Fix for a bug in CharArrayReader which made tri...

Fix for a bug in CharArrayReader which made triple quoted strings
fail to parse sometimes. Note: when the temptation strikes to adjust
for special cases by letting the regular case happen and subsequently
attempting to fix the ball of mutation by selectively applying what
seems like the inverse operation, please consider the possibility that
this is not the optimal approach. Closes SI-4785, no review.

Author: paulp

src/compiler/scala/tools/nsc/ast/parser/Scanners.scala

@@ -346,10 +346,7 @@ trait Scanners extends ScannersCommon {
             nextChar()
             if (ch == '\"') {
               nextRawChar()
-              val saved = lineStartOffset
               getMultiLineStringLit()
-              if (lineStartOffset != saved) // ignore linestarts within a multi-line string
-                lastLineStartOffset = saved
             } else {
               token = STRINGLIT
               strVal = ""

src/compiler/scala/tools/nsc/util/CharArrayReader.scala

@@ -47,7 +47,10 @@ abstract class CharArrayReader { self =>
     }
   }
 
-  /** Advance one character, leaving CR;LF pairs intact */
+  /** Advance one character, leaving CR;LF pairs intact.
+   *  This is for use in multi-line strings, so there are no
+   *  "potential line ends" here.
+   */
   final def nextRawChar() {
     if (charOffset >= buf.length) {
       ch = SU
@@ -56,7 +59,6 @@ abstract class CharArrayReader { self =>
       ch = c
       charOffset += 1
       if (c == '\\') potentialUnicode()
-      else if (c < ' ') potentialLineEnd()
     }
   }
 

test/files/run/triple-quoted-expr.check

@@ -0,0 +1,5 @@
+
+hi
+hi
+
+hi

test/files/run/triple-quoted-expr.scala

@@ -0,0 +1,26 @@
+class A {
+  def f1 = {
+    val x = 5
+
+"""
+hi"""
+  }
+  def f2 = {
+    val x = 5
+
+    """hi"""
+  }
+  def f3 = {
+    val x = 5
+
+    "\nhi"
+  }
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val x = new A
+    import x._
+    List(f1, f2, f3) foreach println
+  }
+}