Use a fast path when looking up trait setter getters.

scala · Apr 7, 2020 · 8fcb94e · 8fcb94e
1 parent 0d9e3fc
commit 8fcb94e
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Showing 2 changed files with 16 additions and 12 deletions.
diff --git a/compiler/src/dotty/tools/dotc/core/NameOps.scala b/compiler/src/dotty/tools/dotc/core/NameOps.scala
@@ -259,13 +259,9 @@ object NameOps {
     def setterName: TermName = name.exclude(FieldName) ++ str.SETTER_SUFFIX
 
     def getterName: TermName =
-      if name.is(TraitSetterName) then
-        val TraitSetterName(_, original) = name
-        original.getterName
-      else
-        name.exclude(FieldName).mapLast(n =>
-          if (n.endsWith(str.SETTER_SUFFIX)) n.take(n.length - str.SETTER_SUFFIX.length).asSimpleName
-          else n)
+      name.exclude(FieldName).mapLast(n =>
+        if (n.endsWith(str.SETTER_SUFFIX)) n.take(n.length - str.SETTER_SUFFIX.length).asSimpleName
+        else n)
 
     def fieldName: TermName =
       if (name.isSetterName)

diff --git a/compiler/src/dotty/tools/dotc/transform/Memoize.scala b/compiler/src/dotty/tools/dotc/transform/Memoize.scala
@@ -117,12 +117,20 @@ class Memoize extends MiniPhase with IdentityDenotTransformer { thisPhase =>
 
     def traitSetterGetter: Symbol =
       /* We have to compare SimpleNames here, because the setter name only
-       * embed the original getter's simple name, not its semantic name.
+       * embeds the original getter's simple name, not its semantic name.
+       * To mitigate the issue, we first try a fast path where we look up the
+       * simple name itself, which works for public fields.
        */
-      val getterSimpleName = sym.asTerm.name.getterName
-      sym.owner.info.decls.find { getter =>
-        getter.is(Accessor) && getter.asTerm.name.toSimpleName == getterSimpleName
-      }
+      val TraitSetterName(_, original) = sym.name
+      val getterSimpleName = original.getterName
+      val ownerInfo = sym.owner.info
+      val fastPath = ownerInfo.decl(getterSimpleName)
+      if fastPath.exists then
+        fastPath.symbol
+      else
+        ownerInfo.decls.find { getter =>
+          getter.is(Accessor) && getter.asTerm.name.toSimpleName == getterSimpleName
+        }
 
     if (sym.is(Accessor, butNot = NoFieldNeeded)
         && (!sym.name.is(TraitSetterName) || traitSetterGetter.is(Accessor, butNot = NoFieldNeeded))) {