Merge #2827

2827: Fix array element attribute position r=matklad a=edwin0cheng

This PR fixed a bug which an ATTR node insert in the wrong place in array element. ~~And introduce `precede_next` for allow outer attributes to insert into a parsed `expr`.~~  

related #2783

Co-authored-by: Edwin Cheng <[email protected]>

3 files changed, 32 insertions, 8 deletions

diff --git a/crates/ra_parser/src/grammar/attributes.rs b/crates/ra_parser/src/grammar/attributes.rs
index f3158ade3..eeae37aef 100644
--- a/crates/ra_parser/src/grammar/attributes.rs
+++ b/crates/ra_parser/src/grammar/attributes.rs
@@ -8,6 +8,28 @@ pub(super) fn inner_attributes(p: &mut Parser) {
     }
 }
 
+pub(super) fn with_outer_attributes(
+    p: &mut Parser,
+    f: impl Fn(&mut Parser) -> Option<CompletedMarker>,
+) -> bool {
+    let am = p.start();
+    let has_attrs = p.at(T![#]);
+    attributes::outer_attributes(p);
+    let cm = f(p);
+    let success = cm.is_some();
+
+    match (has_attrs, cm) {
+        (true, Some(cm)) => {
+            let kind = cm.kind();
+            cm.undo_completion(p).abandon(p);
+            am.complete(p, kind);
+        }
+        _ => am.abandon(p),
+    }
+
+    success
+}
+
 pub(super) fn outer_attributes(p: &mut Parser) {
     while p.at(T![#]) {
         attribute(p, false)
diff --git a/crates/ra_parser/src/grammar/expressions.rs b/crates/ra_parser/src/grammar/expressions.rs
index 81d4f75f9..d733499d1 100644
--- a/crates/ra_parser/src/grammar/expressions.rs
+++ b/crates/ra_parser/src/grammar/expressions.rs
@@ -14,9 +14,9 @@ pub(super) enum StmtWithSemi {
 
 const EXPR_FIRST: TokenSet = LHS_FIRST;
 
-pub(super) fn expr(p: &mut Parser) -> BlockLike {
+pub(super) fn expr(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
     let r = Restrictions { forbid_structs: false, prefer_stmt: false };
-    expr_bp(p, r, 1).1
+    expr_bp(p, r, 1)
 }
 
 pub(super) fn expr_stmt(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index 4ac1d6334..700994e80 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -192,9 +192,8 @@ fn array_expr(p: &mut Parser) -> CompletedMarker {
     //    1,
     //    2,
     // ];
-    attributes::outer_attributes(p);
+    attributes::with_outer_attributes(p, |p| expr(p).0);
 
-    expr(p);
     if p.eat(T![;]) {
         expr(p);
         p.expect(T![']']);
@@ -212,12 +211,15 @@ fn array_expr(p: &mut Parser) -> CompletedMarker {
         //    #[cfg(test)]
         //    2,
         // ];
-        attributes::outer_attributes(p);
-        if !p.at_ts(EXPR_FIRST) {
-            p.error("expected expression");
+        if !attributes::with_outer_attributes(p, |p| {
+            if !p.at_ts(EXPR_FIRST) {
+                p.error("expected expression");
+                return None;
+            }
+            expr(p).0
+        }) {
             break;
         }
-        expr(p);
     }
     p.expect(T![']']);
     m.complete(p, ARRAY_EXPR)