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path: root/crates/libsyntax2/src/grammar/expressions
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* rename all thingsAleksey Kladov2018-09-162-850/+0
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* Implement reparsing for remaining blocksdarksv2018-09-102-2/+3
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* Fix yet another parser infinite loopAleksey Kladov2018-09-081-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit is an example of fixing a common parser error: infinite loop due to error recovery. This error typically happens when we parse a list of items and fail to parse a specific item at the current position. One choices is to skip a token and try to parse a list item at the next position. This is a good, but not universal, default. When parsing a list of arguments in a function call, you, for example, don't want to skip over `fn`, because it's most likely that it is a function declaration, and not a mistyped arg: ``` fn foo() { quux(1, 2 fn bar() { } ``` Another choice is to bail out of the loop immediately, but it isn't perfect either: sometimes skipping over garbage helps: ``` quux(1, foo:, 92) // should skip over `:`, b/c that's part of `foo::bar` ``` In general, parser tries to balance these two cases, though we don't have a definitive strategy yet. However, if the parser accidentally neither skips over a token, nor breaks out of the loop, then it becomes stuck in the loop infinitely (there's an internal counter to self-check this situation and panic though), and that's exactly what is demonstrated by the test. To fix such situation, first of all, add the test case to tests/data/parser/{err,fuzz-failures}. Then, run ``` RUST_BACKTRACE=short cargo test --package libsyntax2 ```` to verify that parser indeed panics, and to get an idea what grammar production is the culprit (look for `_list` functions!). In this case, I see ``` 10: libsyntax2::grammar::expressions::atom::match_arm_list at crates/libsyntax2/src/grammar/expressions/atom.rs:309 ``` and that's look like it might be a culprit. I verify it by adding `eprintln!("loopy {:?}", p.current());` and indeed I see that this is printed repeatedly. Diagnosing this a bit shows that the problem is that `pattern::pattern` function does not consume anything if the next token is `let`. That is a good default to make cases like ``` let let foo = 92; ``` where the user hasn't typed the pattern yet, to parse in a reasonable they correctly. For match arms, pretty much the single thing we expect is a pattern, so, for a fix, I introduce a special variant of pattern that does not do recovery.
* simplifyAleksey Kladov2018-09-082-7/+7
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* Don't get stuck in tuple exprsAleksey Kladov2018-09-081-0/+4
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* fix stuck parserAleksey Kladov2018-09-082-2/+11
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* fix labled expressionsAleksey Kladov2018-09-081-6/+16
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* add impl works with lifetimesAleksey Kladov2018-08-281-3/+4
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* better recovery for exprsAleksey Kladov2018-08-281-1/+4
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* Fix error blocksAleksey Kladov2018-08-272-0/+5
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* move scopes to fileAleksey Kladov2018-08-271-2/+2
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* Support if-let in scopesAleksey Kladov2018-08-271-1/+3
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* Require semi after exprsAleksey Kladov2018-08-251-3/+8
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* fix assertione error on block parsingAleksey Kladov2018-08-252-6/+5
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* start incremental reparseAleksey Kladov2018-08-251-1/+1
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* parameter parsing does not destroy blocksAleksey Kladov2018-08-242-2/+2
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* nodes for blocksAleksey Kladov2018-08-242-62/+78
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* Labeled expressionsAleksey Kladov2018-08-241-16/+45
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* break&continueAleksey Kladov2018-08-241-1/+38
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* renamesAleksey Kladov2018-08-242-2/+2
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* SimplifyAleksey Kladov2018-08-231-28/+26
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* full range exprAleksey Kladov2018-08-141-1/+5
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* Qualified pathsAleksey Kladov2018-08-132-2/+2
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* Fix some more bugsAleksey Kladov2018-08-131-1/+3
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* Optional patterns in trait methodsAleksey Kladov2018-08-131-1/+1
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* organizizeAleksey Kladov2018-08-102-0/+727