Commit Graph

522 Commits

Author SHA1 Message Date
Vadim Petrochenkov
55595c5616 ast: Always keep a NodeId in ast::Crate
This makes it more uniform with other expanded nodes
2022-01-05 17:09:37 +08:00
Jack Huey
4391a11537 Parse and suggest moving where clauses after equals for type aliases 2021-12-28 14:20:15 -05:00
bors
a41a6925ba Auto merge of #91957 - nnethercote:rm-SymbolStr, r=oli-obk
Remove `SymbolStr`

This was originally proposed in https://github.com/rust-lang/rust/pull/74554#discussion_r466203544. As well as removing the icky `SymbolStr` type, it allows the removal of a lot of `&` and `*` occurrences.

Best reviewed one commit at a time.

r? `@oli-obk`
2021-12-19 09:31:37 +00:00
Matthias Krüger
54e7946d0f
Rollup merge of #87901 - poliorcetics:pub-pub-pub, r=jackh726
Fix suggestion of additional `pub` when using `pub pub fn ...`

Fix #87694.

Marked as draft to start with because I want to explore doing the same fix for `const const fn` and other repeated-but-valid keywords.

`@rustbot` label A-diagnostics D-invalid-suggestion T-compiler
2021-12-18 08:16:25 +01:00
bors
c5ecc15704 Auto merge of #91962 - matthiaskrgr:rollup-2g082jw, r=matthiaskrgr
Rollup of 7 pull requests

Successful merges:

 - #91880 (fix clippy::single_char_pattern perf findings)
 - #91885 (Remove `in_band_lifetimes` from `rustc_codegen_ssa`)
 - #91898 (Make `TyS::is_suggestable` check for non-suggestable types structually)
 - #91915 (Add another regression test for unnormalized fn args with Self)
 - #91916 (Fix a bunch of typos)
 - #91918 (Constify `bool::then{,_some}`)
 - #91920 (Use `tcx.def_path_hash` in `ExistentialPredicate.stable_cmp`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
2021-12-15 12:41:42 +00:00
Matthias Krüger
9ca0bd518a
Rollup merge of #91880 - matthiaskrgr:clippy_perf_dec, r=jyn514
fix clippy::single_char_pattern perf findings
2021-12-15 10:56:58 +01:00
Nicholas Nethercote
056d48a2c9 Remove unnecessary sigils around Symbol::as_str() calls. 2021-12-15 17:32:14 +11:00
Jacob Pratt
d95f749f14
Stabilize destructuring_assignment 2021-12-14 22:38:51 -05:00
Nicholas Nethercote
8cddcd39ba Remove SymbolStr.
By changing `as_str()` to take `&self` instead of `self`, we can just
return `&str`. We're still lying about lifetimes, but it's a smaller lie
than before, where `SymbolStr` contained a (fake) `&'static str`!
2021-12-15 13:30:26 +11:00
Matthias Krüger
4b37cfc50c
Rollup merge of #91597 - r00ster91:lessthangreaterthan, r=oli-obk
Recover on invalid operators `<>` and `<=>`

Thanks to #89871 for showing me how to do this.
Next, I think it'd be nice to recover on `<=>` too, like #89871 intended, if this even works.
2021-12-14 20:47:27 +01:00
r00ster91
f194c9b26a Recover on invalid operators <> and <=> 2021-12-14 18:05:02 +01:00
Matthias Krüger
97e844a032 fix clippy::single_char_pattern perf findings 2021-12-14 12:40:28 +01:00
Alexis Bourget
be33ca7d5b Use Inherited Visibility instead of None when no vis is present 2021-12-13 22:41:42 +01:00
Alexis Bourget
b0806b2de9 Update test to new error message 2021-12-13 21:36:35 +01:00
Alexis Bourget
5c9950023b Suggest remove on const async const instead of const const async 2021-12-13 21:36:35 +01:00
Alexis Bourget
7bc8577d99 Fix broken span and related tests 2021-12-13 21:36:35 +01:00
Alexis Bourget
b88a612d9a Change error for pub in fn decl if already present 2021-12-13 21:36:32 +01:00
bors
753e569c9c Auto merge of #90207 - BoxyUwU:stabilise_cg_defaults, r=lcnr
Stabilise `feature(const_generics_defaults)`

`feature(const_generics_defaults)` is complete implementation wise and has a pretty extensive test suite so I think is ready for stabilisation.

needs stabilisation report and maybe an RFC 😅

r? `@lcnr`
cc `@rust-lang/project-const-generics`
2021-12-12 14:24:23 +00:00
Matthias Krüger
40988591ec
Rollup merge of #91625 - est31:remove_indexes, r=oli-obk
Remove redundant [..]s
2021-12-10 22:40:36 +01:00
Ellen
69d2d735bc remove feature gate and cleanup code 2021-12-10 19:20:31 +00:00
Matthias Krüger
8c94b2c375
Rollup merge of #91634 - terrarier2111:fix-recover-from-variant-ice, r=nagisa
Do not attempt to suggest help for overly malformed struct/function call

This fixes: https://github.com/rust-lang/rust/issues/91461
2021-12-09 05:08:33 +01:00
est31
15de4cbc4b Remove redundant [..]s 2021-12-09 00:01:29 +01:00
Matthias Krüger
d26fc45e5b
Rollup merge of #91337 - FabianWolff:issue-91227-misspelled-macro, r=nagisa
Add a suggestion if `macro_rules` is misspelled

Fixes #91227.
2021-12-08 23:18:04 +01:00
threadexception
b4c4bc09dd Do not attempt to suggest help for overly malformed struct/function call 2021-12-08 22:00:44 +01:00
Matthias Krüger
87f2c51dcd
Rollup merge of #91531 - notriddle:notriddle/issue-87647-expected-semicolon, r=estebank
Do not add `;` to expected tokens list when it's wrong

There's a few spots where semicolons are checked for to do error recovery, and should not be suggested (or checked for other stuff).

Fixes #87647
2021-12-08 11:08:59 +01:00
Michael Howell
6611567f9e Expect extern fn with no body when parsing
Also add a test case for inserting a semicolon on extern fns.

Without this fix, we got an error like this:

    error: expected one of `->`, `where`, or `{`, found `}`
     --> chk.rs:3:1
      |
    2 |   fn foo()
      |      ---  - expected one of `->`, `where`, or `{`
      |      |
      |      while parsing this `fn`
    3 | }
      | ^ unexpected token

Since this is inside an extern block, you're required to write function
prototypes with no body. This fixes a regression, and adds a test case
for it.
2021-12-06 11:16:46 -07:00
Michael Howell
61995926d2 Add better comments for FnParseMode 2021-12-06 11:16:02 -07:00
Matthias Krüger
29fe57def2
Rollup merge of #90022 - hkmatsumoto:self-upper-as-generic-parameter, r=jackh726
Explain why `Self` is invalid in generic parameters

Close #89985.

r? `@estebank`
2021-12-05 00:37:56 +01:00
Michael Howell
74437e477e Do not add ; to expected tokens list when it's wrong
There's a few spots where semicolons are checked for to do error recovery,
and should not be suggested (or checked for other stuff).

Fixes #87647
2021-12-04 11:05:30 -07:00
Matthias Krüger
dbb9e224af
Rollup merge of #91435 - FabianWolff:issue-91421-if-then, r=lcnr
Improve diagnostic for missing half of binary operator in `if` condition

Fixes #91421. I've also changed it so that it doesn't consume the `else` token in the error case, because it will try to consume it again afterwards, leading to this incorrect error message (where the `else` reported as missing is actually there):
```
error: expected one of `.`, `;`, `?`, `else`, or an operator, found `{`
 --> src/main.rs:4:12
  |
4 |     } else { 4 };
  |            ^ expected one of `.`, `;`, `?`, `else`, or an operator
```

r? `@lcnr`
2021-12-02 22:16:13 +01:00
Fabian Wolff
ba7374e517 Improve diagnostic for missing half of binary operator in if condition 2021-12-01 22:36:50 +01:00
Matthias Krüger
519a842c50
Rollup merge of #91313 - petrochenkov:cratexp, r=Aaron1011
expand: Turn `ast::Crate` into a first class expansion target

And stop creating a fake `mod` item for the crate root when expanding a crate, thus addressing FIXMEs left in https://github.com/rust-lang/rust/pull/82238, and making a step towards a proper support for crate-level macro attributes (cc #54726).

I haven't added token collection support for the whole crate in this PR, maybe later.
r? `@Aaron1011`
2021-12-01 20:57:43 +01:00
Esteban Kuber
c02710530c review comments: clean up 2021-11-29 18:39:08 +00:00
Fabian Wolff
b9b4f549a4 Add a suggestion if macro_rules is misspelled 2021-11-28 23:10:37 +01:00
Vadim Petrochenkov
141c6cc78e expand: Turn ast::Crate into a first class expansion target
And stop creating a fake `mod` item for the crate root when expanding a crate.
2021-11-28 15:48:55 +08:00
David Tolnay
87a7defa8e
Reject generic arguments on mod style interpolated path 2021-11-25 15:05:07 -08:00
David Tolnay
0cbb00f898
Let qpath contain NtTy: <$:ty as $:ty>::rest 2021-11-25 15:03:59 -08:00
Esteban Küber
d6e34ad108 When recovering from a : in a pattern, use adequate AST pattern 2021-11-25 18:40:29 +00:00
bors
23a436606b Auto merge of #88781 - estebank:emoji-idents, r=oli-obk
Tokenize emoji as if they were valid identifiers

In the lexer, consider emojis to be valid identifiers and reject
them later to avoid knock down parse errors.

Partially address #86102.
2021-11-25 08:16:08 +00:00
bors
c6eda7d8a7 Auto merge of #85346 - estebank:issue-84946, r=nagisa,varkor
Account for incorrect `impl Foo<const N: ty> {}` syntax

Fix #84946
2021-11-25 05:09:51 +00:00
Esteban Kuber
505b09e326 Tweak span and add more tests 2021-11-24 22:04:52 +00:00
Esteban Küber
7190bc3097 Account for incorrect impl Foo<const N: ty> {} syntax
Fix #84946
2021-11-24 20:02:09 +00:00
bors
de4b242e1e Auto merge of #91149 - notriddle:notriddle/rustdoc-doctest-semicolon, r=jyn514
fix(doctest): detect extern crate items in statement doctests

This partially reverts #91026, because rustdoc needs to detect the extern statements, even when they appear inside implicit `main()`. It does not entirely revert it, so the old bug is still fixed, by duplicating some of the logic from `parse_mod` instead of trying to use it directly.

Fixes #91134
2021-11-23 23:48:55 +00:00
Esteban Kuber
d68add9ecc review comment: plural of emoji is emoji 2021-11-23 20:36:19 +00:00
Esteban Kuber
21224e6ee0 Account for confusable codepoints when recovering emoji identifiers 2021-11-23 20:36:19 +00:00
Esteban Kuber
5a68abb094 Tokenize emoji as if they were valid indentifiers
In the lexer, consider emojis to be valid identifiers and reject
them later to avoid knock down parse errors.
2021-11-23 20:35:07 +00:00
Michael Howell
bff1645bdb fix(doctest): detect extern crate items in statement doctests
This partially reverts #91026, because rustdoc needs to detect the extern statements,
even when they appear inside implicit `main()`. It does not entirely revert it,
so the old bug is still fixed, by duplicating some of the logic from `parse_mod`
instead of trying to use it directly.

Fixes #91134
2021-11-22 19:47:58 -07:00
Gary Guo
6d61d87b22 Split inline const to two feature gates 2021-11-22 22:17:03 +00:00
Matthias Krüger
3d4f3ee71d
Rollup merge of #90994 - Badel2:issue-90993, r=estebank
Fix ICE `#90993`: add missing call to cancel

Fix #90993
2021-11-20 22:33:49 +01:00
threadexception
5f6059d9a2 Fix float ICE
Co-authored-by: Esteban Kuber <estebank@users.noreply.github.com>
2021-11-20 16:41:36 +01:00
Badel2
77a105c91f Fix ICE #90993: add missing call to cancel 2021-11-20 14:32:25 +01:00
5225225
09e59c2875 Inline printable function 2021-11-16 08:06:31 +00:00
5225225
52199c93bb Suggest removing the non-printing characters 2021-11-16 08:06:30 +00:00
5225225
de05d3ec31 Print full char literal on error if any are non-printing 2021-11-16 08:06:30 +00:00
Vadim Petrochenkov
6655727041 rustc_feature: Convert BuiltinAttribute from tuple to a struct 2021-11-12 20:15:14 +08:00
Vadim Petrochenkov
2834f57c45 ast: Fix naming conventions in AST structures
TraitKind -> Trait
TyAliasKind -> TyAlias
ImplKind -> Impl
FnKind -> Fn

All `*Kind`s in AST are supposed to be enums.

Tuple structs are converted to braced structs for the types above, and fields are reordered in syntactic order.

Also, mutable AST visitor now correctly visit spans in defaultness, unsafety, impl polarity and constness.
2021-11-07 21:38:17 +08:00
Hans Kratz
e339e4789f Remove now unused feature from rustc_parse 2021-11-04 23:40:59 +01:00
Hans Kratz
7885233df0 Optimize literal, doc comment lint as well, extract function. 2021-11-04 23:31:42 +01:00
Hans Kratz
a5b25a2cfa Create subslice as that leads to a smaller code size. 2021-11-04 17:03:13 +01:00
Hans Kratz
2d9f0e2c50 Optimize bidi character detection. 2021-11-04 12:01:26 +01:00
Pietro Albini
cdd3b8624f
fix formatting 2021-11-01 10:39:43 +01:00
Esteban Küber
c0b134582a
Lint against RTL unicode codepoints in literals and comments
Address CVE-2021-42574.
2021-10-31 13:14:04 +01:00
Yuki Okushi
8738d5d611
Rollup merge of #89257 - aDotInTheVoid:macro-error-2, r=estebank
Give better error for `macro_rules name`

follow up to #89221

r? ``@estebank``

``@rustbot`` modify labels: +A-diagnostics +A-parser
2021-10-22 19:42:43 +09:00
Hirochika Matsumoto
a72dd4a5b9 Explain why Self is invalid in generic parameters 2021-10-19 23:00:18 +09:00
Matthias Krüger
2fd765c1d9
Rollup merge of #89990 - petrochenkov:idempty, r=wesleywiser
rustc_span: `Ident::invalid` -> `Ident::empty`

The equivalent for `Symbol`s was renamed some time ago (`kw::Invalid` -> `kw::Empty`), and it makes sense to do the same thing for `Ident`s as well.
2021-10-18 08:13:30 +02:00
Matthias Krüger
5898c5d88e
Rollup merge of #89974 - est31:let_else_if_error, r=nagisa
Nicer error message if the user attempts to do let...else if

Gives a nice "conditional `else if` is not supported for `let...else`" error when encountering a `let...else if` pattern, as suggested in the [let...else tracking issue](https://github.com/rust-lang/rust/issues/87335#issuecomment-944846205).
2021-10-18 08:13:27 +02:00
est31
856541963c Nicer error message if the user attempts to do let...else if 2021-10-17 22:56:29 +02:00
Vadim Petrochenkov
a6808335d4 rustc_span: Ident::invalid -> Ident::empty
The equivalent for `Symbol`s was renamed some time ago (`kw::Invalid` -> `kw::Empty`), and it makes sense to do the same thing for `Ident`s.
2021-10-17 23:20:30 +03:00
r00ster91
3c1d55422a Some "parenthesis" and "parentheses" fixes 2021-10-17 12:04:01 +02:00
Matthias Krüger
ff6601e0fc some clippy::perf fixes 2021-10-07 22:31:33 +02:00
Fabian Wolff
079c075f24 Use TokenKind::similar_tokens() 2021-10-04 22:13:00 +02:00
Fabian Wolff
cf19131cb3 Try to recover from a => -> = or -> typo in a match arm 2021-10-03 14:14:35 +02:00
Nixon Enraght-Moony
729ff2d006 Give better error for macro_rules name 2021-10-01 22:47:39 +01:00
Manish Goregaokar
1708219940
Rollup merge of #89029 - notriddle:notriddle/issue-89013, r=estebank
feat(rustc_parse): recover from pre-RFC-2000 const generics syntax

Fixes #89013
2021-10-01 09:18:17 -07:00
Michael Howell
befdfb5c71 Improve error messages for bad type constraints
Co-authored-by: Esteban Kuber <esteban@kuber.com.ar>
2021-09-28 13:02:45 -07:00
Eric Huss
75f058dbfd Check for macros in built-in attributes that don't support them. 2021-09-25 09:03:15 -07:00
Eric Huss
5f8c571e50 Move malformed attribute code to a function and fix inner attribute suggestion.
Moving to a dedicated function in preparation for other validation.

The suggestion given didn't consider if it was an inner attribute.
2021-09-25 08:11:10 -07:00
Jubilee
6f31fa58fd
Rollup merge of #89221 - aDotInTheVoid:macro-error-1, r=estebank
Give better error for `macro_rules! name!`

r? ``@estebank``

``@rustbot`` modify labels: +A-diagnostics +A-parser
2021-09-24 11:40:17 -07:00
Nixon Enraght-Moony
ed3b751799 Give better error for macro_rules! name! 2021-09-24 16:21:34 +01:00
bors
a0648eab36 Auto merge of #88835 - FabianWolff:issue-88770, r=petrochenkov
Fix error recovery in format macro parsing

Fixes #88770. Basically, the assumption in the following comment is incorrect:
b69fe57261/compiler/rustc_builtin_macros/src/format.rs (L167-L172)

This is only true in the first iteration of the loop, when [`p.clear_expected_tokens()`](b69fe57261/compiler/rustc_builtin_macros/src/format.rs (L164)) is called. In subsequent iterations, `p.expected_tokens` won't be empty, so `p.expect()` won't actually call `unexpected_try_recover()`:
b69fe57261/compiler/rustc_parse/src/parser/mod.rs (L487-L498)

Instead, it will call `expect_one_of()`, which _can_ recover and return `Ok()`. This PR handles this case to fix the ICE in #88770.
2021-09-24 11:54:29 +00:00
Jubilee
5da2f460b3
Rollup merge of #89023 - Wardenfar:issue-85066, r=nagisa
Resolve issue : Somewhat confusing error with extended_key_value_attributes

Fixes #85066
2021-09-23 17:31:42 -07:00
the8472
5948a7b407
Rollup merge of #89046 - oli-obk:fix_oflo, r=estebank
"Fix" an overflow in byte position math

r? `@estebank`

help! I fixed the ICE only to brick the diagnostic.

I mean, it was wrong previously (using an already expanded macro span), but it is really bad now XD
2021-09-22 19:03:22 +02:00
the8472
c2cdba42b9
Rollup merge of #88795 - FabianWolff:issue-88684, r=wesleywiser
Print a note if a character literal contains a variation selector

Fixes #88684.
2021-09-21 22:53:58 +02:00
Oli Scherer
4281380717 Add some more tracing 2021-09-20 15:24:47 +00:00
Hirochika Matsumoto
21eff8f050 Suggest replacing braces for brackets on array-esque invalid block expr
Newcomers may write `{1, 2, 3}` for making arrays, and the current error
message is not informative enough to quickly convince them what is
needed to fix the error.
This PR implements a diagnostic for this case, and its output looks like
this:
```text
error: this code is interpreted as a block expression, not an array
 --> src/lib.rs:1:22
  |
1 |   const FOO: [u8; 3] = {
  |  ______________________^
2 | |     1, 2, 3
3 | | };
  | |_^
  |
  = note: to define an array, one would use square brackets instead of curly braces
help: try using [] instead of {}
  |
1 | const FOO: [u8; 3] = [
2 |     1, 2, 3
3 | ];
  |
```

Fix #87672
2021-09-19 20:01:23 +09:00
Theo
250a3e482f Resolve issue 85066
Fix : use struct_dummy

Fix different os messages
2021-09-19 10:53:49 +02:00
Guillaume Gomez
1b7896716e
Rollup merge of #87566 - JohnTitor:find-eqeq-on-assoc-type-bounds, r=estebank
Recover invalid assoc type bounds using `==`

Fix #87493
r? `@estebank`
2021-09-17 17:41:14 +02:00
Yuki Okushi
ee99bb3939
Apply review comments 2021-09-17 14:10:41 +09:00
Yuki Okushi
9342be5538
Recover invalid assoc type bounds using == 2021-09-17 14:02:00 +09:00
Yuki Okushi
e9bf73cb2b
Use multipart_suggestion 2021-09-17 13:39:26 +09:00
Yuki Okushi
58765d61ee
Emit clearer diagnostics for parens around for loop heads 2021-09-17 13:14:23 +09:00
Michael Howell
d8e9db0dcf feat(rustc_parse): recover from pre-RFC-2000 const generics syntax
Fixes #89013
2021-09-16 15:06:31 -07:00
Manish Goregaokar
2c7d48b900
Rollup merge of #88729 - estebank:struct-literal-using-parens, r=oli-obk
Recover from `Foo(a: 1, b: 2)`

Detect likely `struct` literal using parentheses as delimiters and emit
targeted suggestion instead of type ascription parse error.

Fix #61326.
2021-09-16 10:57:18 -07:00
Manish Goregaokar
fb2d7dff80
Rollup merge of #88775 - pnkfelix:revert-anon-union-parsing, r=davidtwco
Revert anon union parsing

Revert PR #84571 and #85515, which implemented anonymous union parsing in a manner that broke the context-sensitivity for the `union` keyword and thus broke stable Rust code.

Fix #88583.
2021-09-15 14:56:58 -07:00
Manish Goregaokar
4b568409ad
Rollup merge of #88690 - m-ou-se:macro-braces-dot-question-expr-parse, r=nagisa
Accept `m!{ .. }.method()` and `m!{ .. }?` statements.

This PR fixes something that I keep running into when using `quote!{}.into()` in a proc macro to convert the `proc_macro2::TokenStream` to a `proc_macro::TokenStream`:

Before:

```
error: expected expression, found `.`
 --> src/lib.rs:6:6
  |
4 |     quote! {
5 |         ...
6 |     }.into()
  |      ^ expected expression
```

After:
```
```
(No output, compiles fine.)

---

Context:

For expressions like `{ 1 }` and `if true { 1 } else { 2 }`, we accept them as full statements without a trailing `;`, which means the following is not accepted:

```rust
{ 1 } - 1 // error
```

since that is parsed as two statements: `{ 1 }` and `-1`. Syntactically correct, but the type of `{ 1 }` should be `()` as there is no `;`.

However, for specifically `.` and `?` after the `}`, we do [continue parsing it as an expression](13db8440bb/compiler/rustc_parse/src/parser/expr.rs (L864-L876)):

```rust
{ "abc" }.len(); // ok
```

For braced macro invocations, we do not do this:

```rust
vec![1, 2, 3].len(); // ok
vec!{1, 2, 3}.len(); // error
```

(It parses `vec!{1, 2, 3}` as a full statement, and then complains about `.len()` not being a valid expression.)

This PR changes this to also look for a `.` and `?` after a braced macro invocation. We can be sure the macro is an expression and not a full statement in those cases, since no statement can start with a `.` or `?`.
2021-09-15 14:56:57 -07:00
Esteban Kuber
ffc623ab93 review comment: move recovery code to its own function 2021-09-14 18:16:33 +00:00
bors
ec9a1bdc45 Auto merge of #88914 - GuillaumeGomez:rollup-h5svc6w, r=GuillaumeGomez
Rollup of 7 pull requests

Successful merges:

 - #88033 (Add links for primitives in "jump to definition" feature)
 - #88722 (Make `UnsafeCell::get_mut` const)
 - #88851 (Fix duplicate bounds for const_trait_impl)
 - #88859 (interpreter PointerArithmetic: use new Size helper methods)
 - #88885 (Fix jump def background)
 - #88894 (Improve error message for missing trait in trait impl)
 - #88896 (Reduce possibility of flaky tests)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
2021-09-14 08:46:22 +00:00
bors
9bb77da74d Auto merge of #87915 - estebank:fancy-spans, r=oli-obk
Use smaller spans for some structured suggestions

Use more accurate suggestion spans for

* argument parse error
* fully qualified path
* missing code block type
* numeric casts
2021-09-13 16:31:12 +00:00
Fabian Wolff
3f0e695919 Improve error message for missing trait in trait impl 2021-09-12 22:05:52 +02:00
bors
547d9374d2 Auto merge of #84373 - cjgillot:resolve-span, r=michaelwoerister,petrochenkov
Encode spans relative to the enclosing item

The aim of this PR is to avoid recomputing queries when code is moved without modification.

MCP at https://github.com/rust-lang/compiler-team/issues/443

This is achieved by :
1. storing the HIR owner LocalDefId information inside the span;
2. encoding and decoding spans relative to the enclosing item in the incremental on-disk cache;
3. marking a dependency to the `source_span(LocalDefId)` query when we translate a span from the short (`Span`) representation to its explicit (`SpanData`) representation.

Since all client code uses `Span`, step 3 ensures that all manipulations
of span byte positions actually create the dependency edge between
the caller and the `source_span(LocalDefId)`.
This query return the actual absolute span of the parent item.
As a consequence, any source code motion that changes the absolute byte position of a node will either:
- modify the distance to the parent's beginning, so change the relative span's hash;
- dirty `source_span`, and trigger the incremental recomputation of all code that
  depends on the span's absolute byte position.

With this scheme, I believe the dependency tracking to be accurate.

For the moment, the spans are marked during lowering.
I'd rather do this during def-collection,
but the AST MutVisitor is not practical enough just yet.
The only difference is that we attach macro-expanded spans
to their expansion point instead of the macro itself.
2021-09-11 23:35:28 +00:00