Improvements to `strictSubtypeRelation` and `getNarrowedType` #52282

ahejlsberg · 2023-01-18T01:49:32Z

This PR fixes a number of inconsistencies related to the strict subtype relation and user defined type predicate narrowing. Specifically:

In the strict subtype relation, unknown is related to any but any is not related to unknown. Previously, the two were mutually related.
In the strict subtype relation, a non-fresh object type is not related to a another object type if the first type is missing an index signature. Previously, it was possible for such types to be mutually related.
In the subtype and strict subtype relations, given a signature S1 of the form (...args: A) => R, where A is any, any[], never, or never[], and R is any or unknown, and a signature S2 not of that form, S2 is related to S1 but S1 is not related to S2. Previously, it was possible for such signatures to be mutually related.
The assignment expression x = y is has the same type as y with any object literal freshness preserved. Previously, object literal freshness was stripped.
Narrowing by a user defined type predicate preserves the original type in the false branch for non-identical mutual subtypes.

The strict subtype relation primarily controls subtype reduction of union types. Subtype reduction occurs in control flow analysis and other situations that require determining a common supertype for multiple types. For example, given expressions a and b of type A and B, the element type of an array literal [a, b] is A if B is a subtype of A, B if A is a subtype of B, or A | B if neither is a subtype of the other. However, if A and B are mutual subtypes, the type chosen may ultimately depend on declaration order, which isn't desired. The goal of the strict subtype relation is to impose a stable ordering by eliminating mutual subtypes, and the first three rules above further that goal.

Fixes #50916.

ahejlsberg · 2023-01-18T01:51:15Z

@typescript-bot test this
@typescript-bot user test this inline
@typescript-bot run dt
@typescript-bot perf test faster
@typescript-bot test top100

typescript-bot · 2023-01-18T01:51:18Z

Heya @ahejlsberg, I've started to run the diff-based top-repos suite on this PR at 14985d4. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-01-18T01:51:18Z

Heya @ahejlsberg, I've started to run the parallelized Definitely Typed test suite on this PR at 14985d4. You can monitor the build here.

typescript-bot · 2023-01-18T01:51:18Z

Heya @ahejlsberg, I've started to run the diff-based user code test suite on this PR at 14985d4. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-01-18T01:51:18Z

Heya @ahejlsberg, I've started to run the abridged perf test suite on this PR at 14985d4. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-01-18T01:51:18Z

Heya @ahejlsberg, I've started to run the extended test suite on this PR at 14985d4. You can monitor the build here.

typescript-bot · 2023-01-18T02:04:13Z

@ahejlsberg Here are the results of running the user test suite comparing main and refs/pull/52282/merge:

Everything looks good!

typescript-bot · 2023-01-18T02:11:35Z

Heya @ahejlsberg, I've run the RWC suite on this PR - assuming you're on the TS core team, you can view the resulting diff here.

typescript-bot · 2023-01-18T02:33:20Z

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

Here they are:

Comparison Report - main..52282

_Metric	_main	₅₂₂₈₂	_Delta	_Best	_Worst
_{Angular - node (v16.17.1, x64)}
_{Memory used}	_{358,311k (± 0.01%)}	_{358,322k (± 0.01%)}	_{+11k (+ 0.00%)}	_358,263k	_358,361k
_{Parse Time}	_{4.10s (± 0.58%)}	_{4.12s (± 0.59%)}	_{+0.01s (+ 0.33%)}	_4.09s	_4.16s
_{Bind Time}	_{1.25s (± 0.35%)}	_{1.25s (± 0.45%)}	_{-0.00s (- 0.03%)}	_1.25s	_1.26s
_{Check Time}	_{9.49s (± 0.50%)}	_{9.49s (± 0.18%)}	_{-0.00s (- 0.02%)}	_9.47s	_9.51s
_{Emit Time}	_{7.96s (± 0.25%)}	_{7.94s (± 0.44%)}	_{-0.02s (- 0.22%)}	_7.90s	_8.00s
_{Total Time}	_{22.81s (± 0.20%)}	_{22.80s (± 0.18%)}	_{-0.00s (- 0.01%)}	_22.72s	_22.83s
_{Compiler-Unions - node (v16.17.1, x64)}
_{Memory used}	_{195,555k (± 0.96%)}	_{191,823k (± 0.03%)}	_{-3,732k (- 1.91%)}	_191,735k	_191,901k
_{Parse Time}	_{1.80s (± 1.25%)}	_{1.81s (± 0.39%)}	_{+0.01s (+ 0.31%)}	_1.80s	_1.82s
_{Bind Time}	_{0.85s (± 0.61%)}	_{0.85s (± 0.72%)}	_{+0.00s (+ 0.03%)}	_0.84s	_0.86s
_{Check Time}	_{10.24s (± 0.56%)}	_{10.09s (± 0.99%)}	_{-0.15s (- 1.44%)}	_9.94s	_10.20s
_{Emit Time}	_{3.13s (± 5.36%)}	_{3.06s (± 2.08%)}	_{-0.07s (- 2.26%)}	_3.01s	_3.18s
_{Total Time}	_{16.02s (± 1.05%)}	_{15.81s (± 0.60%)}	_{-0.21s (- 1.33%)}	_15.64s	_15.91s
_{Monaco - node (v16.17.1, x64)}
_{Memory used}	_{345,118k (± 0.01%)}	_{345,147k (± 0.01%)}	_{+29k (+ 0.01%)}	_345,115k	_345,172k
_{Parse Time}	_{3.10s (± 1.05%)}	_{3.10s (± 0.76%)}	_{+0.00s (+ 0.01%)}	_3.08s	_3.14s
_{Bind Time}	_{1.11s (± 0.87%)}	_{1.11s (± 0.79%)}	_{-0.00s (- 0.38%)}	_1.10s	_1.12s
_{Check Time}	_{7.87s (± 0.09%)}	_{7.93s (± 1.08%)}	_{+0.05s (+ 0.66%)}	_7.85s	_8.09s
_{Emit Time}	_{4.57s (± 1.09%)}	_{4.57s (± 2.05%)}	_{+0.01s (+ 0.14%)}	_4.50s	_4.76s
_{Total Time}	_{16.66s (± 0.39%)}	_{16.71s (± 1.09%)}	_{+0.05s (+ 0.32%)}	_16.56s	_17.07s
_{TFS - node (v16.17.1, x64)}
_{Memory used}	_{299,919k (± 0.01%)}	_{299,918k (± 0.00%)}	_{-1k (- 0.00%)}	_299,911k	_299,924k
_{Parse Time}	_{2.43s (± 1.35%)}	_{2.42s (± 1.01%)}	_{-0.01s (- 0.41%)}	_2.40s	_2.46s
_{Bind Time}	_{1.26s (± 1.06%)}	_{1.26s (± 0.62%)}	_{+0.00s (+ 0.26%)}	_1.25s	_1.27s
_{Check Time}	_{7.41s (± 0.40%)}	_{7.44s (± 0.43%)}	_{+0.03s (+ 0.38%)}	_7.40s	_7.49s
_{Emit Time}	_{4.23s (± 0.38%)}	_{4.25s (± 0.52%)}	_{+0.01s (+ 0.31%)}	_4.21s	_4.27s
_{Total Time}	_{15.34s (± 0.49%)}	_{15.38s (± 0.31%)}	_{+0.03s (+ 0.23%)}	_15.31s	_15.45s
_{material-ui - node (v16.17.1, x64)}
_{Memory used}	_{475,709k (± 0.00%)}	_{475,705k (± 0.00%)}	_{-4k (- 0.00%)}	_475,666k	_475,734k
_{Parse Time}	_{3.65s (± 0.39%)}	_{3.66s (± 0.26%)}	_{+0.01s (+ 0.25%)}	_3.65s	_3.68s
_{Bind Time}	_{1.01s (± 0.51%)}	_{1.01s (± 0.50%)}	_{+0.00s (+ 0.40%)}	_1.00s	_1.02s
_{Check Time}	_{17.86s (± 0.22%)}	_{18.05s (± 0.69%)}	_{+0.18s (+ 1.01%)}	_17.90s	_18.26s
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_{0.00s ( NaN%)}	_0.00s	_0.00s
_{Total Time}	_{22.53s (± 0.17%)}	_{22.72s (± 0.52%)}	_{+0.19s (+ 0.85%)}	_22.57s	_22.92s
_{xstate - node (v16.17.1, x64)}
_{Memory used}	_{543,991k (± 0.02%)}	_{544,002k (± 0.01%)}	_{+11k (+ 0.00%)}	_543,961k	_544,099k
_{Parse Time}	_{4.57s (± 0.37%)}	_{4.60s (± 0.72%)}	_{+0.03s (+ 0.65%)}	_4.57s	_4.66s
_{Bind Time}	_{1.79s (± 0.38%)}	_{1.80s (± 0.18%)}	_{+0.00s (+ 0.19%)}	_1.79s	_1.80s
_{Check Time}	_{2.93s (± 0.44%)}	_{2.93s (± 0.54%)}	_{+0.00s (+ 0.04%)}	_2.91s	_2.95s
_{Emit Time}	_{0.08s (± 6.09%)}	_{0.08s (± 6.08%)}	_{+0.00s (+ 0.10%)}	_0.08s	_0.09s
_{Total Time}	_{9.38s (± 0.20%)}	_{9.42s (± 0.26%)}	_{+0.03s (+ 0.37%)}	_9.39s	_9.45s

System

_{Machine Name}	_ts-ci-ubuntu
_Platform	_{linux 5.4.0-135-generic}
_Architecture	_x64
_{Available Memory}	_{16 GB}
_{Available Memory}	_{15 GB}
_CPUs	_{4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz}

Hosts

node (v16.17.1, x64)

Scenarios

Angular - node (v16.17.1, x64)
Compiler-Unions - node (v16.17.1, x64)
Monaco - node (v16.17.1, x64)
TFS - node (v16.17.1, x64)
material-ui - node (v16.17.1, x64)
xstate - node (v16.17.1, x64)

_Benchmark	_Name	_Iterations
_Current	₅₂₂₈₂	₆
_Baseline	_main	₆

Developer Information:

Download Benchmark

typescript-bot · 2023-01-18T03:36:02Z

@ahejlsberg Here are the results of running the top-repos suite comparing main and refs/pull/52282/merge:

Something interesting changed - please have a look.

Details

marmelab/react-admin

22 of 23 projects failed to build with the old tsc and were ignored

packages/ra-core/tsconfig.json

error TS2604: JSX element type 'Create' does not have any construct or call signatures.
- packages/ra-core/src/core/Resource.tsx#L17
error TS2604: JSX element type 'Show' does not have any construct or call signatures.
- packages/ra-core/src/core/Resource.tsx#L23
error TS2604: JSX element type 'Edit' does not have any construct or call signatures.
- packages/ra-core/src/core/Resource.tsx#L29
error TS2604: JSX element type 'List' does not have any construct or call signatures.
- packages/ra-core/src/core/Resource.tsx#L35

ReactiveX/rxjs

8 of 13 projects failed to build with the old tsc and were ignored

src/tsconfig.cjs.spec.json

error TS2339: Property 'next' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L220
- src/internal/Subscriber.ts#L220
error TS2339: Property 'error' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L221
- src/internal/Subscriber.ts#L221
error TS2339: Property 'complete' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L222
- src/internal/Subscriber.ts#L222
error TS2322: Type 'Partial<Observer<T>> | ((value: T) => void)' is not assignable to type 'Partial<Observer<T>>'.
- src/internal/Subscriber.ts#L226
error TS2339: Property 'unsubscribe' does not exist on type 'Unsubscribable | (() => void)'.
- src/internal/Subscription.ts#L214
error TS2339: Property 'subscribe' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L121
error TS2339: Property 'next' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L127
error TS2339: Property 'complete' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L132
error TS2339: Property 'error' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L137
error TS2339: Property 'unsubscribe' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L142
error TS2339: Property 'finalize' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L144

src/tsconfig.esm5.rollup.json

error TS2339: Property 'next' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L220
- src/internal/Subscriber.ts#L220
error TS2339: Property 'error' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L221
- src/internal/Subscriber.ts#L221
error TS2339: Property 'complete' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L222
- src/internal/Subscriber.ts#L222
error TS2322: Type 'Partial<Observer<T>> | ((value: T) => void)' is not assignable to type 'Partial<Observer<T>>'.
- src/internal/Subscriber.ts#L226
error TS2339: Property 'unsubscribe' does not exist on type 'Unsubscribable | (() => void)'.
- src/internal/Subscription.ts#L214
error TS2339: Property 'subscribe' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L121
error TS2339: Property 'next' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L127
error TS2339: Property 'complete' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L132
error TS2339: Property 'error' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L137
error TS2339: Property 'unsubscribe' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L142
error TS2339: Property 'finalize' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L144

src/tsconfig.types.json

error TS2339: Property 'unsubscribe' does not exist on type 'Unsubscribable | (() => void)'.
- src/internal/Subscription.ts#L214 in src/tsconfig.types.json
error TS2339: Property 'next' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L220 in src/tsconfig.types.json
- src/internal/Subscriber.ts#L220 in src/tsconfig.types.json
error TS2339: Property 'error' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L221 in src/tsconfig.types.json
- src/internal/Subscriber.ts#L221 in src/tsconfig.types.json
error TS2339: Property 'complete' does not exist on type 'Partial<Observer<T>> | ((value: T) => void)'.
- src/internal/Subscriber.ts#L222 in src/tsconfig.types.json
- src/internal/Subscriber.ts#L222 in src/tsconfig.types.json
error TS2322: Type 'Partial<Observer<T>> | ((value: T) => void)' is not assignable to type 'Partial<Observer<T>>'.
- src/internal/Subscriber.ts#L226 in src/tsconfig.types.json
error TS2339: Property 'subscribe' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L121 in src/tsconfig.types.json
error TS2339: Property 'next' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L127 in src/tsconfig.types.json
error TS2339: Property 'complete' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L132 in src/tsconfig.types.json
error TS2339: Property 'error' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L137 in src/tsconfig.types.json
error TS2339: Property 'unsubscribe' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L142 in src/tsconfig.types.json
error TS2339: Property 'finalize' does not exist on type 'Partial<TapObserver<T>> | ((value: T) => void)'.
- src/internal/operators/tap.ts#L144 in src/tsconfig.types.json

vuejs/vue

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

tsconfig.json

error TS2339: Property 'get' does not exist on type 'Record<string, any> | (() => any)'.
- src/core/instance/state.ts#L232
- src/core/instance/state.ts#L235
error TS2339: Property 'cache' does not exist on type 'Record<string, any> | (() => any)'.
- src/core/instance/state.ts#L233
error TS2339: Property 'set' does not exist on type 'Record<string, any> | (() => any)'.
- src/core/instance/state.ts#L237
error TS2345: Argument of type 'string | (() => any)' is not assignable to parameter of type 'string'.
- src/core/observer/watcher.ts#L115
error TS2578: Unused '@ts-expect-error' directive.
- src/core/vdom/create-component.ts#L238
error TS2339: Property 'slot' does not exist on type 'VNodeData | {}'.
- src/core/vdom/create-functional-component.ts#L171
error TS2339: Property 'transition' does not exist on type 'VNodeData | {}'.
- src/platforms/web/runtime/components/transition-group.ts#L72
- src/platforms/web/runtime/components/transition.ts#L153
error TS2339: Property 'loader' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L39
error TS2339: Property 'loadingComponent' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L40
error TS2339: Property 'errorComponent' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L41
error TS2339: Property 'delay' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L42
error TS2339: Property 'timeout' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L43
error TS2339: Property 'suspensible' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L44
error TS2339: Property 'onError' does not exist on type 'AsyncComponentOptions | (() => any)'.
- src/v3/apiAsyncComponent.ts#L45

ahejlsberg · 2023-01-19T19:20:31Z

@typescript-bot test this
@typescript-bot user test this inline
@typescript-bot run dt
@typescript-bot perf test faster
@typescript-bot test top100

typescript-bot · 2023-01-19T19:20:35Z

Heya @ahejlsberg, I've started to run the diff-based user code test suite on this PR at d7a80c4. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-01-19T19:20:35Z

Heya @ahejlsberg, I've started to run the parallelized Definitely Typed test suite on this PR at d7a80c4. You can monitor the build here.

typescript-bot · 2023-01-19T19:20:35Z

Heya @ahejlsberg, I've started to run the abridged perf test suite on this PR at d7a80c4. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-01-19T19:20:35Z

Heya @ahejlsberg, I've started to run the extended test suite on this PR at d7a80c4. You can monitor the build here.

typescript-bot · 2023-01-19T19:20:35Z

Heya @ahejlsberg, I've started to run the diff-based top-repos suite on this PR at d7a80c4. You can monitor the build here.

Update: The results are in!

typescript-bot · 2023-01-19T19:33:48Z

@ahejlsberg Here are the results of running the user test suite comparing main and refs/pull/52282/merge:

Everything looks good!

typescript-bot · 2023-01-19T19:37:09Z

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

Here they are:

Comparison Report - main..52282

_Metric	_main	₅₂₂₈₂	_Delta	_Best	_Worst
_{Angular - node (v16.17.1, x64)}
_{Memory used}	_{358,348k (± 0.01%)}	_{358,145k (± 0.01%)}	_{-203k (- 0.06%)}	_358,095k	_358,205k
_{Parse Time}	_{4.10s (± 0.43%)}	_{4.09s (± 0.25%)}	_{-0.02s (- 0.37%)}	_4.07s	_4.10s
_{Bind Time}	_{1.25s (± 0.39%)}	_{1.25s (± 0.71%)}	_{+0.00s (+ 0.03%)}	_1.24s	_1.27s
_{Check Time}	_{9.47s (± 0.41%)}	_{9.51s (± 0.38%)}	_{+0.04s (+ 0.42%)}	_9.46s	_9.56s
_{Emit Time}	_{7.97s (± 0.26%)}	_{7.97s (± 0.68%)}	_{-0.00s (- 0.05%)}	_7.92s	_8.06s
_{Total Time}	_{22.80s (± 0.15%)}	_{22.82s (± 0.37%)}	_{+0.03s (+ 0.11%)}	_22.73s	_22.96s
_{Compiler-Unions - node (v16.17.1, x64)}
_{Memory used}	_{193,926k (± 0.03%)}	_{192,283k (± 0.73%)}	_{-1,643k (- 0.85%)}	_191,608k	_195,141k
_{Parse Time}	_{1.80s (± 1.18%)}	_{1.81s (± 0.80%)}	_{+0.02s (+ 0.93%)}	_1.79s	_1.84s
_{Bind Time}	_{0.85s (± 0.59%)}	_{0.85s (± 0.56%)}	_{-0.00s (- 0.00%)}	_0.85s	_0.86s
_{Check Time}	_{10.27s (± 0.42%)}	_{10.09s (± 0.72%)}	_{-0.17s (- 1.70%)}	_10.02s	_10.19s
_{Emit Time}	_{3.03s (± 1.10%)}	_{3.04s (± 0.43%)}	_{+0.00s (+ 0.05%)}	_3.02s	_3.05s
_{Total Time}	_{15.95s (± 0.29%)}	_{15.79s (± 0.39%)}	_{-0.16s (- 1.03%)}	_15.72s	_15.87s
_{Monaco - node (v16.17.1, x64)}
_{Memory used}	_{345,126k (± 0.01%)}	_{345,149k (± 0.02%)}	_{+23k (+ 0.01%)}	_345,068k	_345,198k
_{Parse Time}	_{3.10s (± 1.17%)}	_{3.10s (± 0.53%)}	_{+0.00s (+ 0.05%)}	_3.08s	_3.13s
_{Bind Time}	_{1.11s (± 0.66%)}	_{1.11s (± 1.28%)}	_{+0.01s (+ 0.57%)}	_1.09s	_1.13s
_{Check Time}	_{7.88s (± 0.32%)}	_{7.91s (± 0.56%)}	_{+0.03s (+ 0.42%)}	_7.84s	_7.95s
_{Emit Time}	_{4.53s (± 0.75%)}	_{4.53s (± 0.80%)}	_{+0.01s (+ 0.16%)}	_4.49s	_4.60s
_{Total Time}	_{16.60s (± 0.46%)}	_{16.65s (± 0.41%)}	_{+0.05s (+ 0.29%)}	_16.56s	_16.76s
_{TFS - node (v16.17.1, x64)}
_{Memory used}	_{299,929k (± 0.00%)}	_{299,939k (± 0.00%)}	_{+11k (+ 0.00%)}	_299,922k	_299,954k
_{Parse Time}	_{2.43s (± 0.88%)}	_{2.44s (± 0.84%)}	_{+0.01s (+ 0.37%)}	_2.40s	_2.46s
_{Bind Time}	_{1.27s (± 0.62%)}	_{1.27s (± 0.68%)}	_{-0.00s (- 0.03%)}	_1.26s	_1.28s
_{Check Time}	_{7.42s (± 0.36%)}	_{7.44s (± 0.42%)}	_{+0.02s (+ 0.28%)}	_7.41s	_7.48s
_{Emit Time}	_{4.25s (± 1.22%)}	_{4.26s (± 0.57%)}	_{+0.01s (+ 0.14%)}	_4.24s	_4.29s
_{Total Time}	_{15.37s (± 0.41%)}	_{15.40s (± 0.26%)}	_{+0.04s (+ 0.24%)}	_15.35s	_15.45s
_{material-ui - node (v16.17.1, x64)}
_{Memory used}	_{475,698k (± 0.01%)}	_{475,695k (± 0.00%)}	_{-3k (- 0.00%)}	_475,684k	_475,711k
_{Parse Time}	_{3.66s (± 0.27%)}	_{3.66s (± 0.29%)}	_{+0.00s (+ 0.04%)}	_3.65s	_3.68s
_{Bind Time}	_{1.02s (± 0.40%)}	_{1.02s (± 0.77%)}	_{-0.00s (- 0.03%)}	_1.00s	_1.03s
_{Check Time}	_{17.92s (± 0.80%)}	_{17.90s (± 0.44%)}	_{-0.02s (- 0.13%)}	_17.82s	_18.01s
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_{0.00s ( NaN%)}	_0.00s	_0.00s
_{Total Time}	_{22.60s (± 0.66%)}	_{22.58s (± 0.38%)}	_{-0.02s (- 0.10%)}	_22.48s	_22.70s
_{xstate - node (v16.17.1, x64)}
_{Memory used}	_{543,932k (± 0.01%)}	_{543,978k (± 0.01%)}	_{+46k (+ 0.01%)}	_543,924k	_544,042k
_{Parse Time}	_{4.57s (± 0.44%)}	_{4.58s (± 0.44%)}	_{+0.02s (+ 0.33%)}	_4.55s	_4.60s
_{Bind Time}	_{1.79s (± 0.86%)}	_{1.79s (± 0.30%)}	_{+0.00s (+ 0.25%)}	_1.79s	_1.80s
_{Check Time}	_{2.94s (± 0.73%)}	_{2.93s (± 0.75%)}	_{-0.01s (- 0.31%)}	_2.90s	_2.96s
_{Emit Time}	_{0.08s (± 6.19%)}	_{0.08s (± 6.44%)}	_{+0.00s (+ 1.97%)}	_0.08s	_0.09s
_{Total Time}	_{9.39s (± 0.30%)}	_{9.39s (± 0.22%)}	_{+0.00s (+ 0.02%)}	_9.37s	_9.43s

System

_{Machine Name}	_ts-ci-ubuntu
_Platform	_{linux 5.4.0-135-generic}
_Architecture	_x64
_{Available Memory}	_{16 GB}
_{Available Memory}	_{15 GB}
_CPUs	_{4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz}

Hosts

node (v16.17.1, x64)

Scenarios

Angular - node (v16.17.1, x64)
Compiler-Unions - node (v16.17.1, x64)
Monaco - node (v16.17.1, x64)
TFS - node (v16.17.1, x64)
material-ui - node (v16.17.1, x64)
xstate - node (v16.17.1, x64)

_Benchmark	_Name	_Iterations
_Current	₅₂₂₈₂	₆
_Baseline	_main	₆

Developer Information:

Download Benchmark

# Conflicts: # src/compiler/checker.ts

DanielRosenwasser · 2023-02-06T22:23:29Z

@typescript-bot top200

jakebailey · 2023-02-06T22:29:44Z

Before we approve/merge this, can we make sure that cases like those listed in various replies to #48840 (and #52387) are all tested to be working with their desired behaviors?

ahejlsberg · 2023-02-07T00:02:56Z

@jakebailey This PR doesn't change anything with regards to #48840 and #52387.

ahejlsberg · 2023-02-07T00:03:24Z

@typescript-bot test top200

ahejlsberg · 2023-02-07T00:06:14Z

@DanielRosenwasser I don't think there's such a thing as test200 in typescript-bot. The results of test100 are here and, as we discussed, are acceptable.

jakebailey · 2023-02-07T00:11:26Z

@jakebailey This PR doesn't change anything with regards to #48840 and #52387.

I guess I shouldn't have mentioned the PR as I think it drew the focus away from what I actually wanted checked. I meant that the issue thread (#48840) has some discussion as to what constitutes a top-function-type, which is changing in this PR via isTopSignature.

I'll just pack this PR and test it.

@typescript-bot pack this

typescript-bot · 2023-02-07T00:11:29Z

Heya @jakebailey, I've started to run the tarball bundle task on this PR at e249498. You can monitor the build here.

typescript-bot · 2023-02-07T00:13:35Z

Hey @jakebailey, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/145789/artifacts?artifactName=tgz&fileId=6D0BA089D05A85084C1DC8BBF2F77939D48C21AA802E40F6C6C93CD6D630F5C802&fileName=/typescript-5.0.0-insiders.20230207.tgz"
    }
}

and then running npm install.

There is also a playground for this build and an npm module you can use via "typescript": "npm:@typescript-deploys/[email protected]".;

jakebailey · 2023-02-07T00:44:26Z

Okay, the things I wanted to test appear to work fine, or at least have not changed behavior from 4.9 anyhow.

DanielRosenwasser

Would you be able to add tests that demonstrate the ordering among supertypey functions?

type A = (...args: any) => unknown;
type B = (...args: any[]) => unknown;
type C = (...args: never) => unknown;
type D = (...args: never[]) => unknown;
type E = () => unknown;

type FnTypes = A | B | C | D | E;

declare function isSomeFunc<T>(x: any): x is T;

function checkA(f: FnTypes) {
    if (isSomeFunc<A>(f)) {
        f
    }
    else {
        f
    }
    f
}

function checkB(f: FnTypes) {
    if (isSomeFunc<B>(f)) {
        f
    }
    else {
        f
    }
    f
}

function checkC(f: FnTypes) {
    if (isSomeFunc<C>(f)) {
        f
    }
    else {
        f
    }
    f
}

function checkD(f: FnTypes) {
    if (isSomeFunc<D>(f)) {
        f
    }
    else {
        f
    }
    f
}

function checkE(f: FnTypes) {
    if (isSomeFunc<E>(f)) {
        f
    }
    else {
        f
    }
    f
}

ahejlsberg · 2023-02-14T19:42:05Z

@DanielRosenwasser More tests added.

ahejlsberg added 3 commits January 17, 2023 17:26

Improvements to strictSubtypeRelation and getNarrowedType

211179f

Accept new baselines

d44732a

Add tests

14985d4

typescript-bot assigned ahejlsberg Jan 18, 2023

typescript-bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Jan 18, 2023

ahejlsberg changed the title ~~Fix50916~~ Improvements to strictSubtypeRelation and getNarrowedType Jan 18, 2023

ahejlsberg added 4 commits January 18, 2023 17:31

Keep object literal freshness in type of assignment expression

95b1a3e

Ensure (...args: any[]) => any is never subtype of other signatures

1e429d7

Keep false branch logic for instanceof in getNarrowedType

7d8fdc8

Broaden rule that ensures { [x: string]: xxx } <: {} and not vice-versa

d7a80c4

Accept new baselines

ed1ee19

jakebailey mentioned this pull request Feb 1, 2023

Fixed an issue with top function type being callable with no arguments #52387

Merged

Merge branch 'main' into fix50916

e249498

# Conflicts: # src/compiler/checker.ts

DanielRosenwasser requested changes Feb 8, 2023

View reviewed changes

Add more tests and remove duplicates

caf42f0

typescript-bot added For Milestone Bug PRs that fix a bug with a specific milestone and removed For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Feb 14, 2023

DanielRosenwasser approved these changes Feb 14, 2023

View reviewed changes

ahejlsberg merged commit 84b8483 into main Feb 14, 2023

ahejlsberg deleted the fix50916 branch February 14, 2023 20:12

This was referenced Feb 17, 2023

Update lodash tests for TS 5.0 DefinitelyTyped/DefinitelyTyped#64406

Merged

Improvement to getNarrowedType changes lodash's isArray #52827

Closed

MichaelMitchell-at mentioned this pull request Mar 3, 2023

Check for strict subtypes and then regular subtypes in getNarrowedType #52984

Merged

DanielRosenwasser mentioned this pull request Mar 3, 2023

Design Meeting Notes, 3/3/2023 #53083

Closed

RyanCavanaugh mentioned this pull request Mar 14, 2023

Broken type inference with a typeguard in a if statement #53216

Closed

Andarist mentioned this pull request Mar 19, 2023

5.0: Narrowing from type-guards ignored when constructing JSX call (2604) #53178

Closed

jakebailey mentioned this pull request May 19, 2023

Explain use of never[] as most generic function argument microsoft/TypeScript-Website#2714

Open

RyanCavanaugh mentioned this pull request Nov 13, 2023

Inconsistency when assigning a never type parameter to any[] type parameter #56379

Closed

eps1lon mentioned this pull request Mar 21, 2024

type guard narrowing to a type with type with any in type parameters replaces any with unknown #57892

Closed

RyanCavanaugh mentioned this pull request Jun 26, 2024

Suspected breaking change with pushing and assigning a 'derived' value into a 'base' array #59016

Open

microsoft locked as resolved and limited conversation to collaborators Oct 22, 2025

Improvements to strictSubtypeRelation and getNarrowedType #52282

Improvements to strictSubtypeRelation and getNarrowedType #52282

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Improvements to `strictSubtypeRelation` and `getNarrowedType` #52282

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