Mark all unreachable executable statements in cases and source files

[Andarist]

fixes #55562

[typescript-bot]

Looks like you're introducing a change to the public API surface area. If this includes breaking changes, please document them on our wiki's API Breaking Changes page.

Also, please make sure @DanielRosenwasser and @RyanCavanaugh are aware of the changes, just as a heads up.

[andrewbranch]

@typescript-bot perf test this
@typescript-bot test top100

[typescript-bot]

Heya @andrewbranch, I've started to run the diff-based top-repos suite on this PR at ea33899. You can monitor the build here.

Update: The results are in!

[typescript-bot]

Heya @andrewbranch, I've started to run the regular perf test suite on this PR at ea33899. You can monitor the build here.

Update: The results are in!

[typescript-bot]

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

Here they are:

Compiler

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
Angular - node (v16.17.1, x64)
Memory used	300,266k (± 0.00%)	300,291k (± 0.01%)	+25k (+ 0.01%)	300,270k	300,305k	p=0.013 n=6
Parse Time	3.01s (± 0.25%)	3.01s (± 0.14%)	~	3.01s	3.02s	p=0.389 n=6
Bind Time	0.93s (± 0.00%)	0.93s (± 0.00%)	~	0.93s	0.93s	p=1.000 n=6
Check Time	9.33s (± 0.16%)	9.34s (± 0.37%)	~	9.30s	9.39s	p=0.746 n=6
Emit Time	7.62s (± 0.30%)	7.64s (± 0.42%)	~	7.58s	7.67s	p=0.126 n=6
Total Time	20.90s (± 0.11%)	20.92s (± 0.15%)	~	20.89s	20.98s	p=0.124 n=6
Compiler-Unions - node (v16.17.1, x64)
Memory used	193,951k (± 0.02%)	194,494k (± 0.66%)	~	193,879k	197,125k	p=0.128 n=6
Parse Time	1.58s (± 0.26%)	1.58s (± 0.26%)	~	1.58s	1.59s	p=1.000 n=6
Bind Time	0.80s (± 0.51%)	0.80s (± 0.69%)	~	0.79s	0.80s	p=0.282 n=6
Check Time	9.96s (± 0.23%)	9.92s (± 0.44%)	~	9.86s	9.98s	p=0.195 n=6
Emit Time	2.75s (± 0.50%)	2.74s (± 0.50%)	~	2.72s	2.76s	p=0.217 n=6
Total Time	15.09s (± 0.09%)	15.04s (± 0.39%)	~	14.96s	15.11s	p=0.227 n=6
Monaco - node (v16.17.1, x64)
Memory used	347,207k (± 0.00%)	347,181k (± 0.01%)	~	347,106k	347,217k	p=0.873 n=6
Parse Time	2.69s (± 0.28%)	2.69s (± 0.15%)	~	2.68s	2.69s	p=1.000 n=6
Bind Time	0.99s (± 0.00%)	0.99s (± 0.00%)	~	0.99s	0.99s	p=1.000 n=6
Check Time	7.94s (± 0.22%)	7.95s (± 0.31%)	~	7.92s	7.99s	p=0.746 n=6
Emit Time	4.27s (± 0.30%)	4.27s (± 0.37%)	~	4.26s	4.30s	p=1.000 n=6
Total Time	15.89s (± 0.19%)	15.90s (± 0.25%)	~	15.85s	15.94s	p=1.000 n=6
TFS - node (v16.17.1, x64)
Memory used	301,188k (± 0.00%)	301,169k (± 0.01%)	~	301,147k	301,183k	p=0.109 n=6
Parse Time	2.17s (± 0.45%)	2.18s (± 0.19%)	+0.01s (+ 0.61%)	2.18s	2.19s	p=0.024 n=6
Bind Time	1.11s (± 0.68%)	1.11s (± 0.37%)	~	1.11s	1.12s	p=1.000 n=6
Check Time	7.21s (± 0.47%)	7.25s (± 0.26%)	~	7.23s	7.27s	p=0.139 n=6
Emit Time	3.98s (± 0.29%)	3.97s (± 0.32%)	~	3.95s	3.98s	p=0.210 n=6
Total Time	14.47s (± 0.29%)	14.51s (± 0.14%)	~	14.49s	14.54s	p=0.157 n=6
material-ui - node (v16.17.1, x64)
Memory used	479,537k (± 0.00%)	479,553k (± 0.00%)	~	479,524k	479,583k	p=0.378 n=6
Parse Time	3.15s (± 0.13%)	3.15s (± 0.48%)	~	3.14s	3.18s	p=0.490 n=6
Bind Time	0.91s (± 0.00%)	0.91s (± 0.45%)	~	0.90s	0.91s	p=0.405 n=6
Check Time	17.85s (± 0.24%)	17.85s (± 0.29%)	~	17.79s	17.93s	p=1.000 n=6
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	~	0.00s	0.00s	p=1.000 n=6
Total Time	21.91s (± 0.21%)	21.92s (± 0.27%)	~	21.85s	21.99s	p=0.871 n=6
xstate - node (v16.17.1, x64)
Memory used	542,853k (± 0.02%)	542,844k (± 0.01%)	~	542,796k	542,881k	p=0.689 n=6
Parse Time	3.69s (± 0.17%)	3.69s (± 0.32%)	~	3.67s	3.70s	p=1.000 n=6
Bind Time	1.40s (± 4.59%)	1.42s (± 4.16%)	~	1.34s	1.47s	p=0.678 n=6
Check Time	3.24s (± 2.45%)	3.22s (± 2.35%)	~	3.15s	3.32s	p=0.935 n=6
Emit Time	0.09s (± 6.44%)	0.09s (± 4.62%)	~	0.08s	0.09s	p=0.282 n=6
Total Time	8.41s (± 0.24%)	8.42s (± 0.37%)	~	8.37s	8.45s	p=0.627 n=6

System info unknown

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	pr	6
Baseline	baseline	6

tsserver

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
Compiler-UnionsTSServer - node (v16.17.1, x64)
Req 1 - updateOpen	2,487ms (± 0.13%)	2,490ms (± 0.23%)	~	2,482ms	2,498ms	p=0.378 n=6
Req 2 - geterr	5,950ms (± 0.48%)	5,959ms (± 0.42%)	~	5,929ms	5,986ms	p=0.470 n=6
Req 3 - references	342ms (± 0.15%)	342ms (± 0.66%)	~	338ms	344ms	p=0.113 n=6
Req 4 - navto	277ms (± 0.95%)	277ms (± 0.99%)	~	274ms	280ms	p=0.682 n=6
Req 5 - completionInfo count	1,356 (± 0.00%)	1,356 (± 0.00%)	~	1,356	1,356	p=1.000 n=6
Req 5 - completionInfo	81ms (± 5.69%)	85ms (± 5.74%)	~	80ms	93ms	p=0.332 n=6
CompilerTSServer - node (v16.17.1, x64)
Req 1 - updateOpen	2,624ms (± 0.46%)	2,632ms (± 1.21%)	~	2,605ms	2,685ms	p=0.809 n=6
Req 2 - geterr	4,772ms (± 0.26%)	4,772ms (± 0.35%)	~	4,747ms	4,796ms	p=1.000 n=6
Req 3 - references	351ms (± 0.35%)	350ms (± 0.33%)	~	349ms	352ms	p=0.507 n=6
Req 4 - navto	269ms (± 0.38%)	269ms (± 0.19%)	~	268ms	269ms	p=0.928 n=6
Req 5 - completionInfo count	1,518 (± 0.00%)	1,518 (± 0.00%)	~	1,518	1,518	p=1.000 n=6
Req 5 - completionInfo	78ms (± 3.39%)	79ms (± 0.95%)	~	78ms	80ms	p=0.604 n=6
xstateTSServer - node (v16.17.1, x64)
Req 1 - updateOpen	2,706ms (± 0.20%)	2,704ms (± 0.14%)	~	2,699ms	2,710ms	p=0.629 n=6
Req 2 - geterr	1,930ms (± 2.41%)	1,974ms (± 0.67%)	+44ms (+ 2.25%)	1,950ms	1,986ms	p=0.045 n=6
Req 3 - references	133ms (± 7.69%)	139ms (± 1.73%)	~	136ms	142ms	p=0.167 n=6
Req 4 - navto	358ms (± 1.11%)	360ms (± 0.71%)	~	358ms	365ms	p=0.290 n=6
Req 5 - completionInfo count	2,071 (± 0.00%)	2,071 (± 0.00%)	~	2,071	2,071	p=1.000 n=6
Req 5 - completionInfo	317ms (± 1.62%)	325ms (± 1.43%)	+9ms (+ 2.69%)	316ms	328ms	p=0.022 n=6

System info unknown

Hosts

• node (v16.17.1, x64)

Scenarios

• CompilerTSServer - node (v16.17.1, x64)
• Compiler-UnionsTSServer - node (v16.17.1, x64)
• xstateTSServer - node (v16.17.1, x64)

Benchmark	Name	Iterations
Current	pr	6
Baseline	baseline	6

Startup

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
tsc-startup - node (v16.17.1, x64)
Execution time	156.74ms (± 0.21%)	156.86ms (± 0.19%)	+0.11ms (+ 0.07%)	155.03ms	159.92ms	p=0.006 n=600
tsserver-startup - node (v16.17.1, x64)
Execution time	230.77ms (± 0.12%)	231.57ms (± 0.14%)	+0.80ms (+ 0.34%)	230.07ms	238.29ms	p=0.000 n=600
tsserverlibrary-startup - node (v16.17.1, x64)
Execution time	235.49ms (± 0.12%)	235.98ms (± 0.12%)	+0.50ms (+ 0.21%)	234.74ms	239.72ms	p=0.000 n=600
typescript-startup - node (v16.17.1, x64)
Execution time	235.67ms (± 0.11%)	235.59ms (± 0.12%)	-0.08ms (- 0.04%)	234.30ms	238.57ms	p=0.000 n=600

System info unknown

Hosts

• node (v16.17.1, x64)

Scenarios

• tsc-startup - node (v16.17.1, x64)
• tsserver-startup - node (v16.17.1, x64)
• tsserverlibrary-startup - node (v16.17.1, x64)
• typescript-startup - node (v16.17.1, x64)

Benchmark	Name	Iterations
Current	pr	6
Baseline	baseline	6

Developer Information:

Download Benchmarks

[typescript-bot]

@andrewbranch Here are the results of running the top-repos suite comparing main and refs/pull/55588/merge:

Everything looks good!

[andrewbranch]

Works for me. @DanielRosenwasser any objection to the API addition? I kind of like it.

[sandersn]

@Andarist this looks like it's ready to go except for checking on test results. Do you want to finish this up? Otherwise I'll probably close it for housekeeping purposes.

[jakebailey]

I think we just forgot about this. In microsoft/typescript-go#2067, I revamped the unreachable code detection in a way that effectively does what this PR did. I'm glad we were planning on merging this because I was having a hell of a time rationalizing the old behavior.