Too much compile time to resolve a complex function signiture definition.

[tetsuharuohzeki]

Example Environment

• [email protected]
• [email protected]

Abstraction

I found the case that the compile time of tsc increases to ~15x to resolve a complex function signature definition when I update rxjs to 5.0.0-beta.2 from 5.0.0-beta.1 (karen-irc/karen#574).

But after this commit, the compile time was recovered to the previous one.

	beta.1	beta.2	beta.2 + explicit type annotations
Files:	111	124	124
Lines:	28560	29011	29012
Nodes:	119182	125219	125258
Identifiers:	44304	46931	46945
Symbols:	2960494	5126214	3375603
Types:	66178	1069572	41087
Memory used:	165777K	1264781K	118627K
I/O read:	0.03s	0.04s	0.04s
I/O write:	0.32s	0.31s	0.22s
Parse time:	0.48s	0.73s	0.64s
Bind time:	0.28s	0.41s	0.31s
Check time:	1.83s	31.48s	1.67s
Emit time:	0.52s	1.53s	0.43s
Total time:	3.10s	34.15s	3.05s

[email protected] has some pretty complex type signitured functions:

• combineLatest()
• zip()

I know the type inference is not omnipotent, it need a complex computations, and this issue may be a corner-case of TypeScript compiler.
But I also think this would be a problem if libraries having a complex type signatures rises in the future.

Could you resolve this problem?

[RyanCavanaugh]

@vladima do you think this is related to the other perf regression we tracked down a couple weeks ago?

[tetsuharuohzeki]

As an additional information, I tried to upgrade to [email protected] from [email protected] for the private code of my day job.

This is the comparison (sorry, I forgot diagnostic options...):

• [email protected]
  • about 3.4s~4s
• [email protected]
  • the compilation has not completed after 2h!

This upgrading needs some migration to my code thus this is not simply comparison. But this indicates that the type definitions of rxjs v5 is more complex than v4.

[vladima]

Fix is checked in and should be available on today's nightly build: typescript@next on npm. Can you give it a try and check if it resolves your issue?

[tetsuharuohzeki]

okay, I'll try [email protected]

[vladima]

Seems that today's next does not include the fix, can you either try next tomorrow or use tsc.js built from master (I've pasted it here)

[tetsuharuohzeki]

@vladima

This is the result with [email protected] (on MacBook Pro (Retina, 15-inch, Mid 2014, 2.8 GHz Intel Core i7, 16 GB 1600 MHz DDR3))
I feel there would be no problem. Thank you!

	without type paramter	with type parameter explicitly
Files:	124	124
Lines:	29011	29012
Nodes:	125219	125258
Identifiers:	46931	46945
Symbols:	3401852	3376452
Types:	56016	41557
Memory used:	140577K	127098K
I/O read:	0.03s	0.04s
I/O write:	0.02s	0.02s
Parse time:	0.35s	0.36s
Bind time:	0.24s	0.23s
Check time:	1.24s	1.01s
Emit time:	0.15s	0.15s
Total time:	1.99s	1.75s

[vladima]

#7372 ports this fix to the next point release