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| author | Guillaume Martres <smarter@ubuntu.com> | 2016-10-14 19:45:29 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2016-10-14 19:45:29 +0200 |
| commit | c5aa4ec052cae047486cffe7495d0bc02c103357 (patch) | |
| tree | e8cb8173b939cef2870296c8d35bec12212b7102 /src | |
| parent | bac4eecd27d113294a6531bbc272c96dfae86f57 (diff) | |
| parent | a4594ddc496cb4599188ce047cf783aa92465288 (diff) | |
| download | dotty-c5aa4ec052cae047486cffe7495d0bc02c103357.tar.gz dotty-c5aa4ec052cae047486cffe7495d0bc02c103357.tar.bz2 dotty-c5aa4ec052cae047486cffe7495d0bc02c103357.zip | |
Merge pull request #1598 from dotty-staging/fix-#1515
Fix #1515: Don't narrow gadt bounds when frozen
Diffstat (limited to 'src')
| -rw-r--r-- | src/dotty/tools/dotc/core/TypeComparer.scala | 43 |
1 files changed, 22 insertions, 21 deletions
diff --git a/src/dotty/tools/dotc/core/TypeComparer.scala b/src/dotty/tools/dotc/core/TypeComparer.scala index b495f00d0..1980fe50d 100644 --- a/src/dotty/tools/dotc/core/TypeComparer.scala +++ b/src/dotty/tools/dotc/core/TypeComparer.scala @@ -965,28 +965,29 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling { * Test that the resulting bounds are still satisfiable. */ private def narrowGADTBounds(tr: NamedType, bound: Type, isUpper: Boolean): Boolean = - ctx.mode.is(Mode.GADTflexible) && { - val tparam = tr.symbol - typr.println(i"narrow gadt bound of $tparam: ${tparam.info} from ${if (isUpper) "above" else "below"} to $bound ${bound.isRef(tparam)}") - if (bound.isRef(tparam)) false - else bound match { - case bound: TypeRef - if bound.symbol.is(BindDefinedType) && ctx.gadt.bounds.contains(bound.symbol) && - !tr.symbol.is(BindDefinedType) => - // Avoid having pattern-bound types in gadt bounds, - // as these might be eliminated once the pattern is typechecked. - // Pattern-bound type symbols should be narrowed first, only if that fails - // should symbols in the environment be constrained. - narrowGADTBounds(bound, tr, !isUpper) - case _ => - val oldBounds = ctx.gadt.bounds(tparam) - val newBounds = - if (isUpper) TypeBounds(oldBounds.lo, oldBounds.hi & bound) - else TypeBounds(oldBounds.lo | bound, oldBounds.hi) - isSubType(newBounds.lo, newBounds.hi) && - { ctx.gadt.setBounds(tparam, newBounds); true } + ctx.mode.is(Mode.GADTflexible) && !frozenConstraint && { + val tparam = tr.symbol + typr.println(i"narrow gadt bound of $tparam: ${tparam.info} from ${if (isUpper) "above" else "below"} to $bound ${bound.isRef(tparam)}") + if (bound.isRef(tparam)) false + else bound match { + case bound: TypeRef + if bound.symbol.is(BindDefinedType) && + ctx.gadt.bounds.contains(bound.symbol) && + !tr.symbol.is(BindDefinedType) => + // Avoid having pattern-bound types in gadt bounds, + // as these might be eliminated once the pattern is typechecked. + // Pattern-bound type symbols should be narrowed first, only if that fails + // should symbols in the environment be constrained. + narrowGADTBounds(bound, tr, !isUpper) + case _ => + val oldBounds = ctx.gadt.bounds(tparam) + val newBounds = + if (isUpper) TypeBounds(oldBounds.lo, oldBounds.hi & bound) + else TypeBounds(oldBounds.lo | bound, oldBounds.hi) + isSubType(newBounds.lo, newBounds.hi) && + { ctx.gadt.setBounds(tparam, newBounds); true } + } } - } // Tests around `matches` |