From 411d5be477cc862b14d8938c591524d8bf37d4cd Mon Sep 17 00:00:00 2001
From: Guillaume Martres <smarter@ubuntu.com>
Date: Sat, 4 Apr 2015 01:15:16 +0200
Subject: New phase: VCInline which inlines value classes calls

This corresponds roughly to step 2 of SIP-15 and to the peephole
optimizations of step 3.

The extractors in TreeExtractors are copied or inspired from
src/compiler/scala/tools/nsc/ast/TreeInfo.scala in scalac.
---
 .../tools/dotc/transform/TreeExtractors.scala      | 48 ++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 src/dotty/tools/dotc/transform/TreeExtractors.scala

(limited to 'src/dotty/tools/dotc/transform/TreeExtractors.scala')

diff --git a/src/dotty/tools/dotc/transform/TreeExtractors.scala b/src/dotty/tools/dotc/transform/TreeExtractors.scala
new file mode 100644
index 000000000..7a5c5df9d
--- /dev/null
+++ b/src/dotty/tools/dotc/transform/TreeExtractors.scala
@@ -0,0 +1,48 @@
+package dotty.tools.dotc
+package transform
+
+import ast.{Trees, tpd}
+import core._, core.Decorators._
+import Contexts._, Flags._, Trees._, Types._, StdNames._, Symbols._
+import ValueClasses._
+
+object TreeExtractors {
+  import tpd._
+
+  /** Match arg1.op(arg2) and extract (arg1, op.symbol, arg2) */
+  object BinaryOp {
+    def unapply(t: Tree)(implicit ctx: Context): Option[(Tree, Symbol, Tree)] = t match {
+      case Apply(sel @ Select(arg1, _), List(arg2)) =>
+        Some((arg1, sel.symbol, arg2))
+      case _ =>
+        None
+    }
+  }
+
+ /** Match new C(args) and extract (C, args) */
+  object NewWithArgs {
+    def unapply(t: Tree)(implicit ctx: Context): Option[(Type, List[Tree])] = t match {
+      case Apply(Select(New(_), nme.CONSTRUCTOR), args) =>
+        Some((t.tpe, args))
+      case _ =>
+        None
+    }
+  }
+
+  /** For an instance v of a value class like:
+   *    class V(val underlying: X) extends AnyVal
+   *  Match v.underlying() and extract v
+   */
+  object ValueClassUnbox {
+    def unapply(t: Tree)(implicit ctx: Context): Option[Tree] = t match {
+      case Apply(sel @ Select(ref, _), Nil) =>
+        val d = ref.tpe.widenDealias.typeSymbol.denot
+        if (isDerivedValueClass(d) && (sel.symbol eq valueClassUnbox(d.asClass))) {
+          Some(ref)
+        } else
+          None
+      case _ =>
+        None
+    }
+  }
+}
-- 
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