fix: Don't create empty path nodes

Author: Veykril

crates/parser/src/grammar.rs

@@ -242,7 +242,7 @@ fn opt_visibility(p: &mut Parser<'_>, in_tuple_field: bool) -> bool {
                 // struct MyStruct(pub ());
                 if !(in_tuple_field && matches!(p.nth(1), T![ident] | T![')'])) {
                     p.bump(T!['(']);
-                    paths::use_path(p);
+                    paths::vis_path(p);
                     p.expect(T![')']);
                 }
             }
@@ -252,7 +252,7 @@ fn opt_visibility(p: &mut Parser<'_>, in_tuple_field: bool) -> bool {
             T![in] => {
                 p.bump(T!['(']);
                 p.bump(T![in]);
-                paths::use_path(p);
+                paths::vis_path(p);
                 p.expect(T![')']);
             }
             _ => {}

crates/parser/src/grammar/generic_args.rs

@@ -168,10 +168,10 @@ pub(super) fn const_arg_expr(p: &mut Parser<'_>) {
             expressions::literal(p);
             lm.complete(p, PREFIX_EXPR);
         }
-        _ if paths::is_use_path_start(p) => {
+        _ if paths::is_path_start(p) => {
             // This shouldn't be hit by `const_arg`
             let lm = p.start();
-            paths::use_path(p);
+            paths::expr_path(p);
             lm.complete(p, PATH_EXPR);
         }
         _ => {

crates/parser/src/grammar/paths.rs

@@ -19,6 +19,10 @@ pub(super) fn use_path(p: &mut Parser<'_>) {
     path(p, Mode::Use);
 }
 
+pub(super) fn vis_path(p: &mut Parser<'_>) {
+    path(p, Mode::Vis);
+}
+
 pub(super) fn attr_path(p: &mut Parser<'_>) {
     path(p, Mode::Attr);
 }
@@ -44,13 +48,17 @@ enum Mode {
     Attr,
     Type,
     Expr,
+    Vis,
 }
 
-fn path(p: &mut Parser<'_>, mode: Mode) {
+fn path(p: &mut Parser<'_>, mode: Mode) -> Option<CompletedMarker> {
     let path = p.start();
-    path_segment(p, mode, true);
+    if path_segment(p, mode, true).is_none() {
+        path.abandon(p);
+        return None;
+    }
     let qual = path.complete(p, PATH);
-    path_for_qualifier(p, mode, qual);
+    Some(path_for_qualifier(p, mode, qual))
 }
 
 fn path_for_qualifier(
@@ -76,7 +84,7 @@ const EXPR_PATH_SEGMENT_RECOVERY_SET: TokenSet =
     items::ITEM_RECOVERY_SET.union(TokenSet::new(&[T![')'], T![,], T![let]]));
 const TYPE_PATH_SEGMENT_RECOVERY_SET: TokenSet = types::TYPE_RECOVERY_SET;
 
-fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) {
+fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) -> Option<CompletedMarker> {
     let m = p.start();
     // test qual_paths
     // type X = <A as B>::Output;
@@ -117,6 +125,7 @@ fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) {
                     Mode::Attr => {
                         items::ITEM_RECOVERY_SET.union(TokenSet::new(&[T![']'], T![=], T![#]]))
                     }
+                    Mode::Vis => items::ITEM_RECOVERY_SET.union(TokenSet::new(&[T![')']])),
                     Mode::Type => TYPE_PATH_SEGMENT_RECOVERY_SET,
                     Mode::Expr => EXPR_PATH_SEGMENT_RECOVERY_SET,
                 };
@@ -125,17 +134,17 @@ fn path_segment(p: &mut Parser<'_>, mode: Mode, first: bool) {
                     // test_err empty_segment
                     // use crate::;
                     m.abandon(p);
-                    return;
+                    return None;
                 }
             }
         };
     }
-    m.complete(p, PATH_SEGMENT);
+    Some(m.complete(p, PATH_SEGMENT))
 }
 
 fn opt_path_type_args(p: &mut Parser<'_>, mode: Mode) {
     match mode {
-        Mode::Use | Mode::Attr => {}
+        Mode::Use | Mode::Attr | Mode::Vis => {}
         Mode::Type => {
             // test typepathfn_with_coloncolon
             // type F = Start::(Middle) -> (Middle)::End;

crates/parser/src/parser.rs

@@ -327,10 +327,10 @@ impl Marker {
         self.bomb.defuse();
         let idx = self.pos as usize;
         if idx == p.events.len() - 1 {
-            match p.events.pop() {
-                Some(Event::Start { kind: TOMBSTONE, forward_parent: None }) => (),
-                _ => unreachable!(),
-            }
+            assert!(matches!(
+                p.events.pop(),
+                Some(Event::Start { kind: TOMBSTONE, forward_parent: None })
+            ));
         }
     }
 }

crates/parser/test_data/parser/inline/err/crate_visibility_empty_recover.rast

@@ -3,10 +3,7 @@ SOURCE_FILE
     VISIBILITY
       PUB_KW "pub"
       L_PAREN "("
-      PATH
-        PATH_SEGMENT
-          ERROR
-            R_PAREN ")"
+      R_PAREN ")"
     WHITESPACE " "
     STRUCT_KW "struct"
     WHITESPACE " "
@@ -15,4 +12,3 @@ SOURCE_FILE
     SEMICOLON ";"
   WHITESPACE "\n"
 error 4: expected identifier
-error 5: expected R_PAREN

crates/parser/test_data/parser/inline/err/meta_recovery.rast

@@ -4,7 +4,6 @@ SOURCE_FILE
     BANG "!"
     L_BRACK "["
     META
-      PATH
     R_BRACK "]"
   WHITESPACE "\n"
   ATTR
@@ -55,7 +54,6 @@ SOURCE_FILE
     L_BRACK "["
     META
       UNSAFE_KW "unsafe"
-      PATH
     R_BRACK "]"
   WHITESPACE "\n"
   ATTR
@@ -65,7 +63,6 @@ SOURCE_FILE
     META
       UNSAFE_KW "unsafe"
       WHITESPACE " "
-      PATH
       EQ "="
     R_BRACK "]"
   WHITESPACE "\n"
@@ -80,7 +77,7 @@ error 41: expected L_PAREN
 error 41: expected identifier
 error 41: expected R_PAREN
 error 52: expected L_PAREN
-error 53: expected identifier
+error 52: expected identifier
 error 54: expected expression
 error 54: expected expression
 error 54: expected R_PAREN