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Merge pull request #1624 from adriaanm/paulp-issue/5330-2.10.x

SI-5330, SI-6014 deal with existential self-type
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2 parents 73d9ae5 + 65778d7 commit 2d62ab248d07f10fd89a68b12565259ca861e1e9 @adriaanm adriaanm committed Nov 16, 2012
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18 src/reflect/scala/reflect/internal/Types.scala
@@ -325,6 +325,18 @@ trait Types extends api.Types { self: SymbolTable =>
}
}
+ /** Same as a call to narrow unless existentials are visible
+ * after widening the type. In that case, narrow from the widened
+ * type instead of the proxy. This gives buried existentials a
+ * chance to make peace with the other types. See SI-5330.
+ */
+ private def narrowForFindMember(tp: Type): Type = {
+ val w = tp.widen
+ // Only narrow on widened type when we have to -- narrow is expensive unless the target is a singleton type.
+ if ((tp ne w) && containsExistential(w)) w.narrow
+ else tp.narrow
+ }
+
/** The base class for all types */
abstract class Type extends TypeApiImpl with Annotatable[Type] {
/** Types for which asSeenFrom always is the identity, no matter what
@@ -1079,7 +1091,7 @@ trait Types extends api.Types { self: SymbolTable =>
(other ne sym) &&
((other.owner eq sym.owner) ||
(flags & PRIVATE) != 0 || {
- if (self eq null) self = this.narrow
+ if (self eq null) self = narrowForFindMember(this)
if (symtpe eq null) symtpe = self.memberType(sym)
!(self.memberType(other) matches symtpe)
})}) {
@@ -1161,7 +1173,7 @@ trait Types extends api.Types { self: SymbolTable =>
if ((member ne sym) &&
((member.owner eq sym.owner) ||
(flags & PRIVATE) != 0 || {
- if (self eq null) self = this.narrow
+ if (self eq null) self = narrowForFindMember(this)
if (membertpe eq null) membertpe = self.memberType(member)
!(membertpe matches self.memberType(sym))
})) {
@@ -1176,7 +1188,7 @@ trait Types extends api.Types { self: SymbolTable =>
(other ne sym) &&
((other.owner eq sym.owner) ||
(flags & PRIVATE) != 0 || {
- if (self eq null) self = this.narrow
+ if (self eq null) self = narrowForFindMember(this)
if (symtpe eq null) symtpe = self.memberType(sym)
!(self.memberType(other) matches symtpe)
})}) {
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22 test/files/pos/t5330.scala
@@ -0,0 +1,22 @@
+trait FM[A] {
+ def map(f: A => Any)
+}
+
+trait M[A] extends FM[A] {
+ def map(f: A => Any)
+}
+
+trait N[A] extends FM[A]
+
+object test {
+ def kaboom(xs: M[_]) = xs map (x => ()) // missing parameter type.
+
+ def okay1[A](xs: M[A]) = xs map (x => ())
+ def okay2(xs: FM[_]) = xs map (x => ())
+ def okay3(xs: N[_]) = xs map (x => ())
+}
+
+class CC2(xs: List[_]) {
+ def f(x1: Any, x2: Any) = null
+ def g = xs map (x => f(x, x))
+}
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6 test/files/pos/t5330b.scala
@@ -0,0 +1,6 @@
+abstract trait Base {
+ def foo: this.type
+};
+class Derived[T] extends Base {
+ def foo: Nothing = sys.error("!!!")
+}
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5 test/files/pos/t5330c.scala
@@ -0,0 +1,5 @@
+object t5330c {
+ val s: Set[_ >: Char] = Set('A')
+ s forall ("ABC" contains _)
+ s.forall( c => "ABC".toSeq.contains( c ))
+}
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13 test/files/pos/t6014.scala
@@ -0,0 +1,13 @@
+object Test {
+ case class CC[T](key: T)
+ type Alias[T] = Seq[CC[T]]
+
+ def f(xs: Seq[CC[_]]) = xs map { case CC(x) => CC(x) } // ok
+ def g(xs: Alias[_]) = xs map { case CC(x) => CC(x) } // fails
+ // ./a.scala:11: error: missing parameter type for expanded function
+ // The argument types of an anonymous function must be fully known. (SLS 8.5)
+ // Expected type was: ?
+ // def g(xs: Alias[_]) = xs map { case CC(x) => CC(x) } // fails
+ // ^
+ // one error found
+}

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