LambdaLift: reload non-sym denotations when needed #11303
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
smarter
force-pushed
the
lambdalift-transformSelect
branch
from
1a1257c to
63a2f00
Compare
|
Actually, do we need non-sym denotations after erasure? According to the comment on top of Compiler, they shouldn't exist: https://github.com/lampepfl/dotty/blob/44931da237f47a7fda2eb0b3b7f417757679e686/compiler/src/dotty/tools/dotc/Compiler.scala#L26-L33 Should we special case |
smarter
force-pushed
the
lambdalift-transformSelect
branch
from
63a2f00 to
1781238
Compare
smarter
force-pushed
the
lambdalift-transformSelect
branch
from
1781238 to
694e713
Compare
smarter
added a commit
to smarter/dotty
that referenced
this pull request
Feb 4, 2021
This is an alternative fix for scala#11303, the downside is that when time-travelling from post-erasure to pre-erasure, we need to recompute the SingleDenotation. This commit passes all tests except tests/pos/t2399.scala which fails compilation from tasty. This could probably be fixed by changing the logic in computeDenot to only run `memberDenot` for opaque types, for other infos we can just use `asSeenFrom` instead.
This idea is implemented in smarter@3ab00a8 but leads to other complications as explained in the commit message. |
odersky
approved these changes
Feb 4, 2021
smarter
added a commit
to smarter/dotty
that referenced
this pull request
Feb 5, 2021
The comment above `derived` used to say "Currently this fails bootstrap", this was fixed by scala#11303, and this commit takes care of updating the few places where we were assuming that something had to be a SymDenotation when it didn't. Nevertheless, we still keep essentially the same behavior of reusing denotations that existed before this commit for performance reason, but this is now toggleable using `Config.reuseSymDenotations`. There's one difference with what we did before: if we need to create a new denotation anyway because the info changed, then we always update the prefix at the same time, this doesn't cost us anything and means that we can rely on `prefix` being correctly set on non-sym denotations.
smarter
added a commit
to dotty-staging/dotty
that referenced
this pull request
Feb 6, 2021
The comment above `derived` used to say "Currently this fails bootstrap", this was fixed by scala#11303, and this commit takes care of updating the few places where we were assuming that something had to be a SymDenotation when it didn't. Nevertheless, we still keep essentially the same behavior of reusing denotations that existed before this commit for performance reason, but this is now toggleable using `Config.reuseSymDenotations`. There's one difference with what we did before: if we need to create a new denotation anyway because the info changed, then we always update the prefix at the same time, this doesn't cost us anything and means that we can rely on `prefix` being correctly set on non-sym denotations.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When we manually insert a SymDenotation with
installAfter, we need to reload any non-sym SingleDenotation for the same symbol, since they won't automatically become stale. It would be nicer if this was done automatically (in NonSymSingleDenotation#current perhaps?), but that seems complicated.