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| author | Martin Odersky <odersky@gmail.com> | 2016-10-13 16:51:05 +0200 |
|---|---|---|
| committer | Martin Odersky <odersky@gmail.com> | 2016-10-13 16:51:18 +0200 |
| commit | a45a3e5f573fc5b768fcd0d6be507a0af8fd53cc (patch) | |
| tree | 4ca6be161907fa2d19d1289c5ee0956c02302a81 | |
| parent | dac5b931bcf8757070c8aa74571e52f3b4c6e5eb (diff) | |
| download | dotty-a45a3e5f573fc5b768fcd0d6be507a0af8fd53cc.tar.gz dotty-a45a3e5f573fc5b768fcd0d6be507a0af8fd53cc.tar.bz2 dotty-a45a3e5f573fc5b768fcd0d6be507a0af8fd53cc.zip | |
Fix #1590: Eliminate wildcards when approximating a type
Fixes #1590. Type variables should never be instantiated to types
containing wildcards.
| -rw-r--r-- | src/dotty/tools/dotc/core/ConstraintHandling.scala | 6 | ||||
| -rw-r--r-- | tests/pos/i1590.scala | 1 |
2 files changed, 6 insertions, 1 deletions
diff --git a/src/dotty/tools/dotc/core/ConstraintHandling.scala b/src/dotty/tools/dotc/core/ConstraintHandling.scala index 3835d553c..95fa40704 100644 --- a/src/dotty/tools/dotc/core/ConstraintHandling.scala +++ b/src/dotty/tools/dotc/core/ConstraintHandling.scala @@ -162,7 +162,8 @@ trait ConstraintHandling { /** Solve constraint set for given type parameter `param`. * If `fromBelow` is true the parameter is approximated by its lower bound, * otherwise it is approximated by its upper bound. However, any occurrences - * of the parameter in a refinement somewhere in the bound are removed. + * of the parameter in a refinement somewhere in the bound are removed. Also + * wildcard types in bounds are approximated by their upper or lower bounds. * (Such occurrences can arise for F-bounded types). * The constraint is left unchanged. * @return the instantiating type @@ -174,6 +175,9 @@ trait ConstraintHandling { def apply(tp: Type) = mapOver { tp match { case tp: RefinedType if param occursIn tp.refinedInfo => tp.parent + case tp: WildcardType => + val bounds = tp.optBounds.orElse(TypeBounds.empty).bounds + if (fromBelow == (variance >= 0)) bounds.lo else bounds.hi case _ => tp } } diff --git a/tests/pos/i1590.scala b/tests/pos/i1590.scala new file mode 100644 index 000000000..a8f36de45 --- /dev/null +++ b/tests/pos/i1590.scala @@ -0,0 +1 @@ +case class W[T](seq: Option[Option[T]] = Option.empty) |