SI-7854, SI-6768 better parsing/positioning in parser

The parser hole I found while working on the generated positions
serves as the umbrella for a host of improvements. Upgraded
positions assigned during some specific challenging situations mostly
involving the creation of synthetic trees, e.g. for comprehensions
and closures. While doing so improved some error messages.

Eliminated some of the most glaring duplication in the parser.
It's written like there is some payoff associated with being
spectacularly imperative. Not so far.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/files/neg/protected-constructors.check b/test/files/neg/protected-constructors.check
index f44d7db9b9..b636d076e4 100644
--- a/test/files/neg/protected-constructors.check
+++ b/test/files/neg/protected-constructors.check
@@ -1,12 +1,12 @@
 protected-constructors.scala:17: error: too many arguments for constructor Foo1: ()dingus.Foo1
     val foo1 = new Foo1("abc")
-               ^
+                   ^
 protected-constructors.scala:18: error: constructor Foo2 in class Foo2 cannot be accessed in object P
  Access to protected constructor Foo2 not permitted because
  enclosing object P in package hungus is not a subclass of
  class Foo2 in package dingus where target is defined
     val foo2 = new Foo2("abc")
-               ^
+                   ^
 protected-constructors.scala:19: error: class Foo3 in object Ding cannot be accessed in object dingus.Ding
  Access to protected class Foo3 not permitted because
  enclosing object P in package hungus is not a subclass of