SI-7143 Fix scanner docComment: docBuffer and docPos are initialized

in different places and as a result can get out of sync and as a result
the invariant that docComment has a position is broken.

1 files changed, 13 insertions, 21 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index 79f0bcf149..c05906c740 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -142,24 +142,16 @@ trait Scanners extends ScannersCommon {
     /** Should doc comments be built? */
     def buildDocs: Boolean = forScaladoc
 
-    /** buffer for the documentation comment
+    /** holder for the documentation comment
      */
-    var docBuffer: StringBuilder = null
-    var docPos: Position = null
+    var docComment: DocComment = null
 
-    /** Return current docBuffer and set docBuffer to null */
     def flushDoc: DocComment = {
-      val ret = if (docBuffer != null) DocComment(docBuffer.toString, docPos) else null
-      docBuffer = null
+      val ret = docComment
+      docComment = null
       ret
     }
 
-    /** add the given character to the documentation buffer
-     */
-    protected def putDocChar(c: Char) {
-      if (docBuffer ne null) docBuffer.append(c)
-    }
-
     protected def foundComment(value: String, start: Int, end: Int) = ()
     protected def foundDocComment(value: String, start: Int, end: Int) = ()
 
@@ -236,11 +228,11 @@ trait Scanners extends ScannersCommon {
           while (!sepRegions.isEmpty && sepRegions.head != RBRACE)
             sepRegions = sepRegions.tail
           if (!sepRegions.isEmpty) sepRegions = sepRegions.tail
-          docBuffer = null
+          docComment = null
         case RBRACKET | RPAREN =>
           if (!sepRegions.isEmpty && sepRegions.head == lastToken)
             sepRegions = sepRegions.tail
-          docBuffer = null
+          docComment = null
         case ARROW =>
           if (!sepRegions.isEmpty && sepRegions.head == lastToken)
             sepRegions = sepRegions.tail
@@ -546,7 +538,7 @@ trait Scanners extends ScannersCommon {
             nextChar()
           } while ((ch != CR) && (ch != LF) && (ch != SU))
         } else {
-          docBuffer = null
+          docComment = null
           var openComments = 1
           appendToComment()
           nextChar()
@@ -554,24 +546,23 @@ trait Scanners extends ScannersCommon {
           var buildingDocComment = false
           if (ch == '*' && buildDocs) {
             buildingDocComment = true
-            docBuffer = new StringBuilder("/**")
           }
           while (openComments > 0) {
             do {
               do {
                 if (ch == '/') {
-                  nextChar(); putDocChar(ch); appendToComment()
+                  nextChar(); appendToComment()
                   if (ch == '*') {
-                    nextChar(); putDocChar(ch); appendToComment()
+                    nextChar(); appendToComment()
                     openComments += 1
                   }
                 }
                 if (ch != '*' && ch != SU) {
-                  nextChar(); putDocChar(ch); appendToComment()
+                  nextChar(); appendToComment()
                 }
               } while (ch != '*' && ch != SU)
               while (ch == '*') {
-                nextChar(); putDocChar(ch); appendToComment()
+                nextChar(); appendToComment()
               }
             } while (ch != '/' && ch != SU)
             if (ch == '/') nextChar()
@@ -1310,7 +1301,8 @@ trait Scanners extends ScannersCommon {
     }
 
     override def foundDocComment(value: String, start: Int, end: Int) {
-      docPos = new RangePosition(unit.source, start, start, end)
+      val docPos = new RangePosition(unit.source, start, start, end)
+      docComment = new DocComment(value, docPos)
       unit.comment(docPos, value)
     }
   }