Narrow unions to the narrowest constituent on assignment

[Zzzen (Zzzen)]

Fixes #47731

[Ryan Cavanaugh (RyanCavanaugh)]

TypeScript Bot (@typescript-bot) user test this

[TypeScript Bot (typescript-bot)]

Heya Ryan Cavanaugh (@RyanCavanaugh), I've started to run the parallelized community code test suite on this PR at ead264a. You can monitor the build here.

[TypeScript Bot (typescript-bot)]

The user suite test run you requested has finished and failed. I've opened a PR with the baseline diff from master.

[Ryan Cavanaugh (RyanCavanaugh)]

TypeScript Bot (@typescript-bot) test this

[TypeScript Bot (typescript-bot)]

Heya Ryan Cavanaugh (@RyanCavanaugh), I've started to run the extended test suite on this PR at ead264a. You can monitor the build here.

[Ryan Cavanaugh (RyanCavanaugh)]

TypeScript Bot (@typescript-bot) perf test this

[TypeScript Bot (typescript-bot)]

Heya Ryan Cavanaugh (@RyanCavanaugh), I've started to run the perf test suite on this PR at ead264a. You can monitor the build here.

Update: The results are in!

[TypeScript Bot (typescript-bot)]

Ryan Cavanaugh (@RyanCavanaugh)
The results of the perf run you requested are in!

Here they are:

Comparison Report - main..47975

Metric	main	47975	Delta	Best	Worst
Angular - node (v10.16.3, x64)
Memory used	356,651k (± 0.02%)	356,781k (± 0.01%)	+130k (+ 0.04%)	356,693k	356,880k
Parse Time	2.03s (± 0.60%)	2.04s (± 0.59%)	+0.01s (+ 0.69%)	2.02s	2.07s
Bind Time	0.86s (± 0.80%)	0.86s (± 0.75%)	+0.01s (+ 0.70%)	0.85s	0.87s
Check Time	5.67s (± 0.28%)	5.70s (± 0.55%)	+0.02s (+ 0.39%)	5.63s	5.76s
Emit Time	5.90s (± 0.46%)	5.93s (± 0.71%)	+0.03s (+ 0.59%)	5.87s	6.06s
Total Time	14.45s (± 0.31%)	14.53s (± 0.46%)	+0.08s (+ 0.55%)	14.41s	14.70s
Compiler-Unions - node (v10.16.3, x64)
Memory used	205,560k (± 0.03%)	210,038k (± 0.46%)	+4,479k (+ 2.18%)	209,195k	212,685k
Parse Time	0.83s (± 0.54%)	0.83s (± 0.71%)	+0.00s (+ 0.24%)	0.82s	0.84s
Bind Time	0.53s (± 1.14%)	0.53s (± 1.13%)	+0.00s (+ 0.19%)	0.51s	0.54s
Check Time	7.82s (± 0.62%)	9.43s (± 0.79%)	+1.61s (+20.53%)	9.23s	9.55s
Emit Time	2.50s (± 1.14%)	2.50s (± 1.33%)	+0.01s (+ 0.24%)	2.41s	2.57s
Total Time	11.68s (± 0.50%)	13.30s (± 0.78%)	+1.62s (+13.83%)	13.02s	13.45s
Monaco - node (v10.16.3, x64)
Memory used	343,281k (± 0.03%)	343,255k (± 0.03%)	-26k (- 0.01%)	343,049k	343,524k
Parse Time	1.56s (± 0.61%)	1.56s (± 0.74%)	+0.00s (+ 0.19%)	1.53s	1.59s
Bind Time	0.76s (± 0.73%)	0.76s (± 0.62%)	+0.01s (+ 0.66%)	0.75s	0.77s
Check Time	5.59s (± 0.46%)	5.61s (± 0.52%)	+0.02s (+ 0.30%)	5.54s	5.66s
Emit Time	3.23s (± 0.93%)	3.24s (± 0.87%)	+0.00s (+ 0.06%)	3.18s	3.30s
Total Time	11.14s (± 0.34%)	11.16s (± 0.36%)	+0.02s (+ 0.22%)	11.04s	11.23s
TFS - node (v10.16.3, x64)
Memory used	305,060k (± 0.02%)	305,085k (± 0.02%)	+25k (+ 0.01%)	304,877k	305,184k
Parse Time	1.26s (± 0.41%)	1.28s (± 0.78%)	+0.02s (+ 1.67%)	1.26s	1.31s
Bind Time	0.71s (± 0.52%)	0.72s (± 1.06%)	+0.00s (+ 0.14%)	0.70s	0.73s
Check Time	5.15s (± 0.64%)	5.14s (± 0.48%)	-0.01s (- 0.16%)	5.07s	5.20s
Emit Time	3.38s (± 1.01%)	3.37s (± 0.91%)	-0.01s (- 0.27%)	3.31s	3.45s
Total Time	10.50s (± 0.44%)	10.50s (± 0.47%)	+0.00s (+ 0.01%)	10.37s	10.64s
material-ui - node (v10.16.3, x64)
Memory used	468,782k (± 0.01%)	468,771k (± 0.01%)	-11k (- 0.00%)	468,672k	468,879k
Parse Time	1.81s (± 0.45%)	1.81s (± 0.69%)	+0.00s (+ 0.17%)	1.79s	1.85s
Bind Time	0.66s (± 1.01%)	0.67s (± 1.12%)	+0.01s (+ 1.66%)	0.66s	0.69s
Check Time	14.08s (± 0.35%)	14.16s (± 0.58%)	+0.08s (+ 0.54%)	13.99s	14.32s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	16.55s (± 0.31%)	16.64s (± 0.52%)	+0.09s (+ 0.55%)	16.47s	16.82s
xstate - node (v10.16.3, x64)
Memory used	574,411k (± 1.38%)	574,337k (± 1.38%)	-73k (- 0.01%)	570,586k	606,391k
Parse Time	2.58s (± 0.45%)	2.59s (± 0.49%)	+0.01s (+ 0.23%)	2.56s	2.62s
Bind Time	1.02s (± 0.36%)	1.03s (± 0.39%)	+0.00s (+ 0.39%)	1.02s	1.04s
Check Time	1.51s (± 0.83%)	1.50s (± 0.58%)	-0.01s (- 0.33%)	1.49s	1.52s
Emit Time	0.07s (± 0.00%)	0.07s (± 0.00%)	0.00s ( 0.00%)	0.07s	0.07s
Total Time	5.18s (± 0.42%)	5.18s (± 0.35%)	+0.01s (+ 0.12%)	5.14s	5.22s
Angular - node (v12.1.0, x64)
Memory used	334,578k (± 0.02%)	334,428k (± 0.09%)	-150k (- 0.04%)	333,216k	334,699k
Parse Time	2.03s (± 0.85%)	2.03s (± 0.74%)	+0.00s (+ 0.15%)	1.99s	2.06s
Bind Time	0.84s (± 1.01%)	0.84s (± 0.77%)	-0.00s (- 0.12%)	0.83s	0.85s
Check Time	5.48s (± 0.51%)	5.51s (± 0.74%)	+0.03s (+ 0.46%)	5.43s	5.64s
Emit Time	6.12s (± 0.21%)	6.21s (± 0.88%)	+0.09s (+ 1.44%)	6.13s	6.34s
Total Time	14.48s (± 0.31%)	14.59s (± 0.68%)	+0.11s (+ 0.78%)	14.38s	14.84s
Compiler-Unions - node (v12.1.0, x64)
Memory used	192,969k (± 0.15%)	195,933k (± 0.03%)	+2,964k (+ 1.54%)	195,804k	196,089k
Parse Time	0.83s (± 0.78%)	0.84s (± 0.71%)	+0.00s (+ 0.48%)	0.82s	0.85s
Bind Time	0.54s (± 0.93%)	0.54s (± 0.83%)	+0.00s (+ 0.56%)	0.53s	0.55s
Check Time	7.41s (± 0.58%)	8.84s (± 0.64%)	+1.43s (+19.30%)	8.68s	8.97s
Emit Time	2.50s (± 1.02%)	2.49s (± 1.21%)	-0.02s (- 0.64%)	2.42s	2.58s
Total Time	11.28s (± 0.48%)	12.70s (± 0.59%)	+1.42s (+12.58%)	12.50s	12.82s
Monaco - node (v12.1.0, x64)
Memory used	326,057k (± 0.08%)	326,133k (± 0.06%)	+76k (+ 0.02%)	325,440k	326,405k
Parse Time	1.53s (± 0.58%)	1.54s (± 0.60%)	+0.01s (+ 0.59%)	1.52s	1.56s
Bind Time	0.74s (± 0.70%)	0.74s (± 1.02%)	+0.00s (+ 0.40%)	0.73s	0.76s
Check Time	5.49s (± 0.43%)	5.50s (± 0.37%)	+0.01s (+ 0.26%)	5.45s	5.55s
Emit Time	3.25s (± 1.53%)	3.24s (± 0.79%)	-0.02s (- 0.55%)	3.19s	3.32s
Total Time	11.01s (± 0.51%)	11.02s (± 0.41%)	+0.01s (+ 0.06%)	10.93s	11.16s
TFS - node (v12.1.0, x64)
Memory used	289,724k (± 0.02%)	289,783k (± 0.02%)	+59k (+ 0.02%)	289,693k	289,871k
Parse Time	1.28s (± 0.78%)	1.29s (± 0.58%)	+0.01s (+ 0.55%)	1.28s	1.31s
Bind Time	0.71s (± 1.26%)	0.70s (± 0.83%)	-0.00s (- 0.42%)	0.69s	0.71s
Check Time	5.07s (± 0.37%)	5.08s (± 0.55%)	+0.01s (+ 0.18%)	5.04s	5.16s
Emit Time	3.43s (± 0.39%)	3.46s (± 0.97%)	+0.03s (+ 0.87%)	3.38s	3.54s
Total Time	10.50s (± 0.37%)	10.54s (± 0.52%)	+0.04s (+ 0.37%)	10.44s	10.69s
material-ui - node (v12.1.0, x64)
Memory used	447,831k (± 0.07%)	447,913k (± 0.06%)	+82k (+ 0.02%)	446,871k	448,152k
Parse Time	1.80s (± 0.50%)	1.81s (± 0.55%)	+0.01s (+ 0.78%)	1.79s	1.84s
Bind Time	0.64s (± 0.78%)	0.64s (± 0.62%)	+0.01s (+ 0.94%)	0.63s	0.65s
Check Time	12.84s (± 0.82%)	12.79s (± 1.07%)	-0.05s (- 0.38%)	12.63s	13.27s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	15.27s (± 0.72%)	15.24s (± 0.90%)	-0.03s (- 0.21%)	15.09s	15.73s
xstate - node (v12.1.0, x64)
Memory used	536,795k (± 0.01%)	536,915k (± 0.01%)	+120k (+ 0.02%)	536,797k	537,109k
Parse Time	2.54s (± 0.51%)	2.54s (± 0.60%)	+0.01s (+ 0.24%)	2.52s	2.59s
Bind Time	1.05s (± 0.62%)	1.05s (± 0.49%)	-0.00s (- 0.10%)	1.04s	1.06s
Check Time	1.47s (± 0.66%)	1.46s (± 0.48%)	-0.01s (- 0.68%)	1.44s	1.47s
Emit Time	0.07s (± 0.00%)	0.07s (± 0.00%)	0.00s ( 0.00%)	0.07s	0.07s
Total Time	5.12s (± 0.41%)	5.12s (± 0.34%)	-0.01s (- 0.14%)	5.09s	5.17s
Angular - node (v14.15.1, x64)
Memory used	332,869k (± 0.01%)	332,860k (± 0.01%)	-10k (- 0.00%)	332,798k	332,883k
Parse Time	2.01s (± 0.44%)	2.03s (± 0.58%)	+0.02s (+ 0.79%)	2.00s	2.06s
Bind Time	0.90s (± 1.07%)	0.90s (± 0.77%)	0.00s ( 0.00%)	0.88s	0.91s
Check Time	5.51s (± 0.48%)	5.54s (± 0.54%)	+0.04s (+ 0.73%)	5.45s	5.60s
Emit Time	6.26s (± 0.71%)	6.25s (± 0.44%)	-0.01s (- 0.10%)	6.20s	6.31s
Total Time	14.67s (± 0.39%)	14.72s (± 0.32%)	+0.05s (+ 0.36%)	14.65s	14.82s
Compiler-Unions - node (v14.15.1, x64)
Memory used	192,420k (± 0.50%)	196,428k (± 0.64%)	+4,009k (+ 2.08%)	194,407k	198,506k
Parse Time	0.85s (± 0.87%)	0.85s (± 0.87%)	0.00s ( 0.00%)	0.84s	0.87s
Bind Time	0.57s (± 0.84%)	0.57s (± 0.64%)	-0.00s (- 0.18%)	0.56s	0.57s
Check Time	7.43s (± 0.71%)	8.90s (± 0.97%)	+1.47s (+19.73%)	8.68s	9.16s
Emit Time	2.50s (± 1.19%)	2.48s (± 0.86%)	-0.01s (- 0.60%)	2.43s	2.54s
Total Time	11.35s (± 0.53%)	12.80s (± 0.71%)	+1.45s (+12.78%)	12.52s	13.05s
Monaco - node (v14.15.1, x64)
Memory used	325,003k (± 0.00%)	325,027k (± 0.00%)	+25k (+ 0.01%)	325,001k	325,064k
Parse Time	1.57s (± 1.24%)	1.56s (± 0.64%)	-0.01s (- 0.51%)	1.55s	1.59s
Bind Time	0.77s (± 0.98%)	0.77s (± 0.84%)	-0.00s (- 0.26%)	0.76s	0.79s
Check Time	5.39s (± 0.40%)	5.40s (± 0.48%)	+0.01s (+ 0.19%)	5.33s	5.47s
Emit Time	3.27s (± 0.80%)	3.28s (± 0.55%)	+0.01s (+ 0.18%)	3.24s	3.34s
Total Time	11.00s (± 0.35%)	11.01s (± 0.31%)	+0.01s (+ 0.08%)	10.96s	11.13s
TFS - node (v14.15.1, x64)
Memory used	288,585k (± 0.01%)	288,587k (± 0.01%)	+2k (+ 0.00%)	288,542k	288,619k
Parse Time	1.30s (± 0.95%)	1.29s (± 0.74%)	-0.01s (- 0.54%)	1.28s	1.32s
Bind Time	0.74s (± 1.30%)	0.75s (± 0.50%)	+0.01s (+ 1.36%)	0.74s	0.75s
Check Time	5.06s (± 0.57%)	5.07s (± 0.76%)	+0.00s (+ 0.10%)	5.00s	5.17s
Emit Time	3.53s (± 1.68%)	3.55s (± 1.38%)	+0.02s (+ 0.59%)	3.38s	3.63s
Total Time	10.64s (± 0.82%)	10.66s (± 0.74%)	+0.03s (+ 0.25%)	10.41s	10.82s
material-ui - node (v14.15.1, x64)
Memory used	446,228k (± 0.00%)	446,107k (± 0.05%)	-120k (- 0.03%)	445,202k	446,323k
Parse Time	1.86s (± 0.66%)	1.86s (± 0.89%)	+0.00s (+ 0.05%)	1.83s	1.90s
Bind Time	0.70s (± 0.49%)	0.69s (± 0.49%)	-0.00s (- 0.57%)	0.69s	0.70s
Check Time	12.85s (± 0.70%)	12.99s (± 0.61%)	+0.14s (+ 1.10%)	12.84s	13.21s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	15.41s (± 0.64%)	15.55s (± 0.57%)	+0.14s (+ 0.91%)	15.39s	15.79s
xstate - node (v14.15.1, x64)
Memory used	534,541k (± 0.01%)	534,597k (± 0.01%)	+56k (+ 0.01%)	534,532k	534,644k
Parse Time	2.58s (± 0.47%)	2.58s (± 0.42%)	+0.01s (+ 0.23%)	2.55s	2.60s
Bind Time	1.16s (± 1.23%)	1.17s (± 0.71%)	+0.00s (+ 0.34%)	1.15s	1.19s
Check Time	1.50s (± 0.48%)	1.51s (± 0.76%)	+0.01s (+ 0.53%)	1.49s	1.54s
Emit Time	0.07s (± 4.13%)	0.07s (± 3.14%)	-0.00s (- 1.39%)	0.07s	0.08s
Total Time	5.32s (± 0.36%)	5.34s (± 0.29%)	+0.02s (+ 0.34%)	5.31s	5.38s

System

Machine Name	ts-ci-ubuntu
Platform	linux 4.4.0-210-generic
Architecture	x64
Available Memory	16 GB
Available Memory	5 GB
CPUs	4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

Hosts

• node (v10.16.3, x64)
• node (v12.1.0, x64)
• node (v14.15.1, x64)

Scenarios

• Angular - node (v10.16.3, x64)
• Angular - node (v12.1.0, x64)
• Angular - node (v14.15.1, x64)
• Compiler-Unions - node (v10.16.3, x64)
• Compiler-Unions - node (v12.1.0, x64)
• Compiler-Unions - node (v14.15.1, x64)
• Monaco - node (v10.16.3, x64)
• Monaco - node (v12.1.0, x64)
• Monaco - node (v14.15.1, x64)
• TFS - node (v10.16.3, x64)
• TFS - node (v12.1.0, x64)
• TFS - node (v14.15.1, x64)
• material-ui - node (v10.16.3, x64)
• material-ui - node (v12.1.0, x64)
• material-ui - node (v14.15.1, x64)
• xstate - node (v10.16.3, x64)
• xstate - node (v12.1.0, x64)
• xstate - node (v14.15.1, x64)

Benchmark	Name	Iterations
Current	47975	10
Baseline	main	10

Developer Information:

Download Benchmark

[Ryan Cavanaugh (RyanCavanaugh)]

+1.45s (+12.78%) 😭

I don't think we can take this as-is (Compiler Unions project is fairly representative of union-heavy codebases) given the original bug isn't super compelling.

[Zzzen (Zzzen)]

ok, nothing to see here

[Matt Hargett (matthargett)]

Can we re-open this PR and rebase to recheck the performance now? I'm actually running into this problem, the ergonomics are not great.

[Zzzen (Zzzen)]

The performance is unlikely to change. But it could be improved by caching. Do you know how to try the performance test suite at home? Ryan Cavanaugh (@RyanCavanaugh)