From 06690117f3b67d947df5ef14cd02a55341b94d1c Mon Sep 17 00:00:00 2001 From: Martin Odersky Date: Thu, 18 Jun 2015 10:31:48 +0200 Subject: Fix stack overflow when testing for shadowing Shadowing tests could go into an infinite recursion when the found sahdwoing member itself needs an implicit that is resolved and then shadowed again by the same member. A test case is neg/arrayclone-new.scala. This caused a SO before, now gives two errors. --- src/dotty/tools/dotc/typer/Implicits.scala | 5 +++-- src/dotty/tools/dotc/typer/Mode.scala | 5 +++++ 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/dotty/tools/dotc/typer/Implicits.scala b/src/dotty/tools/dotc/typer/Implicits.scala index b03bcfcf9..841390ef1 100644 --- a/src/dotty/tools/dotc/typer/Implicits.scala +++ b/src/dotty/tools/dotc/typer/Implicits.scala @@ -491,7 +491,7 @@ trait Implicits { self: Typer => pt) val generated1 = adapt(generated, pt) lazy val shadowing = - typed(untpd.Ident(ref.name) withPos pos.toSynthetic, funProto)(nestedContext.setNewTyperState) + typed(untpd.Ident(ref.name) withPos pos.toSynthetic, funProto)(nestedContext.setNewTyperState.addMode(Mode.ImplicitShadowing)) def refMatches(shadowing: Tree): Boolean = ref.symbol == closureBody(shadowing).symbol || { shadowing match { @@ -501,7 +501,8 @@ trait Implicits { self: Typer => } if (ctx.typerState.reporter.hasErrors) nonMatchingImplicit(ref) - else if (contextual && !shadowing.tpe.isError && !refMatches(shadowing)) { + else if (contextual && !ctx.mode.is(Mode.ImplicitShadowing) && + !shadowing.tpe.isError && !refMatches(shadowing)) { implicits.println(i"SHADOWING $ref in ${ref.termSymbol.owner} is shadowed by $shadowing in ${shadowing.symbol.owner}") shadowedImplicit(ref, methPart(shadowing).tpe) } diff --git a/src/dotty/tools/dotc/typer/Mode.scala b/src/dotty/tools/dotc/typer/Mode.scala index 8889cf604..e84ef2784 100644 --- a/src/dotty/tools/dotc/typer/Mode.scala +++ b/src/dotty/tools/dotc/typer/Mode.scala @@ -68,5 +68,10 @@ object Mode { */ val Printing = newMode(10, "Printing") + /** We are currently typechecking an ident to determine whether some implicit + * is shadowed - don't do any other shadowing tests. + */ + val ImplicitShadowing = newMode(11, "ImplicitShadowing") + val PatternOrType = Pattern | Type } -- cgit v1.2.3