Avoid parsing Eof during recovery for incomplete path.

See #542

Author: cristianoc

src/res_core.ml

@@ -710,21 +710,25 @@ let parseValuePath p =
       Longident.Ldot (path, "_")
   in
   let ident = match p.Parser.token with
-  | Lident ident -> Longident.Lident ident
+  | Lident ident ->
+    Parser.next p;
+    Longident.Lident ident
   | Uident ident ->
     Parser.next p;
-    if p.Parser.token = Dot then (
+    let res = if p.Parser.token = Dot then (
       Parser.expect Dot p;
       aux p (Lident ident)  
     ) else (
       Parser.err p (Diagnostics.unexpected p.Parser.token p.breadcrumbs);
       Longident.Lident ident
-    )
+    ) in
+    if p.token <> Eof then Parser.next p;
+    res
   | token ->
     Parser.err p (Diagnostics.unexpected token p.breadcrumbs);
+    Parser.next p;
     Longident.Lident "_"
   in
-  Parser.next p;
   Location.mkloc ident (mkLoc startPos p.prevEndPos)
 
 let parseValuePathAfterDot p =

tests/parsing/errors/expressions/expected/id.res.txt

@@ -0,0 +1,9 @@
+
+  Syntax error!
+  tests/parsing/errors/expressions/id.res:1:5
+
+  1 │ n.R.
+
+  I'm not sure what to parse here when looking at "eof".
+
+;;n.R._

tests/parsing/errors/expressions/id.res

@@ -0,0 +1 @@
+n.R.