`Exception: java.lang.OutOfMemoryError` (diverging implicits)

Compiler version

3.1.1-RC1

Minimized code

https://github.com/armanbilge/schrodinger/commit/ed9a8bad6229fb8617615cf0397814b7a02fee52

Clone project in clean workspace and run sbt compile.

Apologies that this isn’t further minimized, not entirely sure how to approach this one. I’d appreciate any pointers.

FWIW it’s not a big project, and the module that seems to have the problem is 4 files with < 1k LOC total.

Output

[warn] In the last 8 seconds, 6.706 (86.2%) were spent in GC. [Heap: 0.10GB free of 4.00GB, max 4.00GB] Consider increasing the JVM heap using `-Xmx` or try a different collector, e.g. `-XX:+UseG1GC`, for better performance.

  | => monteCarlo / Compile / compileIncremental 312s

...

[warn] In the last 6 seconds, 5.215 (99.8%) were spent in GC. [Heap: 0.00GB free of 4.00GB, max 4.00GB] Consider increasing the JVM heap using `-Xmx` or try a different collector, e.g. `-XX:+UseG1GC`, for better performance.

Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "classloader-cache-cleanup-0

Note this occurs frequently, but not always. Sometimes it compiles just fine.

Expectation

My code compiles the first time and everything is hunky-dory 😃

[odersky]

I found a way to make the original test cases work without the search limit, by improving the way we recognize underspecified queries. The search limit is still there since there are other test cases where we need it.

[odersky]

@armanbilge Scala 2.13 treats diverging implicits differently from Scala 3 (and in a wrong way). I fear there’s not much we can do here. It’s a crazy combinatorial explosion of possibilities. The best thing to do would be to drop all these implicits and provide a general Order for 😗 instead. But that can only work in Scala 3 of course.

I won’t have the time to work on this, unfortunately. If nobody else takes this over until 30.11.2010, we will have to close the issue.