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author | Guillaume Martres <smarter@ubuntu.com> | 2015-11-25 00:07:13 +0100 |
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committer | Guillaume Martres <smarter@ubuntu.com> | 2015-11-25 02:11:17 +0100 |
commit | 81b7ed9abb9627d541b795990980f4431b459380 (patch) | |
tree | 86b9976cdcaee86082e9d8c35ed24fe59d9c2cc3 /src/dotty/tools/dotc | |
parent | 4463f5e705480c7da188695abdb0ccacf452103c (diff) | |
download | dotty-81b7ed9abb9627d541b795990980f4431b459380.tar.gz dotty-81b7ed9abb9627d541b795990980f4431b459380.tar.bz2 dotty-81b7ed9abb9627d541b795990980f4431b459380.zip |
isSubtype: try to dealias TypeRefs before recursively checking the prefixes
As demonstrated by tests/pos/hk-deep-subtype.scala, we can avoid some
deep subtype recursions that result in stack overflows by doing this.
Fix #943.
Diffstat (limited to 'src/dotty/tools/dotc')
-rw-r--r-- | src/dotty/tools/dotc/core/TypeComparer.scala | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/dotty/tools/dotc/core/TypeComparer.scala b/src/dotty/tools/dotc/core/TypeComparer.scala index 6e2346710..0d46a4b90 100644 --- a/src/dotty/tools/dotc/core/TypeComparer.scala +++ b/src/dotty/tools/dotc/core/TypeComparer.scala @@ -144,8 +144,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling { case info2: TypeAlias => isSubType(tp1, info2.alias) case _ => info1 match { case info1: TypeAlias => isSubType(info1.alias, tp2) - case NoType => secondTry(tp1, tp2) - case _ => thirdTryNamed(tp1, tp2) + case _ => false } } def compareNamed = { @@ -153,6 +152,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling { tp1 match { case tp1: NamedType => val sym1 = tp1.symbol + compareAlias(tp1.info) || (if ((sym1 ne NoSymbol) && (sym1 eq tp2.symbol)) ctx.erasedTypes || sym1.isStaticOwner || isSubType(tp1.prefix, tp2.prefix) else @@ -164,10 +164,11 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling { ) || compareHK(tp1, tp2, inOrder = true) || compareHK(tp2, tp1, inOrder = false) || - compareAlias(tp1.info) + thirdTryNamed(tp1, tp2) case _ => compareHK(tp2, tp1, inOrder = false) || - compareAlias(NoType) + compareAlias(NoType) || + secondTry(tp1, tp2) } } compareNamed |