diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Namers.scala | 19 | ||||
| -rw-r--r-- | test/files/neg/bug1275.check | 4 | ||||
| -rw-r--r-- | test/files/neg/bug1275.scala | 14 |
3 files changed, 36 insertions, 1 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala index 2e5ab49907..e82252c2ee 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala @@ -671,7 +671,24 @@ trait Namers { self: Analyzer => TypeBounds(AllClass.tpe, AnyClass.tpe) case tp => tp } - parameterizedType(tparamSyms, tp) //@M + + def verifyOverriding(other: Symbol): Boolean = { + if(other.unsafeTypeParams.length != tparamSyms.length) { + context.error(tpsym.pos, + "The kind of "+tpsym.keyString+" "+tpsym.varianceString + tpsym.nameString+ + " does not conform to the expected kind of " + other.defString + other.locationString + ".") + false + } else true + } + + // @M: make sure overriding in refinements respects rudimentary kinding + // have to do this early, as otherwise we might get crashes: (see neg/bug1275.scala) + // suppose some parameterized type member is overridden by a type member w/o params, + // then appliedType will be called on a type that does not expect type args --> crash + if (tpsym.owner.isRefinementClass && // only needed in refinements + !tpsym.allOverriddenSymbols.forall{verifyOverriding(_)}) + ErrorType + else parameterizedType(tparamSyms, tp) } def typeSig(tree: Tree): Type = { diff --git a/test/files/neg/bug1275.check b/test/files/neg/bug1275.check new file mode 100644 index 0000000000..6ff92a7823 --- /dev/null +++ b/test/files/neg/bug1275.check @@ -0,0 +1,4 @@ +bug1275.scala:13: error: The kind of type MyType does not conform to the expected kind of type MyType[+t] <: TestCovariance.this.Seq[t] in trait Seq. + def span[a, s <: Seq[a] { type MyType <: s } ](xs: s): s = xs f + ^ +one error found diff --git a/test/files/neg/bug1275.scala b/test/files/neg/bug1275.scala new file mode 100644 index 0000000000..04c66400c8 --- /dev/null +++ b/test/files/neg/bug1275.scala @@ -0,0 +1,14 @@ +// tested using Scala compiler version 2.6.0-RC1 -- (c) 2002-2007 LAMP/EPFL + +// prompted by "Covariant return types" mailing list question +object TestCovariance { + + // see Type constructor polymorphism in http://www.scala-lang.org/docu/changelog.html + trait Seq[+t] { + type MyType[+t] <: Seq[t] + + def f: MyType[t] + } + + def span[a, s <: Seq[a] { type MyType <: s } ](xs: s): s = xs f +} |