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author | Martin Odersky <odersky@gmail.com> | 2017-01-29 17:54:30 +1100 |
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committer | Guillaume Martres <smarter@ubuntu.com> | 2017-01-29 14:44:30 +0100 |
commit | 56fb15888fb98e3a6a535f5734bb8ce82fcd76c3 (patch) | |
tree | c1e01cce8a76a5e66ba2a54472bc899ae41ca405 /compiler/src/dotty/tools/dotc/transform | |
parent | 6e8933ccc40bbfe1a92c32c2d8314fd6facef12a (diff) | |
download | dotty-56fb15888fb98e3a6a535f5734bb8ce82fcd76c3.tar.gz dotty-56fb15888fb98e3a6a535f5734bb8ce82fcd76c3.tar.bz2 dotty-56fb15888fb98e3a6a535f5734bb8ce82fcd76c3.zip |
Fix #1750: Handle illegal class overrides better
Illegal class overrides are fundamentally at odds with the way dotty
represents types and therefore can cause lots of low-level problems.
Two measures in this commit
First, we detect direct illegal class overrides on completion instead of
during RefChecks. Break the override by making the previously
overriding type private.
This fixes i1750.scala, but still fails for indirect overrides between
two unrelated outer traits/classes that are inherited by the same class or trait.
We fix this by catching the previously thrown ClassCastException
in both ExtractAPI and RefChecks.
Test case for indirect overrides is in i1750a.scala.
Diffstat (limited to 'compiler/src/dotty/tools/dotc/transform')
-rw-r--r-- | compiler/src/dotty/tools/dotc/transform/OverridingPairs.scala | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/compiler/src/dotty/tools/dotc/transform/OverridingPairs.scala b/compiler/src/dotty/tools/dotc/transform/OverridingPairs.scala index 650a03054..1f1f371a6 100644 --- a/compiler/src/dotty/tools/dotc/transform/OverridingPairs.scala +++ b/compiler/src/dotty/tools/dotc/transform/OverridingPairs.scala @@ -6,6 +6,7 @@ import Flags._, Symbols._, Contexts._, Types._, Scopes._, Decorators._ import util.HashSet import collection.mutable import collection.immutable.BitSet +import typer.ErrorReporting.cyclicErrorMsg import scala.annotation.tailrec /** A module that can produce a kind of iterator (`Cursor`), @@ -122,10 +123,18 @@ object OverridingPairs { if (nextEntry ne null) { nextEntry = decls.lookupNextEntry(nextEntry) if (nextEntry ne null) { - overridden = nextEntry.sym - if (overriding.owner != overridden.owner && matches(overriding, overridden)) { - visited += overridden - if (!hasCommonParentAsSubclass(overriding.owner, overridden.owner)) return + try { + overridden = nextEntry.sym + if (overriding.owner != overridden.owner && matches(overriding, overridden)) { + visited += overridden + if (!hasCommonParentAsSubclass(overriding.owner, overridden.owner)) return + } + } + catch { + case ex: CyclicReference => + // See neg/i1750a for an example where a cyclic error can arise. + // The root cause in this example is an illegal "override" of an inner trait + ctx.error(cyclicErrorMsg(ex), base.pos) } } else { curEntry = curEntry.prev |