Narrow generic conditional and indexed access return types when checking return statements, no conditional expression support

[gabritto]

A version of #56941 without any of the extra stuff for checking conditional expressions.

[gabritto]

@typescript-bot perf test this

[typescript-bot]

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

Command	Status	Results
perf test this	✅ Started	👀 Results

[typescript-bot]

@gabritto 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	31	31	~	~	~	p=1.000 n=6
Symbols	62,340	62,337	-3 (- 0.00%)	~	~	p=0.001 n=6
Types	50,379	50,378	-1 (- 0.00%)	~	~	p=0.001 n=6
Memory used	195,069k (± 0.92%)	194,890k (± 1.00%)	~	192,989k	196,699k	p=0.378 n=6
Parse Time	1.32s (± 0.64%)	1.30s (± 0.63%)	-0.01s (- 0.89%)	1.29s	1.31s	p=0.045 n=6
Bind Time	0.72s	0.72s (± 0.57%)	~	0.71s	0.72s	p=0.405 n=6
Check Time	9.72s (± 0.73%)	9.78s (± 0.26%)	~	9.75s	9.82s	p=0.107 n=6
Emit Time	2.75s (± 1.00%)	2.73s (± 0.38%)	~	2.72s	2.75s	p=0.220 n=6
Total Time	14.50s (± 0.43%)	14.54s (± 0.16%)	~	14.51s	14.58s	p=0.419 n=6
angular-1 - node (v18.15.0, x64)
Errors	33	33	~	~	~	p=1.000 n=6
Symbols	947,886	947,576	-310 (- 0.03%)	~	~	p=0.001 n=6
Types	410,840	410,700	-140 (- 0.03%)	~	~	p=0.001 n=6
Memory used	1,224,815k (± 0.00%)	1,225,876k (± 0.00%)	+1,061k (+ 0.09%)	1,225,813k	1,225,971k	p=0.005 n=6
Parse Time	8.04s (± 0.73%)	8.12s (± 0.89%)	~	8.02s	8.23s	p=0.065 n=6
Bind Time	2.28s (± 0.66%)	2.27s (± 1.23%)	~	2.24s	2.31s	p=0.745 n=6
Check Time	37.92s (± 0.31%)	37.94s (± 0.29%)	~	37.78s	38.10s	p=0.809 n=6
Emit Time	18.33s (± 0.54%)	18.31s (± 0.49%)	~	18.19s	18.44s	p=1.000 n=6
Total Time	66.56s (± 0.29%)	66.64s (± 0.32%)	~	66.26s	66.86s	p=0.520 n=6
mui-docs - node (v18.15.0, x64)
Errors	0	0	~	~	~	p=1.000 n=6
Symbols	2,530,445	2,484,344	-46,101 (- 1.82%)	~	~	p=0.001 n=6
Types	916,594	914,759	-1,835 (- 0.20%)	~	~	p=0.001 n=6
Memory used	2,342,014k (± 0.00%)	2,332,708k (± 0.01%)	-9,306k (- 0.40%)	2,332,469k	2,332,962k	p=0.005 n=6
Parse Time	11.23s (± 0.52%)	11.19s (± 0.54%)	~	11.08s	11.24s	p=0.229 n=6
Bind Time	2.63s (± 0.57%)	2.62s (± 0.52%)	~	2.61s	2.64s	p=0.680 n=6
Check Time	90.94s (± 0.21%)	90.50s (± 0.30%)	-0.44s (- 0.48%)	89.98s	90.75s	p=0.020 n=6
Emit Time	0.36s (± 2.35%)	0.35s (± 2.14%)	~	0.34s	0.36s	p=0.652 n=6
Total Time	105.16s (± 0.21%)	104.66s (± 0.27%)	-0.50s (- 0.48%)	104.12s	104.92s	p=0.016 n=6
self-build-src - node (v18.15.0, x64)
Errors	0	0	~	~	~	p=1.000 n=6
Symbols	1,258,032	1,258,184	+152 (+ 0.01%)	~	~	p=0.001 n=6
Types	266,259	266,226	-33 (- 0.01%)	~	~	p=0.001 n=6
Memory used	3,146,643k (± 0.02%)	3,150,265k (± 0.03%)	+3,622k (+ 0.12%)	3,149,068k	3,151,551k	p=0.005 n=6
Parse Time	6.62s (± 0.46%)	6.56s (± 0.45%)	-0.06s (- 0.88%)	6.52s	6.61s	p=0.016 n=6
Bind Time	2.29s (± 4.46%)	2.35s (± 1.00%)	~	2.32s	2.38s	p=0.108 n=6
Check Time	43.11s (± 0.46%)	43.05s (± 0.20%)	~	42.94s	43.19s	p=0.748 n=6
Emit Time	3.47s (± 2.48%)	3.54s (± 3.51%)	~	3.31s	3.64s	p=0.199 n=6
Total Time	55.48s (± 0.58%)	55.52s (± 0.26%)	~	55.30s	55.68s	p=1.000 n=6
self-build-src-public-api - node (v18.15.0, x64)
Errors	0	0	~	~	~	p=1.000 n=6
Symbols	1,258,032	1,258,184	+152 (+ 0.01%)	~	~	p=0.001 n=6
Types	266,259	266,226	-33 (- 0.01%)	~	~	p=0.001 n=6
Memory used	2,765,526k (±12.86%)	2,742,220k (±13.57%)	~	2,501,137k	3,223,249k	p=0.378 n=6
Parse Time	8.33s (± 2.22%)	8.26s (± 2.63%)	~	8.06s	8.59s	p=0.378 n=6
Bind Time	2.72s (± 4.99%)	2.69s (± 3.77%)	~	2.57s	2.88s	p=1.000 n=6
Check Time	53.61s (± 0.85%)	53.53s (± 0.26%)	~	53.39s	53.68s	p=0.810 n=6
Emit Time	4.40s (± 3.18%)	4.34s (± 1.20%)	~	4.27s	4.39s	p=0.378 n=6
Total Time	69.05s (± 0.66%)	68.82s (± 0.24%)	~	68.65s	69.10s	p=0.423 n=6
self-compiler - node (v18.15.0, x64)
Errors	0	0	~	~	~	p=1.000 n=6
Symbols	261,789	262,141	+352 (+ 0.13%)	~	~	p=0.001 n=6
Types	106,511	106,574	+63 (+ 0.06%)	~	~	p=0.001 n=6
Memory used	438,806k (± 0.01%)	439,712k (± 0.02%)	+906k (+ 0.21%)	439,551k	439,792k	p=0.005 n=6
Parse Time	4.38s (± 1.05%)	4.38s (± 0.37%)	~	4.35s	4.40s	p=0.627 n=6
Bind Time	1.61s (± 1.87%)	1.62s (± 0.55%)	~	1.61s	1.63s	p=0.563 n=6
Check Time	23.41s (± 0.21%)	23.40s (± 0.41%)	~	23.30s	23.55s	p=0.688 n=6
Emit Time	1.91s (± 0.97%)	1.92s (± 1.45%)	~	1.89s	1.97s	p=0.935 n=6
Total Time	31.31s (± 0.31%)	31.32s (± 0.30%)	~	31.24s	31.47s	p=0.936 n=6
ts-pre-modules - node (v18.15.0, x64)
Errors	68	68	~	~	~	p=1.000 n=6
Symbols	225,919	225,912	-7 (- 0.00%)	~	~	p=0.001 n=6
Types	94,415	94,413	-2 (- 0.00%)	~	~	p=0.001 n=6
Memory used	371,082k (± 0.01%)	371,473k (± 0.01%)	+391k (+ 0.11%)	371,420k	371,532k	p=0.005 n=6
Parse Time	2.90s (± 0.38%)	2.90s (± 1.37%)	~	2.87s	2.96s	p=0.742 n=6
Bind Time	1.59s (± 1.34%)	1.57s (± 0.94%)	~	1.55s	1.59s	p=0.120 n=6
Check Time	16.40s (± 0.47%)	16.38s (± 0.15%)	~	16.35s	16.41s	p=0.374 n=6
Emit Time	0.00s	0.00s	~	~	~	p=1.000 n=6
Total Time	20.89s (± 0.38%)	20.85s (± 0.27%)	~	20.79s	20.93s	p=0.377 n=6
vscode - node (v18.15.0, x64)
Errors	3	3	~	~	~	p=1.000 n=6
Symbols	3,118,970	3,116,203	-2,767 (- 0.09%)	~	~	p=0.001 n=6
Types	1,075,058	1,073,952	-1,106 (- 0.10%)	~	~	p=0.001 n=6
Memory used	3,212,484k (± 0.01%)	3,216,787k (± 0.01%)	+4,304k (+ 0.13%)	3,215,965k	3,217,084k	p=0.005 n=6
Parse Time	11.56s (± 0.28%)	11.56s (± 0.12%)	~	11.55s	11.58s	p=0.459 n=6
Bind Time	3.70s (± 0.46%)	3.69s (± 0.22%)	~	3.68s	3.70s	p=0.402 n=6
Check Time	72.20s (± 0.45%)	72.31s (± 0.38%)	~	71.97s	72.72s	p=0.471 n=6
Emit Time	22.67s (± 0.70%)	22.89s (± 1.91%)	~	22.64s	23.78s	p=0.378 n=6
Total Time	110.12s (± 0.44%)	110.46s (± 0.48%)	~	109.97s	111.43s	p=0.378 n=6
webpack - node (v18.15.0, x64)
Errors	0	0	~	~	~	p=1.000 n=6
Symbols	286,241	286,097	-144 (- 0.05%)	~	~	p=0.001 n=6
Types	116,005	115,937	-68 (- 0.06%)	~	~	p=0.001 n=6
Memory used	436,644k (± 0.02%)	436,812k (± 0.02%)	+168k (+ 0.04%)	436,698k	436,900k	p=0.013 n=6
Parse Time	4.09s (± 0.95%)	4.08s (± 1.06%)	~	4.01s	4.14s	p=0.629 n=6
Bind Time	1.74s (± 1.42%)	1.75s (± 0.93%)	~	1.73s	1.77s	p=0.745 n=6
Check Time	18.44s (± 0.45%)	18.48s (± 0.43%)	~	18.41s	18.59s	p=0.468 n=6
Emit Time	0.00s	0.00s	~	~	~	p=1.000 n=6
Total Time	24.27s (± 0.34%)	24.30s (± 0.30%)	~	24.24s	24.43s	p=0.688 n=6
xstate-main - node (v18.15.0, x64)
Errors	3	3	~	~	~	p=1.000 n=6
Symbols	543,130	542,780	-350 (- 0.06%)	~	~	p=0.001 n=6
Types	181,889	181,659	-230 (- 0.13%)	~	~	p=0.001 n=6
Memory used	485,460k (± 0.02%)	486,156k (± 0.02%)	+696k (+ 0.14%)	486,053k	486,324k	p=0.005 n=6
Parse Time	3.35s (± 0.81%)	3.35s (± 0.53%)	~	3.32s	3.37s	p=0.513 n=6
Bind Time	1.18s (± 0.69%)	1.17s (± 1.05%)	~	1.15s	1.18s	p=0.120 n=6
Check Time	19.31s (± 2.13%)	19.13s (± 0.52%)	~	18.99s	19.25s	p=0.630 n=6
Emit Time	0.00s	0.00s (±244.70%)	~	0.00s	0.01s	p=0.405 n=6
Total Time	23.84s (± 1.75%)	23.64s (± 0.47%)	~	23.50s	23.78s	p=0.470 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

tsserver

Comparison Report - baseline..pr

Metric	baseline	pr	Delta	Best	Worst	p-value
Compiler-UnionsTSServer - node (v18.15.0, x64)
Req 1 - updateOpen	2,315ms (± 0.30%)	2,321ms (± 0.31%)	~	2,313ms	2,331ms	p=0.378 n=6
Req 2 - geterr	5,297ms (± 0.43%)	5,291ms (± 0.68%)	~	5,240ms	5,341ms	p=0.748 n=6
Req 3 - references	266ms (± 0.28%)	263ms (± 0.68%)	-3ms (- 1.19%)	261ms	266ms	p=0.014 n=6
Req 4 - navto	227ms (± 0.37%)	227ms (± 0.72%)	~	224ms	228ms	p=0.116 n=6
Req 5 - completionInfo count	1,357	1,357	~	~	~	p=1.000 n=6
Req 5 - completionInfo	81ms (± 5.15%)	82ms (± 6.14%)	~	76ms	91ms	p=0.685 n=6
CompilerTSServer - node (v18.15.0, x64)
Req 1 - updateOpen	2,442ms (± 1.10%)	2,446ms (± 0.97%)	~	2,410ms	2,466ms	p=0.748 n=6
Req 2 - geterr	3,973ms (± 0.50%)	3,968ms (± 0.16%)	~	3,960ms	3,977ms	p=0.810 n=6
Req 3 - references	282ms (± 1.08%)	278ms (± 1.07%)	-4ms (- 1.48%)	275ms	283ms	p=0.043 n=6
Req 4 - navto	226ms (± 0.28%)	235ms (± 2.78%)	+9ms (+ 3.91%)	226ms	240ms	p=0.019 n=6
Req 5 - completionInfo count	1,519	1,519	~	~	~	p=1.000 n=6
Req 5 - completionInfo	82ms (± 6.32%)	83ms (± 2.57%)	~	81ms	86ms	p=1.000 n=6
xstate-main-1-tsserver - node (v18.15.0, x64)
Req 1 - updateOpen	5,265ms (± 0.27%)	5,270ms (± 0.27%)	~	5,254ms	5,295ms	p=0.335 n=6
Req 2 - geterr	1,139ms (± 0.79%)	1,143ms (± 0.83%)	~	1,130ms	1,159ms	p=0.374 n=6
Req 3 - references	81ms (± 3.52%)	80ms	~	~	~	p=0.405 n=6
Req 4 - navto	447ms (± 0.30%)	444ms (± 1.34%)	~	436ms	448ms	p=0.557 n=6
Req 5 - completionInfo count	3,450	3,450	~	~	~	p=1.000 n=6
Req 5 - completionInfo	849ms (± 2.46%)	853ms (± 0.46%)	~	846ms	857ms	p=0.377 n=6

System info unknown

Hosts

• node (v18.15.0, x64)

Scenarios

• CompilerTSServer - node (v18.15.0, x64)
• Compiler-UnionsTSServer - node (v18.15.0, x64)
• xstate-main-1-tsserver - node (v18.15.0, 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 (v18.15.0, x64)
Execution time	183.96ms (± 0.21%)	184.40ms (± 0.19%)	+0.44ms (+ 0.24%)	182.10ms	188.22ms	p=0.000 n=600
tsserver-startup - node (v18.15.0, x64)
Execution time	234.37ms (± 0.15%)	234.57ms (± 0.16%)	+0.19ms (+ 0.08%)	233.12ms	241.80ms	p=0.000 n=600
tsserverlibrary-startup - node (v18.15.0, x64)
Execution time	229.63ms (± 0.14%)	229.86ms (± 0.15%)	+0.22ms (+ 0.10%)	228.36ms	235.93ms	p=0.000 n=600
typescript-startup - node (v18.15.0, x64)
Execution time	228.58ms (± 0.14%)	228.72ms (± 0.15%)	+0.14ms (+ 0.06%)	227.26ms	232.96ms	p=0.000 n=600

System info unknown

Hosts

• node (v18.15.0, x64)

Scenarios

• tsc-startup - node (v18.15.0, x64)
• tsserver-startup - node (v18.15.0, x64)
• tsserverlibrary-startup - node (v18.15.0, x64)
• typescript-startup - node (v18.15.0, x64)

Benchmark	Name	Iterations
Current	pr	6
Baseline	baseline	6

Developer Information:

Download Benchmarks

[Andarist]

@gabritto should this one perhaps be closed?