diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala | 140 |
1 files changed, 119 insertions, 21 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala b/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala index 9376cb5237..81ea5630d0 100644 --- a/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala +++ b/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala @@ -8,7 +8,6 @@ package typechecker import scala.collection.mutable import scala.collection.mutable.ListBuffer -import scala.util.control.ControlThrowable import scala.util.control.Exception.ultimately import symtab.Flags._ import PartialFunction._ @@ -37,15 +36,6 @@ trait TypeDiagnostics { import global._ import definitions._ - import global.typer.{ infer, context } - - /** The common situation of making sure nothing is erroneous could be - * nicer if Symbols, Types, and Trees all implemented some common interface - * in which isErroneous and similar would be placed. - */ - def noErroneousTypes(tps: Type*) = tps forall (x => !x.isErroneous) - def noErroneousSyms(syms: Symbol*) = syms forall (x => !x.isErroneous) - def noErroneousTrees(trees: Tree*) = trees forall (x => !x.isErroneous) /** For errors which are artifacts of the implementation: such messages * indicate that the restriction may be lifted in the future. @@ -58,7 +48,7 @@ trait TypeDiagnostics { /** A map of Positions to addendums - if an error involves a position in * the map, the addendum should also be printed. */ - private var addendums = perRunCaches.newMap[Position, () => String]() + private val addendums = perRunCaches.newMap[Position, () => String]() private var isTyperInPattern = false /** Devising new ways of communicating error info out of @@ -174,11 +164,6 @@ trait TypeDiagnostics { case xs => " where " + (disambiguate(xs map (_.existentialToString)) mkString ", ") } - def varianceWord(sym: Symbol): String = - if (sym.variance == 1) "covariant" - else if (sym.variance == -1) "contravariant" - else "invariant" - def explainAlias(tp: Type) = { // Don't automatically normalize standard aliases; they still will be // expanded if necessary to disambiguate simple identifiers. @@ -223,12 +208,12 @@ trait TypeDiagnostics { // force measures than comparing normalized Strings were producing error messages // like "and java.util.ArrayList[String] <: java.util.ArrayList[String]" but there // should be a cleaner way to do this. - if (found.normalize.toString == tp.normalize.toString) "" + if (found.dealiasWiden.toString == tp.dealiasWiden.toString) "" else " (and %s <: %s)".format(found, tp) ) val explainDef = { val prepend = if (isJava) "Java-defined " else "" - "%s%s is %s in %s.".format(prepend, reqsym, varianceWord(param), param) + "%s%s is %s in %s.".format(prepend, reqsym, param.variance, param) } // Don't suggest they change the class declaration if it's somewhere // under scala.* or defined in a java class, because attempting either @@ -248,7 +233,7 @@ trait TypeDiagnostics { || ((arg <:< reqArg) && param.isCovariant) || ((reqArg <:< arg) && param.isContravariant) ) - val invariant = param.variance == 0 + val invariant = param.variance.isInvariant if (conforms) Some("") else if ((arg <:< reqArg) && invariant) mkMsg(true) // covariant relationship @@ -291,7 +276,6 @@ trait TypeDiagnostics { // distinguished from the other types in the same error message private val savedName = sym.name def restoreName() = sym.name = savedName - def isAltered = sym.name != savedName def modifyName(f: String => String) = sym setName newTypeName(f(sym.name.toString)) /** Prepend java.lang, scala., or Predef. if this type originated @@ -421,6 +405,120 @@ trait TypeDiagnostics { def permanentlyHiddenWarning(pos: Position, hidden: Name, defn: Symbol) = contextWarning(pos, "imported `%s' is permanently hidden by definition of %s".format(hidden, defn.fullLocationString)) + object checkUnused { + val ignoreNames = Set[TermName]("readResolve", "readObject", "writeObject", "writeReplace") + + class UnusedPrivates extends Traverser { + val defnTrees = ListBuffer[MemberDef]() + val targets = mutable.Set[Symbol]() + val setVars = mutable.Set[Symbol]() + val treeTypes = mutable.Set[Type]() + + def defnSymbols = defnTrees.toList map (_.symbol) + def localVars = defnSymbols filter (t => t.isLocal && t.isVar) + + def qualifiesTerm(sym: Symbol) = ( + (sym.isModule || sym.isMethod || sym.isPrivateLocal || sym.isLocal) + && !nme.isLocalName(sym.name) + && !sym.isParameter + && !sym.isParamAccessor // could improve this, but it's a pain + && !sym.isEarlyInitialized // lots of false positives in the way these are encoded + && !(sym.isGetter && sym.accessed.isEarlyInitialized) + ) + def qualifiesType(sym: Symbol) = !sym.isDefinedInPackage + def qualifies(sym: Symbol) = ( + (sym ne null) + && (sym.isTerm && qualifiesTerm(sym) || sym.isType && qualifiesType(sym)) + ) + + override def traverse(t: Tree): Unit = { + t match { + case t: MemberDef if qualifies(t.symbol) => defnTrees += t + case t: RefTree if t.symbol ne null => targets += t.symbol + case Assign(lhs, _) if lhs.symbol != null => setVars += lhs.symbol + case _ => + } + // Only record type references which don't originate within the + // definition of the class being referenced. + if (t.tpe ne null) { + for (tp <- t.tpe ; if !treeTypes(tp) && !currentOwner.ownerChain.contains(tp.typeSymbol)) { + tp match { + case NoType | NoPrefix => + case NullaryMethodType(_) => + case MethodType(_, _) => + case _ => + log(s"$tp referenced from $currentOwner") + treeTypes += tp + } + } + // e.g. val a = new Foo ; new a.Bar ; don't let a be reported as unused. + t.tpe.prefix foreach { + case SingleType(_, sym) => targets += sym + case _ => + } + } + super.traverse(t) + } + def isUnusedType(m: Symbol): Boolean = ( + m.isType + && !m.isTypeParameterOrSkolem // would be nice to improve this + && (m.isPrivate || m.isLocal) + && !(treeTypes.exists(tp => tp exists (t => t.typeSymbolDirect == m))) + ) + def isUnusedTerm(m: Symbol): Boolean = ( + (m.isTerm) + && (m.isPrivate || m.isLocal) + && !targets(m) + && !(m.name == nme.WILDCARD) // e.g. val _ = foo + && !ignoreNames(m.name.toTermName) // serialization methods + && !isConstantType(m.info.resultType) // subject to constant inlining + && !treeTypes.exists(_ contains m) // e.g. val a = new Foo ; new a.Bar + ) + def unusedTypes = defnTrees.toList filter (t => isUnusedType(t.symbol)) + def unusedTerms = defnTrees.toList filter (v => isUnusedTerm(v.symbol)) + // local vars which are never set, except those already returned in unused + def unsetVars = localVars filter (v => !setVars(v) && !isUnusedTerm(v)) + } + + def apply(unit: CompilationUnit) = { + val p = new UnusedPrivates + p traverse unit.body + val unused = p.unusedTerms + unused foreach { defn: DefTree => + val sym = defn.symbol + val isDefaultGetter = sym.name containsName nme.DEFAULT_GETTER_STRING + val pos = ( + if (defn.pos.isDefined) defn.pos + else if (sym.pos.isDefined) sym.pos + else sym match { + case sym: TermSymbol => sym.referenced.pos + case _ => NoPosition + } + ) + val why = if (sym.isPrivate) "private" else "local" + val what = ( + if (isDefaultGetter) "default argument" + else if (sym.isConstructor) "constructor" + else if (sym.isVar || sym.isGetter && sym.accessed.isVar) "var" + else if (sym.isVal || sym.isGetter && sym.accessed.isVal) "val" + else if (sym.isSetter) "setter" + else if (sym.isMethod) "method" + else if (sym.isModule) "object" + else "term" + ) + unit.warning(pos, s"$why $what in ${sym.owner} is never used") + } + p.unsetVars foreach { v => + unit.warning(v.pos, s"local var ${v.name} in ${v.owner} is never set - it could be a val") + } + p.unusedTypes foreach { t => + val sym = t.symbol + val why = if (sym.isPrivate) "private" else "local" + unit.warning(t.pos, s"$why ${sym.fullLocationString} is never used") + } + } + } + object checkDead { private val exprStack: mutable.Stack[Symbol] = mutable.Stack(NoSymbol) // The method being applied to `tree` when `apply` is called. @@ -451,7 +549,7 @@ trait TypeDiagnostics { } // The checkDead call from typedArg is more selective. - def inMode(mode: Int, tree: Tree): Tree = { + def inMode(mode: Mode, tree: Tree): Tree = { val modeOK = (mode & (EXPRmode | BYVALmode | POLYmode)) == (EXPRmode | BYVALmode) if (modeOK) apply(tree) else tree |