internal: stop expanding UseTrees during ItemTree lowering #8997
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Note that this somewhat regresses memory usage: |
matklad
reviewed
May 27, 2021
crates/hir_def/src/item_tree.rs
Outdated
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| #[derive(Debug, Clone, Eq, PartialEq)] | ||
| pub enum UseTreeKind { | ||
| /// ```ignore |
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No need for ignore, we disable doc tests for all internal crates to speed up compilation.
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LGTM but also, mad scientist idea. what if, to maintain fidelity with original source code and to save memory, we redefine use trees as compressions of original file? Basically, parse the file into SyntaxNode, remove all irrelevant syntax details (whitespace, comments, bodies), serialize back into text? That’s completely unrelated to the PR, but I wonder if that can give us some idea about memory usage? |
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Thinking about this more, I feel that we should switch to flat stubs at one point: #9023 |
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bors r+ |
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Closes #8908
Messy diff, but
ItemTreelowering got simpler, since we now have a strict 1-to-1 mapping betweenast::ItemandModItem.The most messy part is mapping a single
UseTreeback to itsast::UseTreecounterpart for diagnostics, but I think the ad-hoc source map built during lowering does the job.