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2020-10-22Don't create an empty `LazyTokenStream`Aaron Hill-19/+25
2020-10-21Unconditionally capture tokens for attributes.Aaron Hill-99/+87
This allows us to avoid synthesizing tokens in `prepend_attr`, since we have the original tokens available. We still need to synthesize tokens when expanding `cfg_attr`, but this is an unavoidable consequence of the syntax of `cfg_attr` - the user does not supply the `#` and `[]` tokens that a `cfg_attr` expands to.
2020-10-21Auto merge of #77250 - Aaron1011:feature/flat-token-collection, r=petrochenkovbors-156/+171
Rewrite `collect_tokens` implementations to use a flattened buffer Instead of trying to collect tokens at each depth, we 'flatten' the stream as we go allong, pushing open/close delimiters to our buffer just like regular tokens. One capturing is complete, we reconstruct a nested `TokenTree::Delimited` structure, producing a normal `TokenStream`. The reconstructed `TokenStream` is not created immediately - instead, it is produced on-demand by a closure (wrapped in a new `LazyTokenStream` type). This closure stores a clone of the original `TokenCursor`, plus a record of the number of calls to `next()/next_desugared()`. This is sufficient to reconstruct the tokenstream seen by the callback without storing any additional state. If the tokenstream is never used (e.g. when a captured `macro_rules!` argument is never passed to a proc macro), we never actually create a `TokenStream`. This implementation has a number of advantages over the previous one: * It is significantly simpler, with no edge cases around capturing the start/end of a delimited group. * It can be easily extended to allow replacing tokens an an arbitrary 'depth' by just using `Vec::splice` at the proper position. This is important for PR #76130, which requires us to track information about attributes along with tokens. * The lazy approach to `TokenStream` construction allows us to easily parse an AST struct, and then decide after the fact whether we need a `TokenStream`. This will be useful when we start collecting tokens for `Attribute` - we can discard the `LazyTokenStream` if the parsed attribute doesn't need tokens (e.g. is a builtin attribute). The performance impact seems to be neglibile (see https://github.com/rust-lang/rust/pull/77250#issuecomment-703960604). There is a small slowdown on a few benchmarks, but it only rises above 1% for incremental builds, where it represents a larger fraction of the much smaller instruction count. There a ~1% speedup on a few other incremental benchmarks - my guess is that the speedups and slowdowns will usually cancel out in practice.
2020-10-21Rollup merge of #78118 - spastorino:inline-const-followups, r=petrochenkovYuki Okushi-1/+5
Inline const followups r? @petrochenkov Follow ups of #77124
2020-10-19Allow NtBlock to parse on check inline const next tokenSantiago Pastorino-1/+5
2020-10-19Rewrite `collect_tokens` implementations to use a flattened bufferAaron Hill-156/+171
Instead of trying to collect tokens at each depth, we 'flatten' the stream as we go allong, pushing open/close delimiters to our buffer just like regular tokens. One capturing is complete, we reconstruct a nested `TokenTree::Delimited` structure, producing a normal `TokenStream`. The reconstructed `TokenStream` is not created immediately - instead, it is produced on-demand by a closure (wrapped in a new `LazyTokenStream` type). This closure stores a clone of the original `TokenCursor`, plus a record of the number of calls to `next()/next_desugared()`. This is sufficient to reconstruct the tokenstream seen by the callback without storing any additional state. If the tokenstream is never used (e.g. when a captured `macro_rules!` argument is never passed to a proc macro), we never actually create a `TokenStream`. This implementation has a number of advantages over the previous one: * It is significantly simpler, with no edge cases around capturing the start/end of a delimited group. * It can be easily extended to allow replacing tokens an an arbitrary 'depth' by just using `Vec::splice` at the proper position. This is important for PR #76130, which requires us to track information about attributes along with tokens. * The lazy approach to `TokenStream` construction allows us to easily parse an AST struct, and then decide after the fact whether we need a `TokenStream`. This will be useful when we start collecting tokens for `Attribute` - we can discard the `LazyTokenStream` if the parsed attribute doesn't need tokens (e.g. is a builtin attribute). The performance impact seems to be neglibile (see https://github.com/rust-lang/rust/pull/77250#issuecomment-703960604). There is a small slowdown on a few benchmarks, but it only rises above 1% for incremental builds, where it represents a larger fraction of the much smaller instruction count. There a ~1% speedup on a few other incremental benchmarks - my guess is that the speedups and slowdowns will usually cancel out in practice.
2020-10-19Avoid cloning the contents of a `TokenStream` in a few placesAaron Hill-5/+5
2020-10-18Remove redundant 'static in the compilerest31-1/+1
2020-10-16Parse inline const patternsSantiago Pastorino-0/+3
2020-10-16Parse inline const expressionsSantiago Pastorino-3/+26
2020-10-16Rollup merge of #77780 - calebcartwright:cast-expr-attr-span, r=oli-obkDylan DPC-7/+17
rustc_parse: fix spans on cast and range exprs with attrs Currently the span for cast and range expressions does not include the span of attributes associated to the lhs which is causing some issues for us in rustfmt. ```rust fn foo() -> i64 { #[attr] 1u64 as i64 } fn bar() -> Range<i32> { #[attr] 1..2 } ``` This corrects the span for cast and range expressions to fully include the span of child nodes
2020-10-15fix off-by-one in parameter spansAndy Russell-1/+1
2020-10-15Rollup merge of #77739 - est31:remove_unused_code, r=petrochenkov,varkorYuki Okushi-16/+0
Remove unused code Rustc has a builtin lint for detecting unused code inside a crate, but when an item is marked `pub`, the code, even if unused inside the entire workspace, is never marked as such. Therefore, I've built [warnalyzer](https://github.com/est31/warnalyzer) to detect unused items in a cross-crate setting. Closes https://github.com/est31/warnalyzer/issues/2
2020-10-14Remove unused code from remaining compiler cratesest31-16/+0
2020-10-12rustc_parse: correct span on range expr with attrsCaleb Cartwright-1/+1
2020-10-12rustc_parse: correct span on cast expr with attrsCaleb Cartwright-6/+16
2020-10-11Remove unused importAaron Hill-1/+1
2020-10-11Add `relaxed_delim_match` parameterAaron Hill-16/+53
2020-10-11Allow skipping extra paren insertion during AST pretty-printingAaron Hill-7/+30
Fixes #74616 Makes progress towards #43081 Unblocks PR #76130 When pretty-printing an AST node, we may insert additional parenthesis to ensure that precedence is properly preserved in code we output. However, the proc macro implementation relies on comparing a pretty-printed AST node to the captured `TokenStream`. Inserting extra parenthesis changes the structure of the reparsed `TokenStream`, making the comparison fail. This PR refactors the AST pretty-printing code to allow skipping the insertion of additional parenthesis. Several freestanding methods are moved to trait methods on `PrintState`, which keep track of an internal `insert_extra_parens` flag. This flag is normally `true`, but we expose a public method which allows pretty-printing a nonterminal with `insert_extra_parens = false`. To avoid changing the public interface of `rustc_ast_pretty`, the freestanding `_to_string` methods are changed to delegate to a newly-crated `State`. The main pretty-printing code is moved to a new `state` module to ensure that it does not accidentally call any of these public helper functions (instead, the internal functions with the same name should be used).
2020-10-11rustc_parse: More precise spans for `tuple.0.0`Vadim Petrochenkov-7/+33
2020-10-07Detect blocks that could be struct expr bodiesEsteban Küber-15/+125
This approach lives exclusively in the parser, so struct expr bodies that are syntactically correct on their own but are otherwise incorrect will still emit confusing errors, like in the following case: ```rust fn foo() -> Foo { bar: Vec::new() } ``` ``` error[E0425]: cannot find value `bar` in this scope --> src/file.rs:5:5 | 5 | bar: Vec::new() | ^^^ expecting a type here because of type ascription error[E0214]: parenthesized type parameters may only be used with a `Fn` trait --> src/file.rs:5:15 | 5 | bar: Vec::new() | ^^^^^ only `Fn` traits may use parentheses error[E0107]: wrong number of type arguments: expected 1, found 0 --> src/file.rs:5:10 | 5 | bar: Vec::new() | ^^^^^^^^^^ expected 1 type argument ``` If that field had a trailing comma, that would be a parse error and it would trigger the new, more targetted, error: ``` error: struct literal body without path --> file.rs:4:17 | 4 | fn foo() -> Foo { | _________________^ 5 | | bar: Vec::new(), 6 | | } | |_^ | help: you might have forgotten to add the struct literal inside the block | 4 | fn foo() -> Foo { Path { 5 | bar: Vec::new(), 6 | } } | ``` Partially address last part of #34255.
2020-10-07Auto merge of #77595 - petrochenkov:asmident, r=oli-obkbors-1/+1
builtin_macros: Fix use of interpolated identifiers in `asm!` Fixes https://github.com/rust-lang/rust/issues/77584
2020-10-06rustc_parse: Make `Parser::unexpected` public and use it in built-in macrosVadim Petrochenkov-1/+1
2020-10-05Fix span for unicode escape suggestion.Eric Huss-3/+2
2020-10-02Rollup merge of #77444 - estebank:pat-field-label, r=davidtwcoJonas Schievink-1/+2
Fix span for incorrect pattern field and add label Address #73750.
2020-10-02Fix span for incorrect pattern field and add labelEsteban Küber-1/+2
2020-09-28Fix recursive nonterminal expansion during pretty-print/reparse checkAaron Hill-23/+34
Makes progress towards #43081 In PR #73084, we started recursively expanded nonterminals during the pretty-print/reparse check, allowing them to be properly compared against the reparsed tokenstream. Unfortunately, the recursive logic in that PR only handles the case where a nonterminal appears inside a `TokenTree::Delimited`. If a nonterminal appears directly in the expanded tokens of another nonterminal, the inner nonterminal will not be expanded. This PR fixes the recursive expansion of nonterminals, ensuring that they are expanded wherever they occur.
2020-09-26pretty-print-reparse hack: Remove an impossible caseVadim Petrochenkov-4/+1
Delimiters cannot appear as isolated tokens in a token stream
2020-09-26pretty-print-reparse hack: Rename some variables for clarityVadim Petrochenkov-16/+21
2020-09-23Rollup merge of #76994 - yuk1ty:fix-small-typo, r=estebankDylan DPC-1/+1
fix small typo in docs and comments Fixed `the the` to `the`, as far as I found.
2020-09-22Suggest async {} for async || {}Andy Weiss-4/+5
Fixes #76011 This adds support for adding help diagnostics to the feature gating checks and then uses it for the async_closure gate to add the extra bit of help information as described in the issue.
2020-09-21Rollup merge of #76888 - matthiaskrgr:clippy_single_match_2, r=Dylan-DPCecstatic-morse-6/+3
use if let instead of single match arm expressions use if let instead of single match arm expressions to compact code and reduce nesting (clippy::single_match)
2020-09-21Don't use `zip` to compare iterators during pretty-print hackAaron Hill-8/+5
If the right-hand iterator has exactly one more element than the left-hand iterator, then both iterators will be fully consumed, but the extra element will never be compared.
2020-09-21fix typo in docs and commentsyuk1ty-1/+1
2020-09-20use if let instead of single match arm expressions to compact code and ↵Matthias Krüger-6/+3
reduce nesting (clippy::single_match)
2020-09-17Remove redundant #![feature(...)] 's from compiler/est31-1/+0
2020-09-15improve diagnostics for lifetime after `&mut`SNCPlay42-1/+27
2020-09-15Auto merge of #76171 - estebank:turbofish-the-revenge, r=davidtwcobors-6/+66
Detect turbofish with multiple type params missing leading `::` Fix #76072.
2020-09-14Detect turbofish with multiple type params missing leading `::`Esteban Küber-6/+66
Fix #76072.
2020-09-13Auto merge of #76598 - ad-anssi:diagnostic_errors_fix, r=estebankbors-1/+5
Fixing memory exhaustion when formatting short code suggestion Details can be found in issue #76597. This PR replaces substractions with `saturating_sub`'s to avoid usize wrapping leading to memory exhaustion when formatting short suggestion messages.
2020-09-13Auto merge of #76585 - Aaron1011:ignore-vert-plus, r=petrochenkovbors-0/+6
Ignore `|` and `+` tokens during proc-macro pretty-print check Fixes #76182 This is an alternative to PR #76188 These tokens are not preserved in the AST in certain cases (e.g. a leading `|` in a pattern or a trailing `+` in a trait bound). This PR ignores them entirely during the pretty-print/reparse check to avoid spuriously using the re-parsed tokenstream.
2020-09-11repairing broken error message and rustfix application for the new testAurélien Deharbe-1/+5
case
2020-09-10Attach tokens to `ast::Stmt`Aaron Hill-5/+22
We currently only attach tokens when parsing a `:stmt` matcher for a `macro_rules!` macro. Proc-macro attributes on statements are still unstable, and need additional work.
2020-09-10Attach `TokenStream` to `ast::Visibility`Aaron Hill-12/+40
A `Visibility` does not have outer attributes, so we only capture tokens when parsing a `macro_rules!` matcher
2020-09-10Attach `TokenStream` to `ast::Path`Aaron Hill-6/+18
2020-09-10Attach tokens to `NtMeta` (`ast::AttrItem`)Aaron Hill-2/+10
An `AttrItem` does not have outer attributes, so we only capture tokens when parsing a `macro_rules!` matcher
2020-09-10Collect tokens when handling `:literal` matcherAaron Hill-2/+10
An `NtLiteral` just wraps an `Expr`, so we don't need to add a new `tokens` field to an AST struct.
2020-09-10Attach `TokenStream` to `ast::Ty`Aaron Hill-6/+24
A `Ty` does not have outer attributes, so we only capture tokens when parsing a `macro_rules!` matcher
2020-09-10Attach `TokenStream` to `ast::Block`Aaron Hill-2/+10
A `Block` does not have outer attributes, so we only capture tokens when parsing a `macro_rules!` matcher
2020-09-10Ignore `|` and `+` tokens during proc-macro pretty-print checkAaron Hill-0/+6
Fixes #76182 This is an alternative to PR #76188 These tokens are not preserved in the AST in certain cases (e.g. a leading `|` in a pattern or a trailing `+` in a trait bound). This PR ignores them entirely during the pretty-print/reparse check to avoid spuriously using the re-parsed tokenstream.