From 56fb15888fb98e3a6a535f5734bb8ce82fcd76c3 Mon Sep 17 00:00:00 2001 From: Martin Odersky Date: Sun, 29 Jan 2017 17:54:30 +1100 Subject: 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. --- compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'compiler/src/dotty/tools/dotc/sbt') diff --git a/compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala b/compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala index 1fffe6841..7f44af486 100644 --- a/compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala +++ b/compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala @@ -6,6 +6,7 @@ import core._, core.Decorators._ import Annotations._, Contexts._, Flags._, Phases._, Trees._, Types._, Symbols._ import Names._, NameOps._, StdNames._ import typer.Inliner +import typer.ErrorReporting.cyclicErrorMsg import dotty.tools.io.Path import java.io.PrintWriter @@ -190,7 +191,16 @@ private class ExtractAPICollector(implicit val ctx: Context) extends ThunkHolder def apiClassStructure(csym: ClassSymbol): api.Structure = { val cinfo = csym.classInfo - val bases = linearizedAncestorTypes(cinfo) + val bases = + try linearizedAncestorTypes(cinfo) + 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), csym.pos) + defn.ObjectType :: Nil + } + val apiBases = bases.map(apiType) // Synthetic methods that are always present do not affect the API -- cgit v1.2.3