More complete check in isConstTypeVariable

[ahejlsberg]

This PR improves the logic introduced in #51865 for determining whether a contextual type implies a const context. With this PR, a contextual type implies a const context when the type is

• a type parameter that includes a const modifier,
• a union type with at least one constituent type that implies a const context,
• an indexed access type T[K] where T implies a const context,
• a conditional type A extends B ? X : Y where X or Y imply a const context, or
• a tuple type containing at least one variadic element ...T where T implies a const context.

Fixes #53307.

[ahejlsberg]

@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]

Heya @ahejlsberg, I've started to run the abridged perf test suite on this PR at 9eb3d5a. You can monitor the build here.

Update: The results are in!

[typescript-bot]

Heya @ahejlsberg, I've started to run the extended test suite on this PR at 9eb3d5a. You can monitor the build here.

[typescript-bot]

Heya @ahejlsberg, I've started to run the diff-based user code test suite on this PR at 9eb3d5a. You can monitor the build here.

Update: The results are in!

[typescript-bot]

Heya @ahejlsberg, I've started to run the parallelized Definitely Typed test suite on this PR at 9eb3d5a. You can monitor the build here.

Update: The results are in!

[typescript-bot]

Heya @ahejlsberg, I've started to run the diff-based top-repos suite on this PR at 9eb3d5a. You can monitor the build here.

Update: The results are in!

[typescript-bot]

@ahejlsberg Here are the results of running the user test suite comparing main and refs/pull/53341/merge:

Everything looks good!

[typescript-bot]

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

Here they are:

Comparison Report - main..53341

Metric	main	53341	Delta	Best	Worst	p-value
Angular - node (v16.17.1, x64)
Memory used	360,896k (± 0.01%)	360,891k (± 0.01%)	~	360,856k	360,922k	p=0.936 n=6
Parse Time	3.52s (± 0.69%)	3.53s (± 0.90%)	~	3.48s	3.57s	p=0.871 n=6
Bind Time	1.18s (± 0.69%)	1.18s (± 0.44%)	~	1.18s	1.19s	p=0.929 n=6
Check Time	9.46s (± 0.52%)	9.47s (± 0.53%)	~	9.42s	9.56s	p=0.746 n=6
Emit Time	7.93s (± 0.68%)	7.89s (± 0.41%)	~	7.84s	7.92s	p=0.195 n=6
Total Time	22.10s (± 0.38%)	22.07s (± 0.44%)	~	21.97s	22.23s	p=0.630 n=6
Compiler-Unions - node (v16.17.1, x64)
Memory used	192,531k (± 0.04%)	192,548k (± 0.03%)	~	192,460k	192,633k	p=0.810 n=6
Parse Time	1.57s (± 1.64%)	1.58s (± 0.93%)	~	1.56s	1.60s	p=0.870 n=6
Bind Time	0.82s (± 0.77%)	0.82s (± 0.50%)	~	0.81s	0.82s	p=0.673 n=6
Check Time	10.08s (± 0.62%)	10.05s (± 0.68%)	~	10.01s	10.19s	p=0.574 n=6
Emit Time	2.99s (± 0.63%)	2.98s (± 0.68%)	~	2.95s	3.01s	p=0.411 n=6
Total Time	15.47s (± 0.30%)	15.43s (± 0.48%)	~	15.38s	15.58s	p=0.127 n=6
Monaco - node (v16.17.1, x64)
Memory used	345,434k (± 0.01%)	345,439k (± 0.01%)	~	345,412k	345,485k	p=1.000 n=6
Parse Time	2.72s (± 0.36%)	2.72s (± 0.36%)	~	2.71s	2.74s	p=1.000 n=6
Bind Time	1.09s (± 0.50%)	1.08s (± 0.97%)	~	1.07s	1.10s	p=1.000 n=6
Check Time	7.66s (± 0.32%)	7.66s (± 0.48%)	~	7.62s	7.72s	p=0.872 n=6
Emit Time	4.42s (± 0.57%)	4.43s (± 0.67%)	~	4.40s	4.48s	p=0.627 n=6
Total Time	15.89s (± 0.19%)	15.90s (± 0.44%)	~	15.82s	16.03s	p=0.624 n=6
TFS - node (v16.17.1, x64)
Memory used	299,792k (± 0.01%)	299,789k (± 0.01%)	~	299,738k	299,852k	p=0.748 n=6
Parse Time	2.17s (± 0.48%)	2.17s (± 0.48%)	~	2.16s	2.19s	p=0.160 n=6
Bind Time	1.24s (± 0.88%)	1.24s (± 0.97%)	~	1.23s	1.26s	p=0.739 n=6
Check Time	7.17s (± 0.57%)	7.18s (± 0.30%)	~	7.15s	7.21s	p=0.872 n=6
Emit Time	4.31s (± 0.70%)	4.36s (± 0.45%)	+0.05s (+ 1.16%)	4.32s	4.37s	p=0.019 n=6
Total Time	14.88s (± 0.33%)	14.95s (± 0.23%)	+0.07s (+ 0.50%)	14.89s	14.99s	p=0.029 n=6
material-ui - node (v16.17.1, x64)
Memory used	477,460k (± 0.02%)	477,484k (± 0.01%)	~	477,419k	477,560k	p=0.688 n=6
Parse Time	3.21s (± 0.36%)	3.23s (± 0.41%)	~	3.21s	3.24s	p=0.077 n=6
Bind Time	0.95s (± 0.54%)	0.96s (± 0.54%)	~	0.95s	0.96s	p=0.311 n=6
Check Time	17.96s (± 0.49%)	17.97s (± 0.51%)	~	17.87s	18.11s	p=0.873 n=6
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	~	0.00s	0.00s	p=1.000 n=6
Total Time	22.12s (± 0.45%)	22.16s (± 0.43%)	~	22.04s	22.30s	p=0.521 n=6
xstate - node (v16.17.1, x64)
Memory used	550,802k (± 0.02%)	550,748k (± 0.02%)	~	550,639k	550,966k	p=0.378 n=6
Parse Time	3.94s (± 0.35%)	3.94s (± 0.58%)	~	3.90s	3.97s	p=0.517 n=6
Bind Time	1.80s (± 0.30%)	1.79s (± 0.77%)	~	1.76s	1.80s	p=0.138 n=6
Check Time	3.03s (± 0.39%)	3.03s (± 0.88%)	~	3.00s	3.07s	p=1.000 n=6
Emit Time	0.09s (± 0.00%)	0.09s (± 0.00%)	~	0.09s	0.09s	p=1.000 n=6
Total Time	8.86s (± 0.27%)	8.85s (± 0.25%)	~	8.82s	8.88s	p=0.746 n=6

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	53341	6
Baseline	main	6

Developer Information:

Download Benchmark

[typescript-bot]

@ahejlsberg Here are the results of running the top-repos suite comparing main and refs/pull/53341/merge:

Everything looks good!

[typescript-bot]

Hey @ahejlsberg, the results of running the DT tests are ready.
Everything looks the same!
You can check the log here.

[ahejlsberg]

Tests and performance all look good.

[sandersn]

@ahejlsberg Is this ready to merge now?