From 69d4d8c0a34c94e72d69af1039c0a6131b97bb82 Mon Sep 17 00:00:00 2001 From: Adriaan Moors Date: Fri, 21 Aug 2009 08:57:51 +0000 Subject: improved previous fix for implicits and `conforms` because conforms/identity was no longer prevented from being used as a view (which does not make sense, but preventing it shouldn't be necessary), removeNames in NamesDefaults suddenly didn't detect all ambiguities because it relied on tryTypedApply failing fixed by using an EmptyTree as an ambiguous argument instead of the argument, so failure is guaranteed fixed check file for t0590 also reintroduced conforms, because we now have a new starr --- src/compiler/scala/tools/nsc/typechecker/Implicits.scala | 4 +++- src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala | 9 ++++++++- src/compiler/scala/tools/nsc/typechecker/Typers.scala | 6 ++++-- 3 files changed, 15 insertions(+), 4 deletions(-) (limited to 'src/compiler') diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala index c23d29f159..0472f4fb21 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala @@ -420,7 +420,9 @@ self: Analyzer => */ def tryImplicit(info: ImplicitInfo): SearchResult = if (containsError(info.tpe) || - (isLocal && shadowed.contains(info.name)) // || (isView && (info.sym == Predef_identity || info.sym == Predef_conforms)) + (isLocal && shadowed.contains(info.name)) //|| + // (isView && (info.sym == Predef_identity || info.sym == Predef_conforms})) //@M this condition prevents no-op conversions, which are a problem (besides efficiency), + // one example is removeNames in NamesDefaults, which relies on the type checker failing in case of ambiguity between an assignment/named arg ) SearchFailure else typedImplicit(info) diff --git a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala index 482c53fac5..9d485cc730 100644 --- a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala +++ b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala @@ -390,9 +390,16 @@ trait NamesDefaults { self: Analyzer => argPos(index) = pos rhs case t: Tree => - errorTree(arg, "reference to "+ name +" is ambiguous; it is both, a parameter\n"+ + //@M was: errorTree(arg, ...) + // this throws an exception that's caught in `tryTypedApply` (as it uses `silent`) + // unfortunately, tryTypedApply recovers from the exception if you use errorTree(arg, ...) and conforms is allowed as a view (see tryImplicit in Implicits) + // because it tries to produce a new qualifier (if the old one was P, the new one will be conforms.apply(P)), and if that works, it pretends nothing happened + // so, to make sure tryTypedApply fails, pass EmptyTree instead + errorTree(EmptyTree, "reference to "+ name +" is ambiguous; it is both, a parameter\n"+ "name of the method and the name of a variable currently in scope.") } + //@M note that we don't get here when an ambiguity was detected (during the computation of res), + // as errorTree throws an exception typer.context.undetparams = udp res } diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 13a9d6e142..b609f1f24b 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -992,8 +992,10 @@ trait Typers { self: Analyzer => ((qual.symbol eq null) || !qual.symbol.isTerm || qual.symbol.isValue) && phase.id <= currentRun.typerPhase.id && !qtpe.isError && !tp.isError && qtpe.typeSymbol != NullClass && qtpe.typeSymbol != NothingClass && qtpe != WildcardType && - context.implicitsEnabled) { // don't try to convert a top-level type that's the subject of an implicit search - // (otherwise we get divergence, e.g., starting at `conforms` during ant quick.bin) + context.implicitsEnabled) { // don't try to adapt a top-level type that's the subject of an implicit search + // this happens because, if isView, typedImplicit tries to apply the "current" implicit value to + // a value that needs to be coerced, so we check whether the implicit value has an `apply` method + // (if we allow this, we get divergence, e.g., starting at `conforms` during ant quick.bin) // note: implicit arguments are still inferred (this kind of "chaining" is allowed) val coercion = inferView(qual, qtpe, name, tp) if (coercion != EmptyTree) -- cgit v1.2.3