jdk8-mips64-public/langtools: src/share/classes/com/sun/tools/javac/comp/Resolve.java@e2722bd43f3a (annotated)

src/share/classes/com/sun/tools/javac/comp/Resolve.java@e2722bd43f3a (annotated)

src/share/classes/com/sun/tools/javac/comp/Resolve.java

Mon, 04 May 2009 21:04:04 -0700

author: jrose
date: Mon, 04 May 2009 21:04:04 -0700
changeset 267: e2722bd43f3a
parent 254: 1ee128971f5d
child 299: 22872b24d38c
permissions: -rw-r--r--

6829189: Java programming with JSR 292 needs language support
Summary: Language changes documented in http://wikis.sun.com/display/mlvm/ProjectCoinProposal
Reviewed-by: jjg, darcy, mcimadamore

 /*
  * Copyright 1999-2008 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Sun designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Sun in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  */
 package com.sun.tools.javac.comp;
 import com.sun.tools.javac.util.*;
 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
 import com.sun.tools.javac.code.*;
 import com.sun.tools.javac.jvm.*;
 import com.sun.tools.javac.tree.*;
 import com.sun.tools.javac.api.Formattable.LocalizedString;
 import static com.sun.tools.javac.comp.Resolve.MethodResolutionPhase.*;
 import com.sun.tools.javac.code.Type.*;
 import com.sun.tools.javac.code.Symbol.*;
 import com.sun.tools.javac.tree.JCTree.*;
 import static com.sun.tools.javac.code.Flags.*;
 import static com.sun.tools.javac.code.Kinds.*;
 import static com.sun.tools.javac.code.TypeTags.*;
 import javax.lang.model.element.ElementVisitor;
 import java.util.Map;
 import java.util.HashMap;
 /** Helper class for name resolution, used mostly by the attribution phase.
  *
  *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If
  *  you write code that depends on this, you do so at your own risk.
  *  This code and its internal interfaces are subject to change or
  *  deletion without notice.</b>
  */
 public class Resolve {
     protected static final Context.Key<Resolve> resolveKey =
         new Context.Key<Resolve>();
     Names names;
     Log log;
     Symtab syms;
     Check chk;
     Infer infer;
     ClassReader reader;
     TreeInfo treeinfo;
     Types types;
     JCDiagnostic.Factory diags;
     public final boolean boxingEnabled; // = source.allowBoxing();
     public final boolean varargsEnabled; // = source.allowVarargs();
     public final boolean allowInvokedynamic; // = options.get("invokedynamic");
     private final boolean debugResolve;
     public static Resolve instance(Context context) {
         Resolve instance = context.get(resolveKey);
         if (instance == null)
             instance = new Resolve(context);
         return instance;
     }
     protected Resolve(Context context) {
         context.put(resolveKey, this);
         syms = Symtab.instance(context);
         varNotFound = new
             ResolveError(ABSENT_VAR, syms.errSymbol, "variable not found");
         wrongMethod = new
             ResolveError(WRONG_MTH, syms.errSymbol, "method not found");
         wrongMethods = new
             ResolveError(WRONG_MTHS, syms.errSymbol, "wrong methods");
         methodNotFound = new
             ResolveError(ABSENT_MTH, syms.errSymbol, "method not found");
         typeNotFound = new
             ResolveError(ABSENT_TYP, syms.errSymbol, "type not found");
         names = Names.instance(context);
         log = Log.instance(context);
         chk = Check.instance(context);
         infer = Infer.instance(context);
         reader = ClassReader.instance(context);
         treeinfo = TreeInfo.instance(context);
         types = Types.instance(context);
         diags = JCDiagnostic.Factory.instance(context);
         Source source = Source.instance(context);
         boxingEnabled = source.allowBoxing();
         varargsEnabled = source.allowVarargs();
         Options options = Options.instance(context);
         debugResolve = options.get("debugresolve") != null;
         allowInvokedynamic = options.get("invokedynamic") != null;
     }
     /** error symbols, which are returned when resolution fails
      */
     final ResolveError varNotFound;
     final ResolveError wrongMethod;
     final ResolveError wrongMethods;
     final ResolveError methodNotFound;
     final ResolveError typeNotFound;
 /* ************************************************************************
  * Identifier resolution
  *************************************************************************/
     /** An environment is "static" if its static level is greater than
      *  the one of its outer environment
      */
     static boolean isStatic(Env<AttrContext> env) {
         return env.info.staticLevel > env.outer.info.staticLevel;
     }
     /** An environment is an "initializer" if it is a constructor or
      *  an instance initializer.
      */
     static boolean isInitializer(Env<AttrContext> env) {
         Symbol owner = env.info.scope.owner;
         return owner.isConstructor() ||
             owner.owner.kind == TYP &&
             (owner.kind == VAR ||
              owner.kind == MTH && (owner.flags() & BLOCK) != 0) &&
             (owner.flags() & STATIC) == 0;
     }
     /** Is class accessible in given evironment?
      *  @param env    The current environment.
      *  @param c      The class whose accessibility is checked.
      */
     public boolean isAccessible(Env<AttrContext> env, TypeSymbol c) {
         switch ((short)(c.flags() & AccessFlags)) {
         case PRIVATE:
             return
                 env.enclClass.sym.outermostClass() ==
                 c.owner.outermostClass();
         case 0:
             return
                 env.toplevel.packge == c.owner // fast special case
                 ||
                 env.toplevel.packge == c.packge()
                 ||
                 // Hack: this case is added since synthesized default constructors
                 // of anonymous classes should be allowed to access
                 // classes which would be inaccessible otherwise.
                 env.enclMethod != null &&
                 (env.enclMethod.mods.flags & ANONCONSTR) != 0;
         default: // error recovery
         case PUBLIC:
             return true;
         case PROTECTED:
             return
                 env.toplevel.packge == c.owner // fast special case
                 ||
                 env.toplevel.packge == c.packge()
                 ||
                 isInnerSubClass(env.enclClass.sym, c.owner);
         }
     }
     //where
         /** Is given class a subclass of given base class, or an inner class
          *  of a subclass?
          *  Return null if no such class exists.
          *  @param c     The class which is the subclass or is contained in it.
          *  @param base  The base class
          */
         private boolean isInnerSubClass(ClassSymbol c, Symbol base) {
             while (c != null && !c.isSubClass(base, types)) {
                 c = c.owner.enclClass();
             }
             return c != null;
         }
     boolean isAccessible(Env<AttrContext> env, Type t) {
         return (t.tag == ARRAY)
             ? isAccessible(env, types.elemtype(t))
             : isAccessible(env, t.tsym);
     }
     /** Is symbol accessible as a member of given type in given evironment?
      *  @param env    The current environment.
      *  @param site   The type of which the tested symbol is regarded
      *                as a member.
      *  @param sym    The symbol.
      */
     public boolean isAccessible(Env<AttrContext> env, Type site, Symbol sym) {
         if (sym.name == names.init && sym.owner != site.tsym) return false;
         ClassSymbol sub;
         switch ((short)(sym.flags() & AccessFlags)) {
         case PRIVATE:
             return
                 (env.enclClass.sym == sym.owner // fast special case
                  ||
                  env.enclClass.sym.outermostClass() ==
                  sym.owner.outermostClass())
                 &&
                 sym.isInheritedIn(site.tsym, types);
         case 0:
             return
                 (env.toplevel.packge == sym.owner.owner // fast special case
                  ||
                  env.toplevel.packge == sym.packge())
                 &&
                 isAccessible(env, site)
                 &&
                 sym.isInheritedIn(site.tsym, types)
                 &&
                 notOverriddenIn(site, sym);
         case PROTECTED:
             return
                 (env.toplevel.packge == sym.owner.owner // fast special case
                  ||
                  env.toplevel.packge == sym.packge()
                  ||
                  isProtectedAccessible(sym, env.enclClass.sym, site)
                  ||
                  // OK to select instance method or field from 'super' or type name
                  // (but type names should be disallowed elsewhere!)
                  env.info.selectSuper && (sym.flags() & STATIC) == 0 && sym.kind != TYP)
                 &&
                 isAccessible(env, site)
                 &&
                 notOverriddenIn(site, sym);
         default: // this case includes erroneous combinations as well
             return isAccessible(env, site) && notOverriddenIn(site, sym);
         }
     }
     //where
     /* `sym' is accessible only if not overridden by
      * another symbol which is a member of `site'
      * (because, if it is overridden, `sym' is not strictly
      * speaking a member of `site'.)
      */
     private boolean notOverriddenIn(Type site, Symbol sym) {
         if (sym.kind != MTH || sym.isConstructor() || sym.isStatic())
             return true;
         else {
             Symbol s2 = ((MethodSymbol)sym).implementation(site.tsym, types, true);
             return (s2 == null || s2 == sym);
         }
     }
     //where
         /** Is given protected symbol accessible if it is selected from given site
          *  and the selection takes place in given class?
          *  @param sym     The symbol with protected access
          *  @param c       The class where the access takes place
          *  @site          The type of the qualifier
          */
         private
         boolean isProtectedAccessible(Symbol sym, ClassSymbol c, Type site) {
             while (c != null &&
                    !(c.isSubClass(sym.owner, types) &&
                      (c.flags() & INTERFACE) == 0 &&
                      // In JLS 2e 6.6.2.1, the subclass restriction applies
                      // only to instance fields and methods -- types are excluded
                      // regardless of whether they are declared 'static' or not.
                      ((sym.flags() & STATIC) != 0 || sym.kind == TYP || site.tsym.isSubClass(c, types))))
                 c = c.owner.enclClass();
             return c != null;
         }
     /** Try to instantiate the type of a method so that it fits
      *  given type arguments and argument types. If succesful, return
      *  the method's instantiated type, else return null.
      *  The instantiation will take into account an additional leading
      *  formal parameter if the method is an instance method seen as a member
      *  of un underdetermined site In this case, we treat site as an additional
      *  parameter and the parameters of the class containing the method as
      *  additional type variables that get instantiated.
      *
      *  @param env         The current environment
      *  @param site        The type of which the method is a member.
      *  @param m           The method symbol.
      *  @param argtypes    The invocation's given value arguments.
      *  @param typeargtypes    The invocation's given type arguments.
      *  @param allowBoxing Allow boxing conversions of arguments.
      *  @param useVarargs Box trailing arguments into an array for varargs.
      */
     Type rawInstantiate(Env<AttrContext> env,
                         Type site,
                         Symbol m,
                         List<Type> argtypes,
                         List<Type> typeargtypes,
                         boolean allowBoxing,
                         boolean useVarargs,
                         Warner warn)
         throws Infer.NoInstanceException {
         if (useVarargs && (m.flags() & VARARGS) == 0) return null;
         Type mt = types.memberType(site, m);
         // tvars is the list of formal type variables for which type arguments
         // need to inferred.
         List<Type> tvars = env.info.tvars;
         if (typeargtypes == null) typeargtypes = List.nil();
         if (mt.tag != FORALL && typeargtypes.nonEmpty()) {
             // This is not a polymorphic method, but typeargs are supplied
             // which is fine, see JLS3 15.12.2.1
         } else if (mt.tag == FORALL && typeargtypes.nonEmpty()) {
             ForAll pmt = (ForAll) mt;
             if (typeargtypes.length() != pmt.tvars.length())
                 return null;
             // Check type arguments are within bounds
             List<Type> formals = pmt.tvars;
             List<Type> actuals = typeargtypes;
             while (formals.nonEmpty() && actuals.nonEmpty()) {
                 List<Type> bounds = types.subst(types.getBounds((TypeVar)formals.head),
                                                 pmt.tvars, typeargtypes);
                 for (; bounds.nonEmpty(); bounds = bounds.tail)
                     if (!types.isSubtypeUnchecked(actuals.head, bounds.head, warn))
                         return null;
                 formals = formals.tail;
                 actuals = actuals.tail;
             }
             mt = types.subst(pmt.qtype, pmt.tvars, typeargtypes);
         } else if (mt.tag == FORALL) {
             ForAll pmt = (ForAll) mt;
             List<Type> tvars1 = types.newInstances(pmt.tvars);
             tvars = tvars.appendList(tvars1);
             mt = types.subst(pmt.qtype, pmt.tvars, tvars1);
         }
         // find out whether we need to go the slow route via infer
         boolean instNeeded = tvars.tail != null/*inlined: tvars.nonEmpty()*/;
         for (List<Type> l = argtypes;
              l.tail != null/*inlined: l.nonEmpty()*/ && !instNeeded;
              l = l.tail) {
             if (l.head.tag == FORALL) instNeeded = true;
         }
         if (instNeeded)
             return
             infer.instantiateMethod(tvars,
                                     (MethodType)mt,
                                     argtypes,
                                     allowBoxing,
                                     useVarargs,
                                     warn);
         return
             argumentsAcceptable(argtypes, mt.getParameterTypes(),
                                 allowBoxing, useVarargs, warn)
             ? mt
             : null;
     }
     /** Same but returns null instead throwing a NoInstanceException
      */
     Type instantiate(Env<AttrContext> env,
                      Type site,
                      Symbol m,
                      List<Type> argtypes,
                      List<Type> typeargtypes,
                      boolean allowBoxing,
                      boolean useVarargs,
                      Warner warn) {
         try {
             return rawInstantiate(env, site, m, argtypes, typeargtypes,
                                   allowBoxing, useVarargs, warn);
         } catch (Infer.NoInstanceException ex) {
             return null;
         }
     }
     /** Check if a parameter list accepts a list of args.
      */
     boolean argumentsAcceptable(List<Type> argtypes,
                                 List<Type> formals,
                                 boolean allowBoxing,
                                 boolean useVarargs,
                                 Warner warn) {
         Type varargsFormal = useVarargs ? formals.last() : null;
         while (argtypes.nonEmpty() && formals.head != varargsFormal) {
             boolean works = allowBoxing
                 ? types.isConvertible(argtypes.head, formals.head, warn)
                 : types.isSubtypeUnchecked(argtypes.head, formals.head, warn);
             if (!works) return false;
             argtypes = argtypes.tail;
             formals = formals.tail;
         }
         if (formals.head != varargsFormal) return false; // not enough args
         if (!useVarargs)
             return argtypes.isEmpty();
         Type elt = types.elemtype(varargsFormal);
         while (argtypes.nonEmpty()) {
             if (!types.isConvertible(argtypes.head, elt, warn))
                 return false;
             argtypes = argtypes.tail;
         }
         return true;
     }
 /* ***************************************************************************
  *  Symbol lookup
  *  the following naming conventions for arguments are used
  *
  *       env      is the environment where the symbol was mentioned
  *       site     is the type of which the symbol is a member
  *       name     is the symbol's name
  *                if no arguments are given
  *       argtypes are the value arguments, if we search for a method
  *
  *  If no symbol was found, a ResolveError detailing the problem is returned.
  ****************************************************************************/
     /** Find field. Synthetic fields are always skipped.
      *  @param env     The current environment.
      *  @param site    The original type from where the selection takes place.
      *  @param name    The name of the field.
      *  @param c       The class to search for the field. This is always
      *                 a superclass or implemented interface of site's class.
      */
     Symbol findField(Env<AttrContext> env,
                      Type site,
                      Name name,
                      TypeSymbol c) {
         while (c.type.tag == TYPEVAR)
             c = c.type.getUpperBound().tsym;
         Symbol bestSoFar = varNotFound;
         Symbol sym;
         Scope.Entry e = c.members().lookup(name);
         while (e.scope != null) {
             if (e.sym.kind == VAR && (e.sym.flags_field & SYNTHETIC) == 0) {
                 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 || st.tag == TYPEVAR)) {
             sym = findField(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 = findField(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;
     }
     /** Resolve a field identifier, throw a fatal error if not found.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the method invocation.
      *  @param site      The type of the qualifying expression, in which
      *                   identifier is searched.
      *  @param name      The identifier's name.
      */
     public VarSymbol resolveInternalField(DiagnosticPosition pos, Env<AttrContext> env,
                                           Type site, Name name) {
         Symbol sym = findField(env, site, name, site.tsym);
         if (sym.kind == VAR) return (VarSymbol)sym;
         else throw new FatalError(
                  diags.fragment("fatal.err.cant.locate.field",
                                 name));
     }
     /** Find unqualified variable or field with given name.
      *  Synthetic fields always skipped.
      *  @param env     The current environment.
      *  @param name    The name of the variable or field.
      */
     Symbol findVar(Env<AttrContext> env, Name name) {
         Symbol bestSoFar = varNotFound;
         Symbol sym;
         Env<AttrContext> env1 = env;
         boolean staticOnly = false;
         while (env1.outer != null) {
             if (isStatic(env1)) staticOnly = true;
             Scope.Entry e = env1.info.scope.lookup(name);
             while (e.scope != null &&
                    (e.sym.kind != VAR ||
                     (e.sym.flags_field & SYNTHETIC) != 0))
                 e = e.next();
             sym = (e.scope != null)
                 ? e.sym
                 : findField(
                     env1, env1.enclClass.sym.type, name, env1.enclClass.sym);
             if (sym.exists()) {
                 if (staticOnly &&
                     sym.kind == VAR &&
                     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 = findField(env, syms.predefClass.type, name, syms.predefClass);
         if (sym.exists())
             return sym;
         if (bestSoFar.exists())
             return bestSoFar;
         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 == VAR) {
                 if (e.sym.owner.type != origin)
                     sym = sym.clone(e.getOrigin().owner);
                 return isAccessible(env, origin, sym)
                     ? sym : new AccessError(env, origin, sym);
             }
         }
         Symbol origin = null;
         e = env.toplevel.starImportScope.lookup(name);
         for (; e.scope != null; e = e.next()) {
             sym = e.sym;
             if (sym.kind != VAR)
                 continue;
             // invariant: sym.kind == VAR
             if (bestSoFar.kind < AMBIGUOUS && sym.owner != bestSoFar.owner)
                 return new AmbiguityError(bestSoFar, sym);
             else if (bestSoFar.kind >= VAR) {
                 origin = e.getOrigin().owner;
                 bestSoFar = isAccessible(env, origin.type, sym)
                     ? sym : new AccessError(env, origin.type, sym);
             }
         }
         if (bestSoFar.kind == VAR && bestSoFar.owner.type != origin.type)
             return bestSoFar.clone(origin);
         else
             return bestSoFar;
     }
     Warner noteWarner = new Warner();
     /** Select the best method for a call site among two choices.
      *  @param env              The current environment.
      *  @param site             The original type from where the
      *                          selection takes place.
      *  @param argtypes         The invocation's value arguments,
      *  @param typeargtypes     The invocation's type arguments,
      *  @param sym              Proposed new best match.
      *  @param bestSoFar        Previously found best match.
      *  @param allowBoxing Allow boxing conversions of arguments.
      *  @param useVarargs Box trailing arguments into an array for varargs.
      */
     Symbol selectBest(Env<AttrContext> env,
                       Type site,
                       List<Type> argtypes,
                       List<Type> typeargtypes,
                       Symbol sym,
                       Symbol bestSoFar,
                       boolean allowBoxing,
                       boolean useVarargs,
                       boolean operator) {
         if (sym.kind == ERR) return bestSoFar;
         if (!sym.isInheritedIn(site.tsym, types)) return bestSoFar;
         assert sym.kind < AMBIGUOUS;
         try {
             if (rawInstantiate(env, site, sym, argtypes, typeargtypes,
                                allowBoxing, useVarargs, Warner.noWarnings) == null) {
                 // inapplicable
                 switch (bestSoFar.kind) {
                 case ABSENT_MTH: return wrongMethod.setWrongSym(sym);
                 case WRONG_MTH: return wrongMethods;
                 default: return bestSoFar;
                 }
             }
         } catch (Infer.NoInstanceException ex) {
             switch (bestSoFar.kind) {
             case ABSENT_MTH:
                 return wrongMethod.setWrongSym(sym, ex.getDiagnostic());
             case WRONG_MTH:
                 return wrongMethods;
             default:
                 return bestSoFar;
             }
         }
         if (!isAccessible(env, site, sym)) {
             return (bestSoFar.kind == ABSENT_MTH)
                 ? new AccessError(env, site, sym)
                 : bestSoFar;
         }
         return (bestSoFar.kind > AMBIGUOUS)
             ? sym
             : mostSpecific(sym, bestSoFar, env, site,
                            allowBoxing && operator, useVarargs);
     }
     /* Return the most specific of the two methods for a call,
      *  given that both are accessible and applicable.
      *  @param m1               A new candidate for most specific.
      *  @param m2               The previous most specific candidate.
      *  @param env              The current environment.
      *  @param site             The original type from where the selection
      *                          takes place.
      *  @param allowBoxing Allow boxing conversions of arguments.
      *  @param useVarargs Box trailing arguments into an array for varargs.
      */
     Symbol mostSpecific(Symbol m1,
                         Symbol m2,
                         Env<AttrContext> env,
                         final Type site,
                         boolean allowBoxing,
                         boolean useVarargs) {
         switch (m2.kind) {
         case MTH:
             if (m1 == m2) return m1;
             Type mt1 = types.memberType(site, m1);
             noteWarner.unchecked = false;
             boolean m1SignatureMoreSpecific =
                 (instantiate(env, site, m2, types.lowerBoundArgtypes(mt1), null,
                              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 that both signatures have the same erasure
                 if (!types.isSameTypes(m1.erasure(types).getParameterTypes(),
                                        m2.erasure(types).getParameterTypes()))
                     return new AmbiguityError(m1, m2);
                 // both abstract, neither overridden; merge throws clause and result type
                 Symbol mostSpecific;
                 Type result2 = mt2.getReturnType();
                 if (mt2.tag == FORALL)
                     result2 = types.subst(result2, ((ForAll)mt2).tvars, ((ForAll)mt1).tvars);
                 if (types.isSubtype(mt1.getReturnType(), result2)) {
                     mostSpecific = m1;
                 } else if (types.isSubtype(result2, mt1.getReturnType())) {
                     mostSpecific = 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);
                 }
                 MethodSymbol result = new MethodSymbol(
                         mostSpecific.flags(),
                         mostSpecific.name,
                         null,
                         mostSpecific.owner) {
                     @Override
                     public MethodSymbol implementation(TypeSymbol origin, Types types, boolean checkResult) {
                         if (origin == site.tsym)
                             return this;
                         else
                             return super.implementation(origin, types, checkResult);
                     }
                 };
                 result.type = (Type)mostSpecific.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.tag == TYPEVAR; ct = types.supertype(ct)) {
             while (ct.tag == TYPEVAR)
                 ct = ct.getUpperBound();
             ClassSymbol c = (ClassSymbol)ct.tsym;
             if ((c.flags() & (ABSTRACT | INTERFACE | ENUM)) == 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;
     }
     /** Find or create an implicit method of exactly the given type (after erasure).
      *  Searches in a side table, not the main scope of the site.
      *  This emulates the lookup process required by JSR 292 in JVM.
      *  @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
      */
     Symbol findImplicitMethod(Env<AttrContext> env,
                               Type site,
                               Name name,
                               List<Type> argtypes,
                               List<Type> typeargtypes) {
         assert allowInvokedynamic;
         assert site == syms.invokeDynamicType || (site == syms.methodHandleType && name == names.invoke);
         ClassSymbol c = (ClassSymbol) site.tsym;
         Scope implicit = c.members().next;
         if (implicit == null) {
             c.members().next = implicit = new Scope(c);
         }
         Type restype;
         if (typeargtypes.isEmpty()) {
             restype = syms.objectType;
         } else {
             restype = typeargtypes.head;
             if (!typeargtypes.tail.isEmpty())
                 return methodNotFound;
         }
         List<Type> paramtypes = Type.map(argtypes, implicitArgType);
         MethodType mtype = new MethodType(paramtypes,
                                           restype,
                                           List.<Type>nil(),
                                           syms.methodClass);
         int flags = PUBLIC | ABSTRACT;
         if (site == syms.invokeDynamicType)  flags |= STATIC;
         Symbol m = null;
         for (Scope.Entry e = implicit.lookup(name);
              e.scope != null;
              e = e.next()) {
             Symbol sym = e.sym;
             assert sym.kind == MTH;
             if (types.isSameType(mtype, sym.type)
                 && (sym.flags() & STATIC) == (flags & STATIC)) {
                 m = sym;
                 break;
             }
         }
         if (m == null) {
             // create the desired method
             m = new MethodSymbol(flags, name, mtype, c);
             implicit.enter(m);
         }
         assert argumentsAcceptable(argtypes, types.memberType(site, m).getParameterTypes(),
                                    false, false, Warner.noWarnings);
         assert null != instantiate(env, site, m, argtypes, typeargtypes, false, false, Warner.noWarnings);
         return m;
     }
     //where
         Mapping implicitArgType = new Mapping ("implicitArgType") {
                 public Type apply(Type t) { return implicitArgType(t); }
             };
         Type implicitArgType(Type argType) {
             argType = types.erasure(argType);
             if (argType.tag == BOT)
                 // nulls type as the marker type Null (which has no instances)
                 // TO DO: figure out how to access java.lang.Null safely, else throw nice error
                 //argType = types.boxedClass(syms.botType).type;
                 argType = types.boxedClass(syms.voidType).type;  // REMOVE
             return argType;
         }
     /** 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) {
         Symbol bestSoFar = typeNotFound;
         for (Scope.Entry e = scope.lookup(name); e.scope != null; e = e.next()) {
             Symbol sym = loadClass(env, e.sym.flatName());
             if (bestSoFar.kind == TYP && sym.kind == TYP &&
                 bestSoFar != sym)
                 return new AmbiguityError(bestSoFar, sym);
             else if (sym.kind < bestSoFar.kind)
                 bestSoFar = sym;
         }
         return bestSoFar;
     }
     /** Find an unqualified type symbol.
      *  @param env       The current environment.
      *  @param name      The type's name.
      */
     Symbol findType(Env<AttrContext> env, Name name) {
         Symbol bestSoFar = typeNotFound;
         Symbol sym;
         boolean staticOnly = false;
         for (Env<AttrContext> env1 = env; env1.outer != null; env1 = env1.outer) {
             if (isStatic(env1)) staticOnly = true;
             for (Scope.Entry e = env1.info.scope.lookup(name);
                  e.scope != null;
                  e = e.next()) {
                 if (e.sym.kind == TYP) {
                     if (staticOnly &&
                         e.sym.type.tag == TYPEVAR &&
                         e.sym.owner.kind == TYP) return new StaticError(e.sym);
                     return e.sym;
                 }
             }
             sym = findMemberType(env1, env1.enclClass.sym.type, name,
                                  env1.enclClass.sym);
             if (staticOnly && sym.kind == TYP &&
                 sym.type.tag == CLASS &&
                 sym.type.getEnclosingType().tag == CLASS &&
                 env1.enclClass.sym.type.isParameterized() &&
                 sym.type.getEnclosingType().isParameterized())
                 return new StaticError(sym);
             else if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
             JCClassDecl encl = env1.baseClause ? (JCClassDecl)env1.tree : env1.enclClass;
             if ((encl.sym.flags() & STATIC) != 0)
                 staticOnly = true;
         }
         if (env.tree.getTag() != JCTree.IMPORT) {
             sym = findGlobalType(env, env.toplevel.namedImportScope, name);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
             sym = findGlobalType(env, env.toplevel.packge.members(), name);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
             sym = findGlobalType(env, env.toplevel.starImportScope, name);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
         }
         return bestSoFar;
     }
     /** Find an unqualified identifier which matches a specified kind set.
      *  @param env       The current environment.
      *  @param name      The indentifier's name.
      *  @param kind      Indicates the possible symbol kinds
      *                   (a subset of VAL, TYP, PCK).
      */
     Symbol findIdent(Env<AttrContext> env, Name name, int kind) {
         Symbol bestSoFar = typeNotFound;
         Symbol sym;
         if ((kind & VAR) != 0) {
             sym = findVar(env, name);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
         }
         if ((kind & TYP) != 0) {
             sym = findType(env, name);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
         }
         if ((kind & PCK) != 0) return reader.enterPackage(name);
         else return bestSoFar;
     }
     /** Find an identifier in a package which matches a specified kind set.
      *  @param env       The current environment.
      *  @param name      The identifier's name.
      *  @param kind      Indicates the possible symbol kinds
      *                   (a nonempty subset of TYP, PCK).
      */
     Symbol findIdentInPackage(Env<AttrContext> env, TypeSymbol pck,
                               Name name, int kind) {
         Name fullname = TypeSymbol.formFullName(name, pck);
         Symbol bestSoFar = typeNotFound;
         PackageSymbol pack = null;
         if ((kind & PCK) != 0) {
             pack = reader.enterPackage(fullname);
             if (pack.exists()) return pack;
         }
         if ((kind & TYP) != 0) {
             Symbol sym = loadClass(env, fullname);
             if (sym.exists()) {
                 // don't allow programs to use flatnames
                 if (name == sym.name) return sym;
             }
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
         }
         return (pack != null) ? pack : bestSoFar;
     }
     /** Find an identifier among the members of a given type `site'.
      *  @param env       The current environment.
      *  @param site      The type containing the symbol to be found.
      *  @param name      The identifier's name.
      *  @param kind      Indicates the possible symbol kinds
      *                   (a subset of VAL, TYP).
      */
     Symbol findIdentInType(Env<AttrContext> env, Type site,
                            Name name, int kind) {
         Symbol bestSoFar = typeNotFound;
         Symbol sym;
         if ((kind & VAR) != 0) {
             sym = findField(env, site, name, site.tsym);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
         }
         if ((kind & TYP) != 0) {
             sym = findMemberType(env, site, name, site.tsym);
             if (sym.exists()) return sym;
             else if (sym.kind < bestSoFar.kind) bestSoFar = sym;
         }
         return bestSoFar;
     }
 /* ***************************************************************************
  *  Access checking
  *  The following methods convert ResolveErrors to ErrorSymbols, issuing
  *  an error message in the process
  ****************************************************************************/
     /** If `sym' is a bad symbol: report error and return errSymbol
      *  else pass through unchanged,
      *  additional arguments duplicate what has been used in trying to find the
      *  symbol (--> flyweight pattern). This improves performance since we
      *  expect misses to happen frequently.
      *
      *  @param sym       The symbol that was found, or a ResolveError.
      *  @param pos       The position to use for error reporting.
      *  @param site      The original type from where the selection took place.
      *  @param name      The symbol's name.
      *  @param argtypes  The invocation's value arguments,
      *                   if we looked for a method.
      *  @param typeargtypes  The invocation's type arguments,
      *                   if we looked for a method.
      */
     Symbol access(Symbol sym,
                   DiagnosticPosition pos,
                   Type site,
                   Name name,
                   boolean qualified,
                   List<Type> argtypes,
                   List<Type> typeargtypes) {
         if (sym.kind >= AMBIGUOUS) {
 //          printscopes(site.tsym.members());//DEBUG
             if (!site.isErroneous() &&
                 !Type.isErroneous(argtypes) &&
                 (typeargtypes==null || !Type.isErroneous(typeargtypes)))
                 ((ResolveError)sym).report(log, pos, site, name, argtypes, typeargtypes);
             do {
                 sym = ((ResolveError)sym).sym;
             } while (sym.kind >= AMBIGUOUS);
             if (sym == syms.errSymbol // preserve the symbol name through errors
                 || ((sym.kind & ERRONEOUS) == 0 // make sure an error symbol is returned
                     && (sym.kind & TYP) != 0))
                 sym = types.createErrorType(name, qualified ? site.tsym : syms.noSymbol, sym.type).tsym;
         }
         return sym;
     }
     /** Same as above, but without type arguments and arguments.
      */
     Symbol access(Symbol sym,
                   DiagnosticPosition pos,
                   Type site,
                   Name name,
                   boolean qualified) {
         if (sym.kind >= AMBIGUOUS)
             return access(sym, pos, site, name, qualified, List.<Type>nil(), null);
         else
             return sym;
     }
     /** Check that sym is not an abstract method.
      */
     void checkNonAbstract(DiagnosticPosition pos, Symbol sym) {
         if ((sym.flags() & ABSTRACT) != 0)
             log.error(pos, "abstract.cant.be.accessed.directly",
                       kindName(sym), sym, sym.location());
     }
 /* ***************************************************************************
  *  Debugging
  ****************************************************************************/
     /** print all scopes starting with scope s and proceeding outwards.
      *  used for debugging.
      */
     public void printscopes(Scope s) {
         while (s != null) {
             if (s.owner != null)
                 System.err.print(s.owner + ": ");
             for (Scope.Entry e = s.elems; e != null; e = e.sibling) {
                 if ((e.sym.flags() & ABSTRACT) != 0)
                     System.err.print("abstract ");
                 System.err.print(e.sym + " ");
             }
             System.err.println();
             s = s.next;
         }
     }
     void printscopes(Env<AttrContext> env) {
         while (env.outer != null) {
             System.err.println("------------------------------");
             printscopes(env.info.scope);
             env = env.outer;
         }
     }
     public void printscopes(Type t) {
         while (t.tag == CLASS) {
             printscopes(t.tsym.members());
             t = types.supertype(t);
         }
     }
 /* ***************************************************************************
  *  Name resolution
  *  Naming conventions are as for symbol lookup
  *  Unlike the find... methods these methods will report access errors
  ****************************************************************************/
     /** Resolve an unqualified (non-method) identifier.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the identifier use.
      *  @param name      The identifier's name.
      *  @param kind      The set of admissible symbol kinds for the identifier.
      */
     Symbol resolveIdent(DiagnosticPosition pos, Env<AttrContext> env,
                         Name name, int kind) {
         return access(
             findIdent(env, name, kind),
             pos, env.enclClass.sym.type, name, false);
     }
     /** Resolve an unqualified method identifier.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the method invocation.
      *  @param name      The identifier's name.
      *  @param argtypes  The types of the invocation's value arguments.
      *  @param typeargtypes  The types of the invocation's type arguments.
      */
     Symbol resolveMethod(DiagnosticPosition pos,
                          Env<AttrContext> env,
                          Name name,
                          List<Type> argtypes,
                          List<Type> typeargtypes) {
         Symbol sym = methodNotFound;
         List<MethodResolutionPhase> steps = methodResolutionSteps;
         while (steps.nonEmpty() &&
                steps.head.isApplicable(boxingEnabled, varargsEnabled) &&
                sym.kind >= ERRONEOUS) {
             sym = findFun(env, name, argtypes, typeargtypes,
                     steps.head.isBoxingRequired,
                     env.info.varArgs = steps.head.isVarargsRequired);
             methodResolutionCache.put(steps.head, sym);
             steps = steps.tail;
         }
         if (sym.kind >= AMBIGUOUS) {//if nothing is found return the 'first' error
             MethodResolutionPhase errPhase =
                     firstErroneousResolutionPhase();
             sym = access(methodResolutionCache.get(errPhase),
                     pos, env.enclClass.sym.type, name, false, argtypes, typeargtypes);
             env.info.varArgs = errPhase.isVarargsRequired;
         }
         return sym;
     }
     /** Resolve a qualified method identifier
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the method invocation.
      *  @param site      The type of the qualifying expression, in which
      *                   identifier is searched.
      *  @param name      The identifier's name.
      *  @param argtypes  The types of the invocation's value arguments.
      *  @param typeargtypes  The types of the invocation's type arguments.
      */
     Symbol resolveQualifiedMethod(DiagnosticPosition pos, Env<AttrContext> env,
                                   Type site, Name name, List<Type> argtypes,
                                   List<Type> typeargtypes) {
         Symbol sym = methodNotFound;
         List<MethodResolutionPhase> steps = methodResolutionSteps;
         while (steps.nonEmpty() &&
                steps.head.isApplicable(boxingEnabled, varargsEnabled) &&
                sym.kind >= ERRONEOUS) {
             sym = findMethod(env, site, name, argtypes, typeargtypes,
                     steps.head.isBoxingRequired(),
                     env.info.varArgs = steps.head.isVarargsRequired(), false);
             methodResolutionCache.put(steps.head, sym);
             steps = steps.tail;
         }
         if (sym.kind >= AMBIGUOUS &&
             allowInvokedynamic &&
             (site == syms.invokeDynamicType ||
              site == syms.methodHandleType && name == names.invoke)) {
             // lookup failed; supply an exactly-typed implicit method
             sym = findImplicitMethod(env, site, name, argtypes, typeargtypes);
             env.info.varArgs = false;
         }
         if (sym.kind >= AMBIGUOUS) {//if nothing is found return the 'first' error
             MethodResolutionPhase errPhase =
                     firstErroneousResolutionPhase();
             sym = access(methodResolutionCache.get(errPhase),
                     pos, site, name, true, argtypes, typeargtypes);
             env.info.varArgs = errPhase.isVarargsRequired;
         }
         return sym;
     }
     /** Resolve a qualified method identifier, throw a fatal error if not
      *  found.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the method invocation.
      *  @param site      The type of the qualifying expression, in which
      *                   identifier is searched.
      *  @param name      The identifier's name.
      *  @param argtypes  The types of the invocation's value arguments.
      *  @param typeargtypes  The types of the invocation's type arguments.
      */
     public MethodSymbol resolveInternalMethod(DiagnosticPosition pos, Env<AttrContext> env,
                                         Type site, Name name,
                                         List<Type> argtypes,
                                         List<Type> typeargtypes) {
         Symbol sym = resolveQualifiedMethod(
             pos, env, site, name, argtypes, typeargtypes);
         if (sym.kind == MTH) return (MethodSymbol)sym;
         else throw new FatalError(
                  diags.fragment("fatal.err.cant.locate.meth",
                                 name));
     }
     /** Resolve constructor.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the constructor invocation.
      *  @param site      The type of class for which a constructor is searched.
      *  @param argtypes  The types of the constructor invocation's value
      *                   arguments.
      *  @param typeargtypes  The types of the constructor invocation's type
      *                   arguments.
      */
     Symbol resolveConstructor(DiagnosticPosition pos,
                               Env<AttrContext> env,
                               Type site,
                               List<Type> argtypes,
                               List<Type> typeargtypes) {
         Symbol sym = methodNotFound;
         List<MethodResolutionPhase> steps = methodResolutionSteps;
         while (steps.nonEmpty() &&
                steps.head.isApplicable(boxingEnabled, varargsEnabled) &&
                sym.kind >= ERRONEOUS) {
             sym = resolveConstructor(pos, env, site, argtypes, typeargtypes,
                     steps.head.isBoxingRequired(),
                     env.info.varArgs = steps.head.isVarargsRequired());
             methodResolutionCache.put(steps.head, sym);
             steps = steps.tail;
         }
         if (sym.kind >= AMBIGUOUS) {//if nothing is found return the 'first' error
             MethodResolutionPhase errPhase = firstErroneousResolutionPhase();
             sym = access(methodResolutionCache.get(errPhase),
                     pos, site, names.init, true, argtypes, typeargtypes);
             env.info.varArgs = errPhase.isVarargsRequired();
         }
         return sym;
     }
     /** Resolve constructor.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the constructor invocation.
      *  @param site      The type of class for which a constructor is searched.
      *  @param argtypes  The types of the constructor invocation's value
      *                   arguments.
      *  @param typeargtypes  The types of the constructor invocation's type
      *                   arguments.
      *  @param allowBoxing Allow boxing and varargs conversions.
      *  @param useVarargs Box trailing arguments into an array for varargs.
      */
     Symbol resolveConstructor(DiagnosticPosition pos, Env<AttrContext> env,
                               Type site, List<Type> argtypes,
                               List<Type> typeargtypes,
                               boolean allowBoxing,
                               boolean useVarargs) {
         Symbol sym = findMethod(env, site,
                                 names.init, argtypes,
                                 typeargtypes, allowBoxing,
                                 useVarargs, false);
         if ((sym.flags() & DEPRECATED) != 0 &&
             (env.info.scope.owner.flags() & DEPRECATED) == 0 &&
             env.info.scope.owner.outermostClass() != sym.outermostClass())
             chk.warnDeprecated(pos, sym);
         return sym;
     }
     /** Resolve a constructor, throw a fatal error if not found.
      *  @param pos       The position to use for error reporting.
      *  @param env       The environment current at the method invocation.
      *  @param site      The type to be constructed.
      *  @param argtypes  The types of the invocation's value arguments.
      *  @param typeargtypes  The types of the invocation's type arguments.
      */
     public MethodSymbol resolveInternalConstructor(DiagnosticPosition pos, Env<AttrContext> env,
                                         Type site,
                                         List<Type> argtypes,
                                         List<Type> typeargtypes) {
         Symbol sym = resolveConstructor(
             pos, env, site, argtypes, typeargtypes);
         if (sym.kind == MTH) return (MethodSymbol)sym;
         else throw new FatalError(
                  diags.fragment("fatal.err.cant.locate.ctor", site));
     }
     /** Resolve operator.
      *  @param pos       The position to use for error reporting.
      *  @param optag     The tag of the operation tree.
      *  @param env       The environment current at the operation.
      *  @param argtypes  The types of the operands.
      */
     Symbol resolveOperator(DiagnosticPosition pos, int optag,
                            Env<AttrContext> env, List<Type> argtypes) {
         Name name = treeinfo.operatorName(optag);
         Symbol sym = findMethod(env, syms.predefClass.type, name, argtypes,
                                 null, false, false, true);
         if (boxingEnabled && sym.kind >= WRONG_MTHS)
             sym = findMethod(env, syms.predefClass.type, name, argtypes,
                              null, true, false, true);
         return access(sym, pos, env.enclClass.sym.type, name,
                       false, argtypes, null);
     }
     /** Resolve operator.
      *  @param pos       The position to use for error reporting.
      *  @param optag     The tag of the operation tree.
      *  @param env       The environment current at the operation.
      *  @param arg       The type of the operand.
      */
     Symbol resolveUnaryOperator(DiagnosticPosition pos, int optag, Env<AttrContext> env, Type arg) {
         return resolveOperator(pos, optag, env, List.of(arg));
     }
     /** Resolve binary operator.
      *  @param pos       The position to use for error reporting.
      *  @param optag     The tag of the operation tree.
      *  @param env       The environment current at the operation.
      *  @param left      The types of the left operand.
      *  @param right     The types of the right operand.
      */
     Symbol resolveBinaryOperator(DiagnosticPosition pos,
                                  int optag,
                                  Env<AttrContext> env,
                                  Type left,
                                  Type right) {
         return resolveOperator(pos, optag, env, List.of(left, right));
     }
     /**
      * Resolve `c.name' where name == this or name == super.
      * @param pos           The position to use for error reporting.
      * @param env           The environment current at the expression.
      * @param c             The qualifier.
      * @param name          The identifier's name.
      */
     Symbol resolveSelf(DiagnosticPosition pos,
                        Env<AttrContext> env,
                        TypeSymbol c,
                        Name name) {
         Env<AttrContext> env1 = env;
         boolean staticOnly = false;
         while (env1.outer != null) {
             if (isStatic(env1)) staticOnly = true;
             if (env1.enclClass.sym == c) {
                 Symbol sym = env1.info.scope.lookup(name).sym;
                 if (sym != null) {
                     if (staticOnly) sym = new StaticError(sym);
                     return access(sym, pos, env.enclClass.sym.type,
                                   name, true);
                 }
             }
             if ((env1.enclClass.sym.flags() & STATIC) != 0) staticOnly = true;
             env1 = env1.outer;
         }
         log.error(pos, "not.encl.class", c);
         return syms.errSymbol;
     }
     /**
      * Resolve `c.this' for an enclosing class c that contains the
      * named member.
      * @param pos           The position to use for error reporting.
      * @param env           The environment current at the expression.
      * @param member        The member that must be contained in the result.
      */
     Symbol resolveSelfContaining(DiagnosticPosition pos,
                                  Env<AttrContext> env,
                                  Symbol member) {
         Name name = names._this;
         Env<AttrContext> env1 = env;
         boolean staticOnly = false;
         while (env1.outer != null) {
             if (isStatic(env1)) staticOnly = true;
             if (env1.enclClass.sym.isSubClass(member.owner, types) &&
                 isAccessible(env, env1.enclClass.sym.type, member)) {
                 Symbol sym = env1.info.scope.lookup(name).sym;
                 if (sym != null) {
                     if (staticOnly) sym = new StaticError(sym);
                     return access(sym, pos, env.enclClass.sym.type,
                                   name, true);
                 }
             }
             if ((env1.enclClass.sym.flags() & STATIC) != 0)
                 staticOnly = true;
             env1 = env1.outer;
         }
         log.error(pos, "encl.class.required", member);
         return syms.errSymbol;
     }
     /**
      * Resolve an appropriate implicit this instance for t's container.
      * JLS2 8.8.5.1 and 15.9.2
      */
     Type resolveImplicitThis(DiagnosticPosition pos, Env<AttrContext> env, Type t) {
         Type thisType = (((t.tsym.owner.kind & (MTH|VAR)) != 0)
                          ? resolveSelf(pos, env, t.getEnclosingType().tsym, names._this)
                          : resolveSelfContaining(pos, env, t.tsym)).type;
         if (env.info.isSelfCall && thisType.tsym == env.enclClass.sym)
             log.error(pos, "cant.ref.before.ctor.called", "this");
         return thisType;
     }
 /* ***************************************************************************
  *  ResolveError classes, indicating error situations when accessing symbols
  ****************************************************************************/
     public void logAccessError(Env<AttrContext> env, JCTree tree, Type type) {
         AccessError error = new AccessError(env, type.getEnclosingType(), type.tsym);
         error.report(log, tree.pos(), type.getEnclosingType(), null, null, null);
     }
     private final LocalizedString noArgs = new LocalizedString("compiler.misc.no.args");
     public Object methodArguments(List<Type> argtypes) {
         return argtypes.isEmpty() ? noArgs : argtypes;
     }
     /** Root class for resolve errors.
      *  Instances of this class indicate "Symbol not found".
      *  Instances of subclass indicate other errors.
      */
     private class ResolveError extends Symbol {
         ResolveError(int kind, Symbol sym, String debugName) {
             super(kind, 0, null, null, null);
             this.debugName = debugName;
             this.sym = sym;
         }
         /** The name of the kind of error, for debugging only.
          */
         final String debugName;
         /** The symbol that was determined by resolution, or errSymbol if none
          *  was found.
          */
         final Symbol sym;
         /** The symbol that was a close mismatch, or null if none was found.
          *  wrongSym is currently set if a simgle method with the correct name, but
          *  the wrong parameters was found.
          */
         Symbol wrongSym;
         /** An auxiliary explanation set in case of instantiation errors.
          */
         JCDiagnostic explanation;
         public <R, P> R accept(ElementVisitor<R, P> v, P p) {
             throw new AssertionError();
         }
         /** Print the (debug only) name of the kind of error.
          */
         public String toString() {
             return debugName + " wrongSym=" + wrongSym + " explanation=" + explanation;
         }
         /** Update wrongSym and explanation and return this.
          */
         ResolveError setWrongSym(Symbol sym, JCDiagnostic explanation) {
             this.wrongSym = sym;
             this.explanation = explanation;
             return this;
         }
         /** Update wrongSym and return this.
          */
         ResolveError setWrongSym(Symbol sym) {
             this.wrongSym = sym;
             this.explanation = null;
             return this;
         }
         public boolean exists() {
             switch (kind) {
             case HIDDEN:
             case ABSENT_VAR:
             case ABSENT_MTH:
             case ABSENT_TYP:
                 return false;
             default:
                 return true;
             }
         }
         /** Report error.
          *  @param log       The error log to be used for error reporting.
          *  @param pos       The position to be used for error reporting.
          *  @param site      The original type from where the selection took place.
          *  @param name      The name of the symbol to be resolved.
          *  @param argtypes  The invocation's value arguments,
          *                   if we looked for a method.
          *  @param typeargtypes  The invocation's type arguments,
          *                   if we looked for a method.
          */
         void report(Log log, DiagnosticPosition pos, Type site, Name name,
                     List<Type> argtypes, List<Type> typeargtypes) {
             if (argtypes == null)
                 argtypes = List.nil();
             if (typeargtypes == null)
                 typeargtypes = List.nil();
             if (name != names.error) {
                 KindName kindname = absentKind(kind);
                 Name idname = name;
                 if (kind >= WRONG_MTHS && kind <= ABSENT_MTH) {
                     if (isOperator(name)) {
                         log.error(pos, "operator.cant.be.applied",
                                   name, argtypes);
                         return;
                     }
                     if (name == names.init) {
                         kindname = KindName.CONSTRUCTOR;
                         idname = site.tsym.name;
                     }
                 }
                 if (kind == WRONG_MTH) {
                     Symbol ws = wrongSym.asMemberOf(site, types);
                     log.error(pos,
                               "cant.apply.symbol" + (explanation != null ? ".1" : ""),
                               kindname,
                               ws.name == names.init ? ws.owner.name : ws.name,
                               methodArguments(ws.type.getParameterTypes()),
                               methodArguments(argtypes),
                               kindName(ws.owner),
                               ws.owner.type,
                               explanation);
                 } else if (!site.tsym.name.isEmpty()) {
                     if (site.tsym.kind == PCK && !site.tsym.exists())
                         log.error(pos, "doesnt.exist", site.tsym);
                     else {
                         String errKey = getErrorKey("cant.resolve.location",
                                                     argtypes, typeargtypes,
                                                     kindname);
                         log.error(pos, errKey, kindname, idname, //symbol kindname, name
                                   typeargtypes, argtypes, //type parameters and arguments (if any)
                                   typeKindName(site), site); //location kindname, type
                     }
                 } else {
                     String errKey = getErrorKey("cant.resolve",
                                                 argtypes, typeargtypes,
                                                 kindname);
                     log.error(pos, errKey, kindname, idname, //symbol kindname, name
                               typeargtypes, argtypes); //type parameters and arguments (if any)
                 }
             }
         }
         //where
         String getErrorKey(String key, List<Type> argtypes, List<Type> typeargtypes, KindName kindname) {
             String suffix = "";
             switch (kindname) {
                 case METHOD:
                 case CONSTRUCTOR: {
                     suffix += ".args";
                     suffix += typeargtypes.nonEmpty() ? ".params" : "";
                 }
             }
             return key + suffix;
         }
         /** A name designates an operator if it consists
          *  of a non-empty sequence of operator symbols +-~!/*%&|^<>=
          */
         boolean isOperator(Name name) {
             int i = 0;
             while (i < name.getByteLength() &&
                    "+-~!*/%&|^<>=".indexOf(name.getByteAt(i)) >= 0) i++;
             return i > 0 && i == name.getByteLength();
         }
     }
     /** Resolve error class indicating that a symbol is not accessible.
      */
     class AccessError extends ResolveError {
         AccessError(Symbol sym) {
             this(null, null, sym);
         }
         AccessError(Env<AttrContext> env, Type site, Symbol sym) {
             super(HIDDEN, sym, "access error");
             this.env = env;
             this.site = site;
             if (debugResolve)
                 log.error("proc.messager", sym + " @ " + site + " is inaccessible.");
         }
         private Env<AttrContext> env;
         private Type site;
         /** Report error.
          *  @param log       The error log to be used for error reporting.
          *  @param pos       The position to be used for error reporting.
          *  @param site      The original type from where the selection took place.
          *  @param name      The name of the symbol to be resolved.
          *  @param argtypes  The invocation's value arguments,
          *                   if we looked for a method.
          *  @param typeargtypes  The invocation's type arguments,
          *                   if we looked for a method.
          */
         void report(Log log, DiagnosticPosition pos, Type site, Name name,
                     List<Type> argtypes, List<Type> typeargtypes) {
             if (sym.owner.type.tag != ERROR) {
                 if (sym.name == names.init && sym.owner != site.tsym)
                     new ResolveError(ABSENT_MTH, sym.owner, "absent method " + sym).report(
                         log, pos, site, name, argtypes, typeargtypes);
                 if ((sym.flags() & PUBLIC) != 0
                     || (env != null && this.site != null
                         && !isAccessible(env, this.site)))
                     log.error(pos, "not.def.access.class.intf.cant.access",
                         sym, sym.location());
                 else if ((sym.flags() & (PRIVATE | PROTECTED)) != 0)
                     log.error(pos, "report.access", sym,
                               asFlagSet(sym.flags() & (PRIVATE | PROTECTED)),
                               sym.location());
                 else
                     log.error(pos, "not.def.public.cant.access",
                               sym, sym.location());
             }
         }
     }
     /** Resolve error class indicating that an instance member was accessed
      *  from a static context.
      */
     class StaticError extends ResolveError {
         StaticError(Symbol sym) {
             super(STATICERR, sym, "static error");
         }
         /** Report error.
          *  @param log       The error log to be used for error reporting.
          *  @param pos       The position to be used for error reporting.
          *  @param site      The original type from where the selection took place.
          *  @param name      The name of the symbol to be resolved.
          *  @param argtypes  The invocation's value arguments,
          *                   if we looked for a method.
          *  @param typeargtypes  The invocation's type arguments,
          *                   if we looked for a method.
          */
         void report(Log log,
                     DiagnosticPosition pos,
                     Type site,
                     Name name,
                     List<Type> argtypes,
                     List<Type> typeargtypes) {
             Symbol errSym = ((sym.kind == TYP && sym.type.tag == CLASS)
                 ? types.erasure(sym.type).tsym
                 : sym);
             log.error(pos, "non-static.cant.be.ref",
                       kindName(sym), errSym);
         }
     }
     /** Resolve error class indicating an ambiguous reference.
      */
     class AmbiguityError extends ResolveError {
         Symbol sym1;
         Symbol sym2;
         AmbiguityError(Symbol sym1, Symbol sym2) {
             super(AMBIGUOUS, sym1, "ambiguity error");
             this.sym1 = sym1;
             this.sym2 = sym2;
         }
         /** Report error.
          *  @param log       The error log to be used for error reporting.
          *  @param pos       The position to be used for error reporting.
          *  @param site      The original type from where the selection took place.
          *  @param name      The name of the symbol to be resolved.
          *  @param argtypes  The invocation's value arguments,
          *                   if we looked for a method.
          *  @param typeargtypes  The invocation's type arguments,
          *                   if we looked for a method.
          */
         void report(Log log, DiagnosticPosition pos, Type site, Name name,
                     List<Type> argtypes, List<Type> typeargtypes) {
             AmbiguityError pair = this;
             while (true) {
                 if (pair.sym1.kind == AMBIGUOUS)
                     pair = (AmbiguityError)pair.sym1;
                 else if (pair.sym2.kind == AMBIGUOUS)
                     pair = (AmbiguityError)pair.sym2;
                 else break;
             }
             Name sname = pair.sym1.name;
             if (sname == names.init) sname = pair.sym1.owner.name;
             log.error(pos, "ref.ambiguous", sname,
                       kindName(pair.sym1),
                       pair.sym1,
                       pair.sym1.location(site, types),
                       kindName(pair.sym2),
                       pair.sym2,
                       pair.sym2.location(site, types));
         }
     }
     enum MethodResolutionPhase {
         BASIC(false, false),
         BOX(true, false),
         VARARITY(true, true);
         boolean isBoxingRequired;
         boolean isVarargsRequired;
         MethodResolutionPhase(boolean isBoxingRequired, boolean isVarargsRequired) {
            this.isBoxingRequired = isBoxingRequired;
            this.isVarargsRequired = isVarargsRequired;
         }
         public boolean isBoxingRequired() {
             return isBoxingRequired;
         }
         public boolean isVarargsRequired() {
             return isVarargsRequired;
         }
         public boolean isApplicable(boolean boxingEnabled, boolean varargsEnabled) {
             return (varargsEnabled || !isVarargsRequired) &&
                    (boxingEnabled || !isBoxingRequired);
         }
     }
     private Map<MethodResolutionPhase, Symbol> methodResolutionCache =
         new HashMap<MethodResolutionPhase, Symbol>(MethodResolutionPhase.values().length);
     final List<MethodResolutionPhase> methodResolutionSteps = List.of(BASIC, BOX, VARARITY);
     private MethodResolutionPhase firstErroneousResolutionPhase() {
         MethodResolutionPhase bestSoFar = BASIC;
         Symbol sym = methodNotFound;
         List<MethodResolutionPhase> steps = methodResolutionSteps;
         while (steps.nonEmpty() &&
                steps.head.isApplicable(boxingEnabled, varargsEnabled) &&
                sym.kind >= WRONG_MTHS) {
             sym = methodResolutionCache.get(steps.head);
             bestSoFar = steps.head;
             steps = steps.tail;
         }
         return bestSoFar;
     }
 }

Mercurial > jdk8-mips64-public > langtools / annotate

src/share/classes/com/sun/tools/javac/comp/Resolve.java@e2722bd43f3a (annotated)

src/share/classes/com/sun/tools/javac/comp/Resolve.java