fix: make unterminated comments consume all input

Fixes #549

src/Lean/Parser/Basic.lean

@@ -724,7 +724,6 @@ def takeWhileFn (p : Char → Bool) : ParserFn :=
 @[inline] def takeWhile1Fn (p : Char → Bool) (errorMsg : String) : ParserFn :=
   andthenFn (satisfyFn p errorMsg) (takeWhileFn p)
 
-variable (startPos : String.Pos) in
 partial def finishCommentBlock (nesting : Nat) : ParserFn := fun c s =>
   let input := c.input
   let i     := s.pos
@@ -749,7 +748,7 @@ partial def finishCommentBlock (nesting : Nat) : ParserFn := fun c s =>
         else finishCommentBlock nesting c (s.setPos i)
     else finishCommentBlock nesting c (s.setPos i)
 where
-  eoi s := s.mkUnexpectedErrorAt "unterminated comment" startPos
+  eoi s := s.mkUnexpectedError "unterminated comment"
 
 /- Consume whitespace and comments -/
 partial def whitespace : ParserFn := fun c s =>
@@ -774,7 +773,7 @@ partial def whitespace : ParserFn := fun c s =>
         let i    := input.next i
         let curr := input.get i
         if curr == '-' then s -- "/--" doc comment is an actual token
-        else andthenFn (finishCommentBlock startPos 1) whitespace c (s.next input i)
+        else andthenFn (finishCommentBlock 1) whitespace c (s.next input i)
       else s
     else s
 

src/Lean/Parser/Term.lean

@@ -11,7 +11,7 @@ namespace Parser
 
 namespace Command
 def commentBody : Parser :=
-{ fn := rawFn (fun c s => finishCommentBlock s.pos 1 c s) (trailingWs := true) }
+{ fn := rawFn (finishCommentBlock 1) (trailingWs := true) }
 
 @[combinatorParenthesizer Lean.Parser.Command.commentBody] def commentBody.parenthesizer := PrettyPrinter.Parenthesizer.visitToken
 @[combinatorFormatter Lean.Parser.Command.commentBody] def commentBody.formatter := PrettyPrinter.Formatter.visitAtom Name.anonymous

tests/lean/interactive/unterminatedDocComment.lean

@@ -0,0 +1,9 @@
+/--
+def a1 := sorry
+def a2 := sorry
+def a3 := sorry
+...
+ -
+--^ insert: /
+--^ collectDiagnostics
+def a4 := 0

tests/lean/interactive/unterminatedDocComment.lean.expected.out

@@ -0,0 +1,6 @@
+{"textDocument": {"version": 2, "uri": "file://unterminatedDocComment.lean"},
+ "contentChanges":
+ [{"text": "/",
+   "range":
+   {"start": {"line": 5, "character": 2}, "end": {"line": 5, "character": 3}}}]}
+{"version": 2, "uri": "file://unterminatedDocComment.lean", "diagnostics": []}

tests/lean/tokenErrors.lean.expected.out

@@ -2,7 +2,4 @@ tokenErrors.lean:1:10: error: missing end of character literal
 tokenErrors.lean:2:9: error: invalid escape sequence
 tokenErrors.lean:3:7: error: unterminated string literal
 tokenErrors.lean:4:11: error: unterminated identifier escape
-tokenErrors.lean:6:0: error: unterminated comment
-tokenErrors.lean:7:0: error: unterminated comment
-tokenErrors.lean:7:1: error: unterminated comment
-tokenErrors.lean:7:0-7:1: error: unexpected command
+tokenErrors.lean:8:0: error: unterminated comment