resolve.java

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                             allowBoxing, false, noteWarner) != null ||
                 useVarargs && instantiate(env, site, m2, types.lowerBoundArgtypes(mt1), null,
                                           allowBoxing, true, noteWarner) != null) &&
                !noteWarner.unchecked;
            Type mt2 = types.memberType(site, m2);
            noteWarner.unchecked = false;
            boolean m2SignatureMoreSpecific =
                (instantiate(env, site, m1, types.lowerBoundArgtypes(mt2), null,
                             allowBoxing, false, noteWarner) != null ||
                 useVarargs && instantiate(env, site, m1, types.lowerBoundArgtypes(mt2), null,
                                           allowBoxing, true, noteWarner) != null) &&
                !noteWarner.unchecked;
            if (m1SignatureMoreSpecific && m2SignatureMoreSpecific) {
                if (!types.overrideEquivalent(mt1, mt2))
                    return new AmbiguityError(m1, m2);
                // same signature; select (a) the non-bridge method, or
                // (b) the one that overrides the other, or (c) the concrete
                // one, or (d) merge both abstract signatures
                if ((m1.flags() & BRIDGE) != (m2.flags() & BRIDGE)) {
                    return ((m1.flags() & BRIDGE) != 0) ? m2 : m1;
                }
                // if one overrides or hides the other, use it
                TypeSymbol m1Owner = (TypeSymbol)m1.owner;
                TypeSymbol m2Owner = (TypeSymbol)m2.owner;
                if (types.asSuper(m1Owner.type, m2Owner) != null &&
                    ((m1.owner.flags_field & INTERFACE) == 0 ||
                     (m2.owner.flags_field & INTERFACE) != 0) &&
                    m1.overrides(m2, m1Owner, types, false))
                    return m1;
                if (types.asSuper(m2Owner.type, m1Owner) != null &&
                    ((m2.owner.flags_field & INTERFACE) == 0 ||
                     (m1.owner.flags_field & INTERFACE) != 0) &&
                    m2.overrides(m1, m2Owner, types, false))
                    return m2;
                boolean m1Abstract = (m1.flags() & ABSTRACT) != 0;
                boolean m2Abstract = (m2.flags() & ABSTRACT) != 0;
                if (m1Abstract && !m2Abstract) return m2;
                if (m2Abstract && !m1Abstract) return m1;
                // both abstract or both concrete
                if (!m1Abstract && !m2Abstract)
                    return new AmbiguityError(m1, m2);
                // check for same erasure
                if (!types.isSameType(m1.erasure(types), m2.erasure(types)))
                    return new AmbiguityError(m1, m2);
                // both abstract, neither overridden; merge throws clause and result type
                Symbol result;
                Type result2 = mt2.getReturnType();;
                if (mt2.tag == FORALL)
                    result2 = types.subst(result2, ((ForAll)mt2).tvars, ((ForAll)mt1).tvars);
                if (types.isSubtype(mt1.getReturnType(), result2)) {
                    result = m1;
                } else if (types.isSubtype(result2, mt1.getReturnType())) {
                    result = m2;
                } else {
                    // Theoretically, this can't happen, but it is possible
                    // due to error recovery or mixing incompatible class files
                    return new AmbiguityError(m1, m2);
                }
                result = result.clone(result.owner);
                result.type = (Type)result.type.clone();
                result.type.setThrown(chk.intersect(mt1.getThrownTypes(),
                                                    mt2.getThrownTypes()));
                return result;
            }
            if (m1SignatureMoreSpecific) return m1;
            if (m2SignatureMoreSpecific) return m2;
            return new AmbiguityError(m1, m2);
        case AMBIGUOUS:
            AmbiguityError e = (AmbiguityError)m2;
            Symbol err1 = mostSpecific(m1, e.sym1, env, site, allowBoxing, useVarargs);
            Symbol err2 = mostSpecific(m1, e.sym2, env, site, allowBoxing, useVarargs);
            if (err1 == err2) return err1;
            if (err1 == e.sym1 && err2 == e.sym2) return m2;
            if (err1 instanceof AmbiguityError &&
                err2 instanceof AmbiguityError &&
                ((AmbiguityError)err1).sym1 == ((AmbiguityError)err2).sym1)
                return new AmbiguityError(m1, m2);
            else
                return new AmbiguityError(err1, err2);
        default:
            throw new AssertionError();
        }
    }

    /** Find best qualified method matching given name, type and value
     *  arguments.
     *  @param env       The current environment.
     *  @param site      The original type from where the selection
     *                   takes place.
     *  @param name      The method's name.
     *  @param argtypes  The method's value arguments.
     *  @param typeargtypes The method's type arguments
     *  @param allowBoxing Allow boxing conversions of arguments.
     *  @param useVarargs Box trailing arguments into an array for varargs.
     */
    Symbol findMethod(Env<AttrContext> env,
                      Type site,
                      Name name,
                      List<Type> argtypes,
                      List<Type> typeargtypes,
                      boolean allowBoxing,
                      boolean useVarargs,
                      boolean operator) {
        return findMethod(env,
                          site,
                          name,
                          argtypes,
                          typeargtypes,
                          site.tsym.type,
                          true,
                          methodNotFound,
                          allowBoxing,
                          useVarargs,
                          operator);
    }
    // where
    private Symbol findMethod(Env<AttrContext> env,
                              Type site,
                              Name name,
                              List<Type> argtypes,
                              List<Type> typeargtypes,
                              Type intype,
                              boolean abstractok,
                              Symbol bestSoFar,
                              boolean allowBoxing,
                              boolean useVarargs,
                              boolean operator) {
        for (Type ct = intype; ct.tag == CLASS; ct = types.supertype(ct)) {
            ClassSymbol c = (ClassSymbol)ct.tsym;
            if ((c.flags() & (ABSTRACT | INTERFACE)) == 0)
                abstractok = false;
            for (Scope.Entry e = c.members().lookup(name);
                 e.scope != null;
                 e = e.next()) {
                //- System.out.println(" e " + e.sym);
                if (e.sym.kind == MTH &&
                    (e.sym.flags_field & SYNTHETIC) == 0) {
                    bestSoFar = selectBest(env, site, argtypes, typeargtypes,
                                           e.sym, bestSoFar,
                                           allowBoxing,
                                           useVarargs,
                                           operator);
                }
            }
            //- System.out.println(" - " + bestSoFar);
            if (abstractok) {
                Symbol concrete = methodNotFound;
                if ((bestSoFar.flags() & ABSTRACT) == 0)
                    concrete = bestSoFar;
                for (List<Type> l = types.interfaces(c.type);
                     l.nonEmpty();
                     l = l.tail) {
                    bestSoFar = findMethod(env, site, name, argtypes,
                                           typeargtypes,
                                           l.head, abstractok, bestSoFar,
                                           allowBoxing, useVarargs, operator);
                }
                if (concrete != bestSoFar &&
                    concrete.kind < ERR  && bestSoFar.kind < ERR &&
                    types.isSubSignature(concrete.type, bestSoFar.type))
                    bestSoFar = concrete;
            }
        }
        return bestSoFar;
    }

    /** Find unqualified method matching given name, type and value arguments.
     *  @param env       The current environment.
     *  @param name      The method's name.
     *  @param argtypes  The method's value arguments.
     *  @param typeargtypes  The method's type arguments.
     *  @param allowBoxing Allow boxing conversions of arguments.
     *  @param useVarargs Box trailing arguments into an array for varargs.
     */
    Symbol findFun(Env<AttrContext> env, Name name,
                   List<Type> argtypes, List<Type> typeargtypes,
                   boolean allowBoxing, boolean useVarargs) {
        Symbol bestSoFar = methodNotFound;
        Symbol sym;
        Env<AttrContext> env1 = env;
        boolean staticOnly = false;
        while (env1.outer != null) {
            if (isStatic(env1)) staticOnly = true;
            sym = findMethod(
                env1, env1.enclClass.sym.type, name, argtypes, typeargtypes,
                allowBoxing, useVarargs, false);
            if (sym.exists()) {
                if (staticOnly &&
                    sym.kind == MTH &&
                    sym.owner.kind == TYP &&
                    (sym.flags() & STATIC) == 0) return new StaticError(sym);
                else return sym;
            } else if (sym.kind < bestSoFar.kind) {
                bestSoFar = sym;
            }
            if ((env1.enclClass.sym.flags() & STATIC) != 0) staticOnly = true;
            env1 = env1.outer;
        }

        sym = findMethod(env, syms.predefClass.type, name, argtypes,
                         typeargtypes, allowBoxing, useVarargs, false);
        if (sym.exists())
            return sym;

        Scope.Entry e = env.toplevel.namedImportScope.lookup(name);
        for (; e.scope != null; e = e.next()) {
            sym = e.sym;
            Type origin = e.getOrigin().owner.type;
            if (sym.kind == MTH) {
                if (e.sym.owner.type != origin)
                    sym = sym.clone(e.getOrigin().owner);
                if (!isAccessible(env, origin, sym))
                    sym = new AccessError(env, origin, sym);
                bestSoFar = selectBest(env, origin,
                                       argtypes, typeargtypes,
                                       sym, bestSoFar,
                                       allowBoxing, useVarargs, false);
            }
        }
        if (bestSoFar.exists())
            return bestSoFar;

        e = env.toplevel.starImportScope.lookup(name);
        for (; e.scope != null; e = e.next()) {
            sym = e.sym;
            Type origin = e.getOrigin().owner.type;
            if (sym.kind == MTH) {
                if (e.sym.owner.type != origin)
                    sym = sym.clone(e.getOrigin().owner);
                if (!isAccessible(env, origin, sym))
                    sym = new AccessError(env, origin, sym);
                bestSoFar = selectBest(env, origin,
                                       argtypes, typeargtypes,
                                       sym, bestSoFar,
                                       allowBoxing, useVarargs, false);
            }
        }
        return bestSoFar;
    }

    /** Load toplevel or member class with given fully qualified name and
     *  verify that it is accessible.
     *  @param env       The current environment.
     *  @param name      The fully qualified name of the class to be loaded.
     */
    Symbol loadClass(Env<AttrContext> env, Name name) {
        try {
            ClassSymbol c = reader.loadClass(name);
            return isAccessible(env, c) ? c : new AccessError(c);
        } catch (ClassReader.BadClassFile err) {
            throw err;
        } catch (CompletionFailure ex) {
            return typeNotFound;
        }
    }

    /** Find qualified member type.
     *  @param env       The current environment.
     *  @param site      The original type from where the selection takes
     *                   place.
     *  @param name      The type's name.
     *  @param c         The class to search for the member type. This is
     *                   always a superclass or implemented interface of
     *                   site's class.
     */
    Symbol findMemberType(Env<AttrContext> env,
                          Type site,
                          Name name,
                          TypeSymbol c) {
        Symbol bestSoFar = typeNotFound;
        Symbol sym;
        Scope.Entry e = c.members().lookup(name);
        while (e.scope != null) {
            if (e.sym.kind == TYP) {
                return isAccessible(env, site, e.sym)
                    ? e.sym
                    : new AccessError(env, site, e.sym);
            }
            e = e.next();
        }
        Type st = types.supertype(c.type);
        if (st != null && st.tag == CLASS) {
            sym = findMemberType(env, site, name, st.tsym);
            if (sym.kind < bestSoFar.kind) bestSoFar = sym;
        }
        for (List<Type> l = types.interfaces(c.type);
             bestSoFar.kind != AMBIGUOUS && l.nonEmpty();
             l = l.tail) {
            sym = findMemberType(env, site, name, l.head.tsym);
            if (bestSoFar.kind < AMBIGUOUS && sym.kind < AMBIGUOUS &&
                sym.owner != bestSoFar.owner)
                bestSoFar = new AmbiguityError(bestSoFar, sym);
            else if (sym.kind < bestSoFar.kind)
                bestSoFar = sym;
        }
        return bestSoFar;
    }

    /** Find a global type in given scope and load corresponding class.
     *  @param env       The current environment.
     *  @param scope     The scope in which to look for the type.
     *  @param name      The type's name.
     */
    Symbol findGlobalType(Env<AttrContext> env, Scope scope, Name name) {