Implicits to encourage more Name-dropping.

This creates implicits in cakes across the land from:

  String => TermName
  String => TypeName

And also from:

  Name => NameOps[Name]           // lower priority
  TermName => NameOps[TermName]
  TypeName => NameOps[TypeName]

What this is all about, using "drop" as a motivating example,
is that these should all work:

  "abc" drop 1                      // "bc": String
  ("abc": TermName) drop 1          // "bc": TermName
  ("abc": TypeName) drop 1          // "bc": TypeName
  (("abc": TypeName): Name) drop 1  // "bc": Name

But this should not:

  ("bc": Name)  // ambiguity error

This requires drop not being directly on Name; peer implicits
from String => TermName and String => TypeName; implicit
classes to install drop on TermName and TypeName; and a lower
priority implicit class to allow ops on Names.

Review by @xeno.by .

1 files changed, 6 insertions, 1 deletions

diff --git a/src/reflect/scala/reflect/internal/StdNames.scala b/src/reflect/scala/reflect/internal/StdNames.scala
index 72a99589d5..4070ad83c6 100644
--- a/src/reflect/scala/reflect/internal/StdNames.scala
+++ b/src/reflect/scala/reflect/internal/StdNames.scala
@@ -84,6 +84,9 @@ trait StdNames {
 
   abstract class CommonNames extends NamesApi {
     type NameType >: Null <: Name
+    // Masking some implicits so as to allow our targeted => NameType.
+    protected val stringToTermName = null
+    protected val stringToTypeName = null
     protected implicit def createNameType(name: String): NameType
 
     def flattenedName(segments: Name*): NameType =
@@ -963,7 +966,7 @@ trait StdNames {
         case -1     => if (name == "") scala.Nil else scala.List(mkName(name, assumeTerm))
         // otherwise, we can tell based on whether '#' or '.' is the following char.
         case idx    =>
-          val (simple, div, rest) = (name take idx, name charAt idx, newTermName(name) drop (idx + 1))
+          val (simple, div, rest) = (name take idx, name charAt idx, name drop idx + 1)
           mkName(simple, div == '.') :: segments(rest, assumeTerm)
       }
     }
@@ -1038,6 +1041,8 @@ trait StdNames {
   }
 
   abstract class SymbolNames {
+    protected val stringToTermName = null
+    protected val stringToTypeName = null
     protected implicit def createNameType(s: String): TypeName = newTypeNameCached(s)
 
     val BeanProperty        : TypeName