Regression performance compiling types in version 5.4.2

🔎 Search Terms

"regression", "5.4.2", "performance"

🕗 Version & Regression Information

• This changed between versions 5.3.3 and 5.4.2

⏯ Playground Link

No response

💻 Code

Extended diagnostics in version 5.4.2

Files:                          4294
Lines of Library:              40640
Lines of Definitions:         180807
Lines of TypeScript:          430513
Lines of JavaScript:               0
Lines of JSON:                     0
Lines of Other:                    0
Identifiers:                  591567
Symbols:                     1232510
Types:                       4677381
Instantiations:            395496734
Memory used:                2330550K
Assignability cache size:    3974893
Identity cache size:           14482
Subtype cache size:            37794
Strict subtype cache size:      9374
I/O Read time:                 0.70s
Parse time:                    0.96s
ResolveModule time:            0.58s
ResolveTypeReference time:     0.01s
ResolveLibrary time:           0.01s
Program time:                  2.51s
Bind time:                     0.62s
Check time:                  367.45s
printTime time:                0.00s
Emit time:                     0.00s
Total time:                  370.58s

Extended diagnostics in version 5.3.3

Files:                         4290
Lines of Library:             40241
Lines of Definitions:        180807
Lines of TypeScript:         430513
Lines of JavaScript:              0
Lines of JSON:                    0
Lines of Other:                   0
Identifiers:                 591320
Symbols:                    1234773
Types:                       699200
Instantiations:             2247099
Memory used:               1308962K
Assignability cache size:    223823
Identity cache size:          14479
Subtype cache size:           28353
Strict subtype cache size:     9128
I/O Read time:                0.73s
Parse time:                   1.11s
ResolveModule time:           0.44s
ResolveTypeReference time:    0.01s
ResolveLibrary time:          0.02s
Program time:                 2.60s
Bind time:                    0.76s
Check time:                  13.75s
printTime time:               0.00s
Emit time:                    0.00s
Total time:                  17.11s

🙁 Actual behavior

The type validation using tsc --noEmit increase more than 20 times using the version 5.4.2 comparing with the version 5.3.3.

In the CI is always hitting the heap memory limit:

🙂 Expected behavior

I expected the compilation to be equivalent in both versions, but it was more than 20 times slower.

Additional information about the issue

No response

Start by reproducing the reported tsc --noEmit comparison on the project that produced the diagnostics, using TypeScript 5.3.3 and 5.4.2. Compare extended diagnostics and isolate the source of the increase in check time, memory, and instantiations; done means a confirmed regression with a focused reproduction or regression test and a validated fix.