From bb427a34165b0338be8b23baeb61ac0591b3c0a1 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Tue, 10 Dec 2013 01:32:30 +0100 Subject: SI-8060 Avoid infinite loop with higher kinded type alias The `dealiasLocals` map was assuming that: tp.isAliasType implies (tp.dealias ne tp) This isn't true if `!typeParamsMatchArgs`. This commit avoids the infinite loop by checking whether or not dealiasing progresses. --- src/compiler/scala/tools/nsc/typechecker/Typers.scala | 2 +- test/files/pos/t8060.scala | 11 +++++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) create mode 100644 test/files/pos/t8060.scala diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index b80dcefef8..40313bdb5d 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -3826,7 +3826,7 @@ trait Typers extends Modes with Adaptations with Tags { val normalizeLocals = new TypeMap { def apply(tp: Type): Type = tp match { case TypeRef(pre, sym, args) => - if (sym.isAliasType && containsLocal(tp)) apply(tp.dealias) + if (sym.isAliasType && containsLocal(tp) && (tp.dealias ne tp)) apply(tp.dealias) else { if (pre.isVolatile) InferTypeWithVolatileTypeSelectionError(tree, pre) diff --git a/test/files/pos/t8060.scala b/test/files/pos/t8060.scala new file mode 100644 index 0000000000..90e014d74b --- /dev/null +++ b/test/files/pos/t8060.scala @@ -0,0 +1,11 @@ +trait M[F[_]] + +trait P[A] { + type CC[X] = P[X] + def f(p: A => Boolean): M[CC] +} + +trait Other { + // was infinite loop trying to dealias `x$1.CC` + def g[A](p: A => Boolean): P[A] => M[P] = _ f p +} -- cgit v1.2.3