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SI-8046 Only use fast TypeRef#baseTypeSeq with concrete base types

We can only compute the base type sequence (BTS) of a `TypeRef` by
element-wise transforming the BTS of the referenced symbol if
there are no abstract types in its BTS type symbols.

In the now-working test case, `pos/t8046.scala`, the difference
between the old and new calculation of the BTS is:

    this                 = Three.this.Alias[Int]
    sym.info.baseTypeSeq = BTS(One.this.Op[A],Any)
    mapped BTS           = BTS(Three.this.Op[Int],Any)
    full BTS             = BTS(Three.this.Op[Int],Int => Int,Object,Any)

The change to account for PolyType in ArgsTypeRef#transform is now
needed to avoid the full BTS of:

    BTS(Three.this.Op[A],A => A,Object,Any)

Interestingly, everything actually works without that change.
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1 parent 0de991f commit 6f42bd6881f9b1a6fa25d744cded38f53058538c @retronym retronym committed Dec 8, 2013
@@ -1999,7 +1999,9 @@ trait Types
if (sym.typeParams.size != args.size)
devWarning(s"$this.transform($tp), but tparams.isEmpty and args=$args")
- asSeenFromOwner(tp).instantiateTypeParams(sym.typeParams, args)
+ val GenPolyType(tparams, result) = asSeenFromOwner(tp)
+ assert((tparams eq Nil) || tparams == sym.typeParams, (tparams, sym.typeParams))
+ result.instantiateTypeParams(sym.typeParams, args)
}
// note: does not go through typeRef. There's no need to because
@@ -2309,7 +2311,14 @@ trait Types
}
thisInfo.decls
}
- protected[Types] def baseTypeSeqImpl: BaseTypeSeq = sym.info.baseTypeSeq map transform
+ protected[Types] def baseTypeSeqImpl: BaseTypeSeq =
+ if (sym.info.baseTypeSeq exists (_.typeSymbolDirect.isAbstractType))
+ // SI-8046 base type sequence might have more elements in a subclass, we can't map it element wise.
+ transform(sym.info).baseTypeSeq
+ else
+ // Optimization: no abstract types, we can compute the BTS of this TypeRef as an element-wise map
+ // of the BTS of the referenced symbol.
+ sym.info.baseTypeSeq map transform
override def baseTypeSeq: BaseTypeSeq = {
val cache = baseTypeSeqCache
@@ -5,7 +5,7 @@ trait One {
trait Three extends One {
trait Op[A] extends (A => A)
-
+
def f1(f: Op[Int]) = f(5)
def f2(f: Alias[Int]) = f(5)
def f3[T <: Op[Int]](f: T) = f(5)
@@ -0,0 +1,2 @@
+List(trait Op, trait Function1, class Object, class Any)
+BTS(T,Three.this.Op[Int],Int => Int,Object,Any)
@@ -0,0 +1,18 @@
+import scala.tools.partest._
+
+object Test extends DirectTest {
+ override def code = ""
+ override def extraSettings: String = "-usejavacp"
+
+ override def show() {
+ val c = newCompiler()
+ new c.Run
+ import c._
+
+ val f4 = typeOf[Three].member(newTermName("f4"))
+ val f4ParamInfo = f4.paramss.head.head.info
+ println(f4ParamInfo.baseClasses)
+ println(f4ParamInfo.baseTypeSeq)
+ }
+}
+
@@ -0,0 +1,13 @@
+import language._
+
+trait One {
+ type Op[A]
+ type Alias[A] = Op[A]
+}
+
+trait Three extends One {
+ trait Op[A] extends (A => A)
+
+ def f4[T <: Alias[Int]](f: T) = 0
+}
+

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