Fix33448 #35513

ahejlsberg · 2019-12-05T01:08:28Z

Fixes #33448. Also fixes the issue in #33498 (comment).

This PR supercedes #33498. (Thanks @jack-williams!)

ahejlsberg · 2019-12-05T01:10:17Z

@typescript-bot test this
@typescript-bot user test this
@typescript-bot run dt
@typescript-bot perf test this

typescript-bot · 2019-12-05T01:10:22Z

Heya @ahejlsberg, I've started to run the parallelized Definitely Typed test suite on this PR at 6bc8b12. You can monitor the build here. It should now contribute to this PR's status checks.

typescript-bot · 2019-12-05T01:10:22Z

Heya @ahejlsberg, I've started to run the extended test suite on this PR at 6bc8b12. You can monitor the build here. It should now contribute to this PR's status checks.

typescript-bot · 2019-12-05T01:10:22Z

Heya @ahejlsberg, I've started to run the parallelized community code test suite on this PR at 6bc8b12. You can monitor the build here. It should now contribute to this PR's status checks.

typescript-bot · 2019-12-05T01:10:23Z

Heya @ahejlsberg, I've started to run the perf test suite on this PR at 6bc8b12. You can monitor the build here. It should now contribute to this PR's status checks.

Update: The results are in!

typescript-bot · 2019-12-05T01:34:13Z

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

Here they are:

Comparison Report - master..35513

Metric	master	35513	Delta	Best	Worst
Angular - node (v10.16.3, x64)
Memory used	354,807k (± 0.02%)	356,542k (± 0.02%)	+1,736k (+ 0.49%)	356,315k	356,620k
Parse Time	1.61s (± 0.60%)	1.63s (± 0.35%)	+0.02s (+ 1.31%)	1.62s	1.64s
Bind Time	0.86s (± 0.95%)	0.86s (± 0.77%)	+0.00s (+ 0.35%)	0.85s	0.87s
Check Time	4.53s (± 0.27%)	4.53s (± 0.61%)	+0.01s (+ 0.13%)	4.49s	4.60s
Emit Time	5.25s (± 0.47%)	5.22s (± 0.71%)	-0.02s (- 0.38%)	5.16s	5.31s
Total Time	12.24s (± 0.28%)	12.25s (± 0.43%)	+0.01s (+ 0.09%)	12.17s	12.38s
Monaco - node (v10.16.3, x64)
Memory used	366,213k (± 0.01%)	366,145k (± 0.01%)	-68k (- 0.02%)	366,038k	366,273k
Parse Time	1.25s (± 0.61%)	1.26s (± 0.85%)	+0.01s (+ 0.48%)	1.25s	1.29s
Bind Time	0.76s (± 0.49%)	0.76s (± 0.48%)	+0.00s (+ 0.13%)	0.75s	0.76s
Check Time	4.65s (± 0.59%)	4.66s (± 0.64%)	+0.01s (+ 0.28%)	4.58s	4.72s
Emit Time	2.93s (± 0.71%)	2.94s (± 0.50%)	+0.01s (+ 0.20%)	2.91s	2.98s
Total Time	9.58s (± 0.40%)	9.61s (± 0.48%)	+0.03s (+ 0.28%)	9.51s	9.73s
TFS - node (v10.16.3, x64)
Memory used	321,970k (± 0.03%)	321,977k (± 0.01%)	+7k (+ 0.00%)	321,915k	322,039k
Parse Time	0.95s (± 0.71%)	0.95s (± 0.86%)	-0.00s (- 0.10%)	0.94s	0.97s
Bind Time	0.73s (± 1.12%)	0.72s (± 1.38%)	-0.01s (- 0.96%)	0.70s	0.74s
Check Time	4.11s (± 0.35%)	4.14s (± 0.35%)	+0.03s (+ 0.66%)	4.10s	4.17s
Emit Time	3.04s (± 0.78%)	3.06s (± 0.65%)	+0.01s (+ 0.39%)	3.00s	3.10s
Total Time	8.83s (± 0.34%)	8.87s (± 0.33%)	+0.03s (+ 0.38%)	8.82s	8.95s
Angular - node (v12.1.0, x64)
Memory used	330,399k (± 0.04%)	332,012k (± 0.01%)	+1,612k (+ 0.49%)	331,945k	332,113k
Parse Time	1.57s (± 0.63%)	1.59s (± 0.56%)	+0.02s (+ 1.08%)	1.57s	1.61s
Bind Time	0.84s (± 0.68%)	0.85s (± 0.52%)	+0.01s (+ 1.43%)	0.84s	0.86s
Check Time	4.42s (± 0.44%)	4.47s (± 0.42%)	+0.05s (+ 1.15%)	4.43s	4.51s
Emit Time	5.47s (± 1.35%)	5.52s (± 0.68%)	+0.05s (+ 0.91%)	5.45s	5.62s
Total Time	12.30s (± 0.69%)	12.43s (± 0.32%)	+0.13s (+ 1.06%)	12.34s	12.53s
Monaco - node (v12.1.0, x64)
Memory used	345,927k (± 0.01%)	345,898k (± 0.01%)	-29k (- 0.01%)	345,827k	346,030k
Parse Time	1.23s (± 0.42%)	1.22s (± 0.61%)	-0.01s (- 0.73%)	1.20s	1.23s
Bind Time	0.72s (± 1.15%)	0.72s (± 0.65%)	-0.00s (- 0.69%)	0.71s	0.73s
Check Time	4.49s (± 0.27%)	4.49s (± 0.56%)	-0.01s (- 0.18%)	4.43s	4.54s
Emit Time	2.98s (± 1.31%)	2.98s (± 1.07%)	+0.00s (+ 0.07%)	2.93s	3.09s
Total Time	9.43s (± 0.42%)	9.41s (± 0.50%)	-0.02s (- 0.18%)	9.34s	9.53s
TFS - node (v12.1.0, x64)
Memory used	304,312k (± 0.02%)	304,352k (± 0.02%)	+40k (+ 0.01%)	304,231k	304,476k
Parse Time	0.95s (± 0.71%)	0.95s (± 1.00%)	+0.00s (+ 0.00%)	0.92s	0.96s
Bind Time	0.68s (± 0.69%)	0.68s (± 0.33%)	-0.00s (- 0.15%)	0.67s	0.68s
Check Time	4.05s (± 0.63%)	4.05s (± 0.44%)	+0.01s (+ 0.17%)	4.01s	4.09s
Emit Time	3.05s (± 1.01%)	3.07s (± 0.46%)	+0.02s (+ 0.69%)	3.04s	3.10s
Total Time	8.72s (± 0.50%)	8.75s (± 0.23%)	+0.03s (+ 0.33%)	8.70s	8.80s
Angular - node (v8.9.0, x64)
Memory used	349,620k (± 0.01%)	351,274k (± 0.01%)	+1,654k (+ 0.47%)	351,166k	351,312k
Parse Time	2.10s (± 0.40%)	2.11s (± 0.36%)	+0.01s (+ 0.62%)	2.10s	2.13s
Bind Time	0.91s (± 0.71%)	0.92s (± 0.79%)	+0.01s (+ 1.54%)	0.91s	0.94s
Check Time	5.29s (± 0.61%)	5.28s (± 0.54%)	-0.00s (- 0.08%)	5.23s	5.35s
Emit Time	6.23s (± 1.08%)	6.26s (± 0.71%)	+0.03s (+ 0.55%)	6.15s	6.37s
Total Time	14.52s (± 0.69%)	14.58s (± 0.36%)	+0.06s (+ 0.43%)	14.48s	14.72s
Monaco - node (v8.9.0, x64)
Memory used	364,019k (± 0.01%)	364,016k (± 0.01%)	-3k (- 0.00%)	363,893k	364,129k
Parse Time	1.56s (± 0.48%)	1.56s (± 0.31%)	0.00s ( 0.00%)	1.55s	1.57s
Bind Time	0.93s (± 0.78%)	0.93s (± 0.70%)	0.00s ( 0.00%)	0.91s	0.94s
Check Time	5.57s (± 0.59%)	5.56s (± 0.44%)	-0.01s (- 0.13%)	5.50s	5.60s
Emit Time	3.03s (± 0.62%)	3.04s (± 0.84%)	+0.01s (+ 0.20%)	3.00s	3.11s
Total Time	11.09s (± 0.41%)	11.09s (± 0.37%)	-0.00s (- 0.04%)	11.04s	11.20s
TFS - node (v8.9.0, x64)
Memory used	320,953k (± 0.01%)	320,948k (± 0.02%)	-5k (- 0.00%)	320,823k	321,050k
Parse Time	1.26s (± 0.51%)	1.26s (± 0.29%)	+0.00s (+ 0.16%)	1.26s	1.27s
Bind Time	0.74s (± 0.60%)	0.74s (± 0.75%)	-0.00s (- 0.00%)	0.73s	0.75s
Check Time	4.75s (± 0.40%)	4.73s (± 0.54%)	-0.02s (- 0.34%)	4.69s	4.81s
Emit Time	3.19s (± 0.95%)	3.19s (± 0.45%)	+0.00s (+ 0.03%)	3.17s	3.23s
Total Time	9.94s (± 0.48%)	9.93s (± 0.39%)	-0.02s (- 0.15%)	9.86s	10.02s
Angular - node (v8.9.0, x86)
Memory used	198,592k (± 0.02%)	199,462k (± 0.02%)	+870k (+ 0.44%)	199,388k	199,511k
Parse Time	2.03s (± 0.90%)	2.04s (± 0.39%)	+0.01s (+ 0.64%)	2.02s	2.06s
Bind Time	1.04s (± 1.19%)	1.01s (± 0.59%)	-0.03s (- 2.68%)	1.00s	1.03s
Check Time	4.81s (± 0.38%)	4.80s (± 0.52%)	-0.00s (- 0.04%)	4.77s	4.88s
Emit Time	6.01s (± 0.79%)	6.00s (± 0.46%)	-0.02s (- 0.30%)	5.94s	6.05s
Total Time	13.89s (± 0.46%)	13.86s (± 0.19%)	-0.03s (- 0.24%)	13.81s	13.93s
Monaco - node (v8.9.0, x86)
Memory used	203,931k (± 0.02%)	203,943k (± 0.03%)	+13k (+ 0.01%)	203,827k	204,076k
Parse Time	1.61s (± 0.90%)	1.62s (± 1.12%)	+0.01s (+ 0.37%)	1.59s	1.66s
Bind Time	0.74s (± 0.87%)	0.74s (± 0.80%)	+0.00s (+ 0.27%)	0.73s	0.76s
Check Time	5.40s (± 0.84%)	5.39s (± 1.19%)	-0.02s (- 0.31%)	5.15s	5.48s
Emit Time	2.88s (± 2.58%)	2.89s (± 2.67%)	+0.00s (+ 0.14%)	2.81s	3.18s
Total Time	10.65s (± 0.46%)	10.64s (± 0.49%)	-0.01s (- 0.06%)	10.53s	10.74s
TFS - node (v8.9.0, x86)
Memory used	180,831k (± 0.03%)	180,869k (± 0.02%)	+38k (+ 0.02%)	180,771k	180,947k
Parse Time	1.31s (± 0.85%)	1.30s (± 0.81%)	-0.00s (- 0.23%)	1.28s	1.33s
Bind Time	0.69s (± 0.99%)	0.70s (± 0.68%)	+0.00s (+ 0.29%)	0.69s	0.71s
Check Time	4.50s (± 0.74%)	4.47s (± 0.65%)	-0.03s (- 0.60%)	4.40s	4.55s
Emit Time	2.96s (± 0.71%)	2.97s (± 1.53%)	+0.01s (+ 0.27%)	2.85s	3.09s
Total Time	9.46s (± 0.63%)	9.44s (± 0.78%)	-0.02s (- 0.23%)	9.33s	9.63s

System

Machine Name	ts-ci-ubuntu
Platform	linux 4.4.0-166-generic
Architecture	x64
Available Memory	16 GB
Available Memory	6 GB
CPUs	4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

Hosts

node (v10.16.3, x64)
node (v12.1.0, x64)
node (v8.9.0, x64)
node (v8.9.0, x86)

Scenarios

Angular - node (v10.16.3, x64)
Angular - node (v12.1.0, x64)
Angular - node (v8.9.0, x64)
Angular - node (v8.9.0, x86)
Monaco - node (v10.16.3, x64)
Monaco - node (v12.1.0, x64)
Monaco - node (v8.9.0, x64)
Monaco - node (v8.9.0, x86)
TFS - node (v10.16.3, x64)
TFS - node (v12.1.0, x64)
TFS - node (v8.9.0, x64)
TFS - node (v8.9.0, x86)

Benchmark	Name	Iterations
Current	35513	10
Baseline	master	10

typescript-bot · 2019-12-05T01:41:05Z

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

ahejlsberg · 2019-12-05T15:08:33Z

RWC and Community test errors look to be preexisting conditions.

weswigham · 2019-12-05T16:32:34Z

RWC is clean on master. Maybe try syncing the branch and running again? Otherwise the change is real.

ahejlsberg · 2019-12-07T19:20:45Z

Looked at it more closely. The RWC difference is just simple error message change because we now pick a different (and arguably better) union constituent to elaborate.

weswigham · 2019-12-09T21:32:35Z

src/compiler/checker.ts

                        (<TransientSymbol>prop).isDiscriminantProperty =
                            ((<TransientSymbol>prop).checkFlags & CheckFlags.Discriminant) === CheckFlags.Discriminant &&
-                            isDiscriminantType(getTypeOfSymbol(prop));
+                            !maybeTypeOfKind(getTypeOfSymbol(prop), TypeFlags.Instantiable);


What's the justification for not maybe instantiables here? Previously it was "not generic indexes", so this is quite a bit broader an exclusion, if I'm not mistaken.

If you look at isGenericIndexType you'll see that it's more than just generic index types. The code change just clarifies what's actually going on, there's no change in behavior.

Huh, alright, so it's equivalent. Neat.

weswigham

Do we also need to apply/extended similar logic to conditionals in some way? Like if I have a
(T extends U ? { type: "a" } : { type: "b" }) & { type: "b" }, shouldn't it be similarly simplified (at least outside of when infer variables are present)?

ahejlsberg added 3 commits December 4, 2019 16:50

Filter out discriminants of type 'never'.

0929a2f

Add tests

220034d

Accept new baselines

6bc8b12

typescript-bot mentioned this pull request Dec 5, 2019

🤖 User test baselines have changed for fix33448 #35514

Closed

Remove unnecessary '!' assertion

c14b160

ahejlsberg requested review from RyanCavanaugh and weswigham December 5, 2019 15:07

Merge branch 'master' into fix33448

ec7e2c4

weswigham reviewed Dec 9, 2019

View reviewed changes

weswigham approved these changes Dec 9, 2019

View reviewed changes

ahejlsberg merged commit 71a9176 into master Dec 12, 2019

This was referenced Jan 21, 2020

Discriminated union intersected with discriminant does not join to the original type when discriminated #36333

Closed

Discriminated union not correctly narrowed by intersection #36323

Closed

jakebailey deleted the fix33448 branch November 7, 2022 17:34

microsoft locked as resolved and limited conversation to collaborators Oct 21, 2025

typescript-bot assigned ahejlsberg Oct 21, 2025

Fix33448 #35513

Fix33448 #35513

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