Drop TraitConstructors phase

It did not do enough to carry its own weight, in particular because DenotationTransformers do have
a price - every encountered denotation in the whole program is passed through them. The name change
from <init> to $init$ was all it did, that is now rolled into Mixin.

Also renamed IMPLCLASS_CONSTRUCTOR to TRAIT_CONSTRUCTOR.

5 files changed, 10 insertions, 7 deletions

diff --git a/src/dotty/tools/dotc/core/Flags.scala b/src/dotty/tools/dotc/core/Flags.scala
index 759dff0d4..f39f2bac6 100644
--- a/src/dotty/tools/dotc/core/Flags.scala
+++ b/src/dotty/tools/dotc/core/Flags.scala
@@ -388,7 +388,7 @@ object Flags {
   /** Symbol is a self name */
   final val SelfName = termFlag(54, "<selfname>")
 
-  /** Symbol is an implementation class */
+  /** Symbol is an implementation class of a Scala2 trait */
   final val ImplClass = typeFlag(54, "<implclass>")
 
   final val SelfNameOrImplClass = SelfName.toCommonFlags
diff --git a/src/dotty/tools/dotc/core/NameOps.scala b/src/dotty/tools/dotc/core/NameOps.scala
index dc94f6db1..4d6cca61d 100644
--- a/src/dotty/tools/dotc/core/NameOps.scala
+++ b/src/dotty/tools/dotc/core/NameOps.scala
@@ -62,7 +62,7 @@ object NameOps {
     def likeTyped(n: Name): N =
       (if (name.isTermName) n.toTermName else n.toTypeName).asInstanceOf[N]
 
-    def isConstructorName = name == CONSTRUCTOR || name == IMPLCLASS_CONSTRUCTOR
+    def isConstructorName = name == CONSTRUCTOR || name == TRAIT_CONSTRUCTOR
     def isExceptionResultName = name startsWith EXCEPTION_RESULT_PREFIX
     def isImplClassName = name endsWith IMPL_CLASS_SUFFIX
     def isLocalDummyName = name startsWith LOCALDUMMY_PREFIX
diff --git a/src/dotty/tools/dotc/core/StdNames.scala b/src/dotty/tools/dotc/core/StdNames.scala
index eaf4ce1e2..eb1a73625 100644
--- a/src/dotty/tools/dotc/core/StdNames.scala
+++ b/src/dotty/tools/dotc/core/StdNames.scala
@@ -232,7 +232,6 @@ object StdNames {
     val EVT2U: N                    = "evt2u$"
     val EQEQ_LOCAL_VAR: N           = "eqEqTemp$"
     val FAKE_LOCAL_THIS: N          = "this$"
-    val IMPLCLASS_CONSTRUCTOR: N    = "$init$"
     val LAZY_LOCAL: N               = "$lzy"
     val LAZY_LOCAL_INIT: N          = "$lzyINIT"
     val LAZY_FIELD_OFFSET: N        = "OFFSET$"
@@ -261,6 +260,7 @@ object StdNames {
     val SKOLEM: N                   = "<skolem>"
     val SPECIALIZED_INSTANCE: N     = "specInstance$"
     val THIS: N                     = "_$this"
+    val TRAIT_CONSTRUCTOR: N        = "$init$"
     val U2EVT: N                    = "u2evt$"
 
     final val Nil: N                = "Nil"
diff --git a/src/dotty/tools/dotc/core/SymDenotations.scala b/src/dotty/tools/dotc/core/SymDenotations.scala
index d8dddb082..78b187970 100644
--- a/src/dotty/tools/dotc/core/SymDenotations.scala
+++ b/src/dotty/tools/dotc/core/SymDenotations.scala
@@ -530,7 +530,7 @@ object SymDenotations {
     final def isClassConstructor = name == nme.CONSTRUCTOR
 
     /** Is this the constructor of a trait? */
-    final def isImplClassConstructor = name == nme.IMPLCLASS_CONSTRUCTOR
+    final def isImplClassConstructor = name == nme.TRAIT_CONSTRUCTOR
 
     /** Is this the constructor of a trait or a class */
     final def isConstructor = name.isConstructorName
@@ -1630,8 +1630,11 @@ object SymDenotations {
     override def fullName(implicit ctx: Context): Name = super.fullName
 
     override def primaryConstructor(implicit ctx: Context): Symbol = {
-      val cname = if (this is ImplClass) nme.IMPLCLASS_CONSTRUCTOR else nme.CONSTRUCTOR
-      info.decls.denotsNamed(cname).last.symbol // denotsNamed returns Symbols in reverse order of occurrence
+      def constrNamed(cname: TermName) = info.decls.denotsNamed(cname).last.symbol
+        // denotsNamed returns Symbols in reverse order of occurrence
+      if (this.is(ImplClass)) constrNamed(nme.TRAIT_CONSTRUCTOR)
+      else
+        constrNamed(nme.CONSTRUCTOR).orElse(constrNamed(nme.TRAIT_CONSTRUCTOR))
     }
 
     /** The parameter accessors of this class. Term and type accessors,
diff --git a/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala b/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala
index 9498cf43c..53e8478fa 100644
--- a/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala
+++ b/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala
@@ -438,7 +438,7 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
     }
 
     val name1 = name0.adjustIfModuleClass(flags)
-    val name = if (name1 == nme.IMPLCLASS_CONSTRUCTOR) nme.CONSTRUCTOR else name1
+    val name = if (name1 == nme.TRAIT_CONSTRUCTOR) nme.CONSTRUCTOR else name1
 
     def isClassRoot = (name == classRoot.name) && (owner == classRoot.owner) && !(flags is ModuleClass)
     def isModuleClassRoot = (name == moduleClassRoot.name) && (owner == moduleClassRoot.owner) && (flags is Module)