SI-8173 add support for patterns like init :+ last to quasiquotes

Adds support for patterns like:

  val q"{ ..$init; $last }" = q"{ a; b; c }"
  // init == List(q"a", q"b")
  // last == q"c"

Which under the hood get compiled as `:+` patterns:

  SyntacticBlock(init :+ last)

1 files changed, 26 insertions, 25 deletions

diff --git a/src/reflect/scala/reflect/internal/StdNames.scala b/src/reflect/scala/reflect/internal/StdNames.scala
index 28d799ea0c..53475be479 100644
--- a/src/reflect/scala/reflect/internal/StdNames.scala
+++ b/src/reflect/scala/reflect/internal/StdNames.scala
@@ -822,31 +822,32 @@ trait StdNames {
     def newLazyValSlowComputeName(lzyValName: Name) = lzyValName append LAZY_SLOW_SUFFIX
 
     // ASCII names for operators
-    val ADD      = encode("+")
-    val AND      = encode("&")
-    val ASR      = encode(">>")
-    val CONS     = encode("::")
-    val DIV      = encode("/")
-    val EQ       = encode("==")
-    val EQL      = encode("=")
-    val GE       = encode(">=")
-    val GT       = encode(">")
-    val HASHHASH = encode("##")
-    val LE       = encode("<=")
-    val LSL      = encode("<<")
-    val LSR      = encode(">>>")
-    val LT       = encode("<")
-    val MINUS    = encode("-")
-    val MOD      = encode("%")
-    val MUL      = encode("*")
-    val NE       = encode("!=")
-    val OR       = encode("|")
-    val PLUS     = ADD    // technically redundant, but ADD looks funny with MINUS
-    val PLUSPLUS = encode("++")
-    val SUB      = MINUS  // ... as does SUB with PLUS
-    val XOR      = encode("^")
-    val ZAND     = encode("&&")
-    val ZOR      = encode("||")
+    val ADD       = encode("+")
+    val AND       = encode("&")
+    val ASR       = encode(">>")
+    val CONS      = encode("::")
+    val COLONPLUS = encode(":+")
+    val DIV       = encode("/")
+    val EQ        = encode("==")
+    val EQL       = encode("=")
+    val GE        = encode(">=")
+    val GT        = encode(">")
+    val HASHHASH  = encode("##")
+    val LE        = encode("<=")
+    val LSL       = encode("<<")
+    val LSR       = encode(">>>")
+    val LT        = encode("<")
+    val MINUS     = encode("-")
+    val MOD       = encode("%")
+    val MUL       = encode("*")
+    val NE        = encode("!=")
+    val OR        = encode("|")
+    val PLUS      = ADD    // technically redundant, but ADD looks funny with MINUS
+    val PLUSPLUS  = encode("++")
+    val SUB       = MINUS  // ... as does SUB with PLUS
+    val XOR       = encode("^")
+    val ZAND      = encode("&&")
+    val ZOR       = encode("||")
 
     // unary operators
     val UNARY_~ = encode("unary_~")