assignable to parameter of type '(string | number | HtmlEscapedString)[]'.
- src/jsx/jsx-dev-runtime.ts#L22

pubkey/rxdb

8 of 11 projects failed to build with the old tsc and were ignored

tsconfig.json

error TS2322: Type 'string | undefined' is not assignable to type 'string'.
- src/plugins/dev-mode/check-schema.ts#L446

config/tsconfig.types.json

error TS2322: Type 'string | undefined' is not assignable to type 'string'.
- src/plugins/dev-mode/check-schema.ts#L446

recharts/recharts

1 of 4 projects failed to build with the old tsc and were ignored

tsconfig.json

error TS2538: Type 'unknown' cannot be used as an index type.
- src/util/DataUtils.ts#L87
- src/util/DataUtils.ts#L88

storybook/tsconfig.json

error TS2538: Type 'unknown' cannot be used as an index type.
- src/util/DataUtils.ts#L87
- src/util/DataUtils.ts#L88

demo/tsconfig.json

error TS2538: Type 'unknown' cannot be used as an index type.
- src/util/DataUtils.ts#L87
- src/util/DataUtils.ts#L88

jablko and others added 2 commits March 11, 2022 14:17

isArray() preserve mutability and element type

ce7e3c8

Update Baselines and/or Applied Lint Fixes

8f90881

typescript-bot added the For Milestone Bug PRs that fix a bug with a specific milestone label Mar 11, 2022

This was referenced Mar 11, 2022

A second attempt at readonly array support persisting through isArray #42316

Closed

Array.isArray type narrows to any[] for ReadonlyArray<T> #17002

Open

sandersn assigned RyanCavanaugh Mar 21, 2022

sandersn requested review from DanielRosenwasser and RyanCavanaugh March 21, 2022 15:26

graphemecluster mentioned this pull request Aug 25, 2022

lib Fix Part 6/6 – Array.isArray #50454

Closed

bmish mentioned this pull request Dec 14, 2022

Enable type-aware linting bmish/eslint-doc-generator#345

Merged

Mifrill reviewed Nov 10, 2023

View reviewed changes

src/lib/es5.d.ts Show resolved Hide resolved

Mifrill reviewed Nov 10, 2023

View reviewed changes

tests/baselines/reference/destructuringParameterDeclaration4.errors.txt Outdated Show resolved Hide resolved

Merge branch 'main' into pr-48228

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isArray() preserve mutability and element type #48228

isArray() preserve mutability and element type #48228

jablko commented Mar 11, 2022

typescript-bot commented Mar 11, 2022

typescript-bot commented Mar 11, 2022

RyanCavanaugh commented Mar 11, 2022

SPGoding commented Jun 2, 2022 •

edited

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jakebailey commented Jul 25, 2024

typescript-bot commented Jul 25, 2024 •

edited

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typescript-bot commented Jul 25, 2024

typescript-bot commented Jul 25, 2024

effect

packages/schema/benchmark/tsconfig.json

tsconfig.json

tsconfig.build.json

tsconfig.base.json

typescript-bot commented Jul 25, 2024

tsc

typescript-bot commented Jul 25, 2024

apollographql/apollo-client

tsconfig.json

discordjs/discord.js

packages/formatters/tsconfig.json

packages/formatters/tsconfig.eslint.json

packages/formatters/tsconfig.docs.json

hexojs/hexo

tsconfig.json

honojs/hono

tsconfig.json

pubkey/rxdb

tsconfig.json

config/tsconfig.types.json

recharts/recharts

tsconfig.json

storybook/tsconfig.json

demo/tsconfig.json

isArray() preserve mutability and element type #48228

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isArray() preserve mutability and element type #48228

Conversation

jablko commented Mar 11, 2022

🩹 Proposed solution

⏯️ Playground link

🧑‍💻 Code

🙁 Actual behavior

🙂 Expected behavior

typescript-bot commented Mar 11, 2022

typescript-bot commented Mar 11, 2022

RyanCavanaugh commented Mar 11, 2022

SPGoding commented Jun 2, 2022 • edited Loading

jakebailey commented Jul 25, 2024

typescript-bot commented Jul 25, 2024 • edited Loading

typescript-bot commented Jul 25, 2024

typescript-bot commented Jul 25, 2024

typescript-bot commented Jul 25, 2024

tsc

typescript-bot commented Jul 25, 2024

SPGoding commented Jun 2, 2022 •

edited

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typescript-bot commented Jul 25, 2024 •

edited

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