sourcepath: Handle end markers in outline parsing

Previously, outline parsing would have failed on indent1.scala with:

7 |  end inner
  |  ^
  |  misaligned end marker

because `OutlineParserCommon#skipBraces` does not update
`in.openEndMarkers`, but calls `in.nextToken` which eventually calls
`in.skipEndMarker` which checks that end markers are aligned.

This commit fixes this by adding a boolean in the scanner to turn off
end marker checks, this is used by the outline parser when skipping over
code.

Author: smarter

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -156,12 +156,17 @@ object Parsers {
     def skipBraces(): Unit = {
       accept(if (in.token == INDENT) INDENT else LBRACE)
       var openBraces = 1
-      while (in.token != EOF && openBraces > 0)
-        skipBracesHook() getOrElse {
-          if (in.token == LBRACE || in.token == INDENT) openBraces += 1
-          else if (in.token == RBRACE || in.token == OUTDENT) openBraces -= 1
-          in.nextToken()
-        }
+      val savedCheckEndMarker = in.checkEndMarker
+      try
+        in.checkEndMarker = false
+        while (in.token != EOF && openBraces > 0)
+          skipBracesHook() getOrElse {
+            if (in.token == LBRACE || in.token == INDENT) openBraces += 1
+            else if (in.token == RBRACE || in.token == OUTDENT) openBraces -= 1
+            in.nextToken()
+          }
+      finally
+        in.checkEndMarker = savedCheckEndMarker
     }
   }
 

compiler/src/dotty/tools/dotc/parsing/Scanners.scala

@@ -54,6 +54,9 @@ object Scanners {
     /** the base of a number */
     var base: Int = 0
 
+    /** Set to false to disable end marker alignment checks, used for outline parsing. */
+    var checkEndMarker: Boolean = true
+
     def copyFrom(td: TokenData): Unit = {
       this.token = td.token
       this.offset = td.offset
@@ -331,10 +334,12 @@ object Scanners {
     def endMarkerScope[T](tag: EndMarkerTag)(op: => T): T =
       val saved = openEndMarkers
       openEndMarkers = (tag, currentRegion.indentWidth) :: openEndMarkers
-      try op finally openEndMarkers = saved
+      try op
+      finally openEndMarkers = saved
 
     /** If this token and the next constitute an end marker, skip them and check they
-     *  align with an opening construct with the same end marker tag.
+     *  align with an opening construct with the same end marker tag,
+     *  unless `checkEndMarker` is false.
      */
     protected def skipEndMarker(width: IndentWidth): Unit =
       if next.token == IDENTIFIER && next.name == nme.end then
@@ -348,8 +353,9 @@ object Scanners {
                 openEndMarkers = rest
                 checkAligned()
             case _ =>
-              lexical.println(i"misaligned end marker $tag, $width, $openEndMarkers")
-              errorButContinue("misaligned end marker", start)
+              if checkEndMarker
+                lexical.println(i"misaligned end marker $tag, $width, $openEndMarkers")
+                errorButContinue("misaligned end marker", start)
 
           val skipTo = lookahead.charOffset
           lookahead.nextToken()

tests/pos-special/sourcepath/outer/indent2.scala

@@ -0,0 +1,7 @@
+package outer
+import nested._
+
+object indent2 {
+  val x2: Int = indent1.inner.x
+  val y2: Int = indent1.y
+}

tests/pos-special/sourcepath/outer/nested/indent1.scala

@@ -0,0 +1,9 @@
+package outer
+package nested
+
+object indent1
+  object inner with
+    def x: Int = 1
+  end inner
+  val y: Int = 2
+end indent1