25 commits

Author	SHA1	Message	Date
darksv	64d07c1bd4	Implement reparsing for remaining blocks	2018-09-10 20:14:09 +02:00
Aleksey Kladov	a5c333c3ed	Fix yet another parser infinite loop ... 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.	2018-09-08 19:10:40 +03:00
Aleksey Kladov	749907d330	simplify	2018-09-08 10:38:53 +03:00
Aleksey Kladov	febbc9acdd	Don't get stuck in tuple exprs	2018-09-08 10:35:05 +03:00
Aleksey Kladov	bd3a26493f	fix stuck parser	2018-09-08 10:13:32 +03:00
Aleksey Kladov	44334f6f56	fix labled expressions	2018-09-08 09:18:42 +03:00
Aleksey Kladov	15f15d92eb	add impl works with lifetimes	2018-08-28 23:59:57 +03:00
Aleksey Kladov	2fa90e736b	better recovery for exprs	2018-08-28 11:12:42 +03:00
Aleksey Kladov	b79c8b6d8a	Fix error blocks	2018-08-27 21:10:02 +03:00
Aleksey Kladov	aaca7d003b	move scopes to file	2018-08-27 20:58:38 +03:00
Aleksey Kladov	07cbb7d73d	Support if-let in scopes	2018-08-27 12:22:09 +03:00
Aleksey Kladov	367e523442	Require semi after exprs	2018-08-25 16:04:47 +03:00
Aleksey Kladov	838820ad98	fix assertione error on block parsing	2018-08-25 13:21:43 +03:00
Aleksey Kladov	fed5727ea2	start incremental reparse	2018-08-25 13:17:54 +03:00
Aleksey Kladov	f104458d45	parameter parsing does not destroy blocks	2018-08-24 20:50:37 +03:00
Aleksey Kladov	7edab6ae6b	nodes for blocks	2018-08-24 19:27:30 +03:00
Aleksey Kladov	89e56c364f	Labeled expressions	2018-08-24 11:45:50 +03:00
Aleksey Kladov	719710a132	break&continue	2018-08-24 11:21:13 +03:00
Aleksey Kladov	a66c94af1b	renames	2018-08-24 02:14:10 +03:00
Aleksey Kladov	cf7d4a2a24	Simplify	2018-08-24 00:48:10 +03:00
Aleksey Kladov	de02d2891e	full range expr	2018-08-14 11:46:46 +03:00
Aleksey Kladov	49ab441024	Qualified paths	2018-08-13 23:54:00 +03:00
Aleksey Kladov	439e0fd32e	Fix some more bugs	2018-08-13 18:46:43 +03:00
Aleksey Kladov	7d0c9cf546	Optional patterns in trait methods	2018-08-13 18:40:47 +03:00
Aleksey Kladov	7c67612b8a	organizize	2018-08-10 22:33:29 +03:00