Merge #692

692: [WIP] Correctly parse attributes  r=matklad a=DJMcNab

Reference - https://doc.rust-lang.org/reference/attributes.html
This fixes/investigates inner attributes for:

- [x] `impl` blocks
- [x] `extern` blocks
- [x] `fn`s (fixes #689)
- [x] `mod`s (already supported)
- [x] 'block expressions' (the long text just describes all 'blocks' used as statements)

This also investigates/fixes outer attributes for:

- [ ] 'most statements' (see also: #685, https://doc.rust-lang.org/reference/expressions.html#expression-attributes)
- [x] Enum variants, Struct and Union fields (Fixed in #507)
- [ ] 'Match expression arms' (@matklad can you provide a test case which explains what this means?)
- [ ] 'Generic lifetime or type parameters'
- [ ] 'Elements of array expressions, tuple expressions, call expressions, tuple-style struct and enum variant expressions'
- [ ] 'The tail expression of block expressions'

Co-authored-by: DJMcNab <[email protected]>

1 files changed, 4 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/yellow/syntax_error.rs b/crates/ra_syntax/src/yellow/syntax_error.rs
index 534f3511e..c52c44cc3 100644
--- a/crates/ra_syntax/src/yellow/syntax_error.rs
+++ b/crates/ra_syntax/src/yellow/syntax_error.rs
@@ -94,6 +94,7 @@ pub enum SyntaxErrorKind {
     UnicodeEscapeOutOfRange,
     UnclosedString,
     InvalidSuffix,
+    InvalidBlockAttr,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -136,6 +137,9 @@ impl fmt::Display for SyntaxErrorKind {
             UnicodeEscapeOutOfRange => write!(f, "Unicode escape code should be at most 0x10FFFF"),
             UnclosedString => write!(f, "Unclosed string literal"),
             InvalidSuffix => write!(f, "Invalid literal suffix"),
+            InvalidBlockAttr => {
+                write!(f, "A block in this position cannot accept inner attributes")
+            }
             ParseError(msg) => write!(f, "{}", msg.0),
         }
     }