Tue, 28 Dec 2010 15:54:52 -0800
6962318: Update copyright year
Reviewed-by: xdono
duke@1 | 1 | /* |
ohair@798 | 2 | * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. |
duke@1 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@1 | 4 | * |
duke@1 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@1 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ohair@554 | 7 | * published by the Free Software Foundation. Oracle designates this |
duke@1 | 8 | * particular file as subject to the "Classpath" exception as provided |
ohair@554 | 9 | * by Oracle in the LICENSE file that accompanied this code. |
duke@1 | 10 | * |
duke@1 | 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@1 | 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@1 | 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@1 | 14 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@1 | 15 | * accompanied this code). |
duke@1 | 16 | * |
duke@1 | 17 | * You should have received a copy of the GNU General Public License version |
duke@1 | 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@1 | 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@1 | 20 | * |
ohair@554 | 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
ohair@554 | 22 | * or visit www.oracle.com if you need additional information or have any |
ohair@554 | 23 | * questions. |
duke@1 | 24 | */ |
duke@1 | 25 | |
duke@1 | 26 | package com.sun.tools.javac.comp; |
duke@1 | 27 | |
mcimadamore@674 | 28 | import com.sun.tools.javac.tree.JCTree; |
mcimadamore@674 | 29 | import com.sun.tools.javac.tree.JCTree.JCTypeCast; |
duke@1 | 30 | import com.sun.tools.javac.util.*; |
duke@1 | 31 | import com.sun.tools.javac.util.List; |
duke@1 | 32 | import com.sun.tools.javac.code.*; |
duke@1 | 33 | import com.sun.tools.javac.code.Type.*; |
mcimadamore@396 | 34 | import com.sun.tools.javac.code.Type.ForAll.ConstraintKind; |
mcimadamore@299 | 35 | import com.sun.tools.javac.code.Symbol.*; |
mcimadamore@89 | 36 | import com.sun.tools.javac.util.JCDiagnostic; |
duke@1 | 37 | |
duke@1 | 38 | import static com.sun.tools.javac.code.TypeTags.*; |
duke@1 | 39 | |
duke@1 | 40 | /** Helper class for type parameter inference, used by the attribution phase. |
duke@1 | 41 | * |
jjg@581 | 42 | * <p><b>This is NOT part of any supported API. |
jjg@581 | 43 | * If you write code that depends on this, you do so at your own risk. |
duke@1 | 44 | * This code and its internal interfaces are subject to change or |
duke@1 | 45 | * deletion without notice.</b> |
duke@1 | 46 | */ |
duke@1 | 47 | public class Infer { |
duke@1 | 48 | protected static final Context.Key<Infer> inferKey = |
duke@1 | 49 | new Context.Key<Infer>(); |
duke@1 | 50 | |
duke@1 | 51 | /** A value for prototypes that admit any type, including polymorphic ones. */ |
duke@1 | 52 | public static final Type anyPoly = new Type(NONE, null); |
duke@1 | 53 | |
duke@1 | 54 | Symtab syms; |
duke@1 | 55 | Types types; |
mcimadamore@396 | 56 | Check chk; |
mcimadamore@299 | 57 | Resolve rs; |
mcimadamore@89 | 58 | JCDiagnostic.Factory diags; |
duke@1 | 59 | |
duke@1 | 60 | public static Infer instance(Context context) { |
duke@1 | 61 | Infer instance = context.get(inferKey); |
duke@1 | 62 | if (instance == null) |
duke@1 | 63 | instance = new Infer(context); |
duke@1 | 64 | return instance; |
duke@1 | 65 | } |
duke@1 | 66 | |
duke@1 | 67 | protected Infer(Context context) { |
duke@1 | 68 | context.put(inferKey, this); |
duke@1 | 69 | syms = Symtab.instance(context); |
duke@1 | 70 | types = Types.instance(context); |
mcimadamore@299 | 71 | rs = Resolve.instance(context); |
mcimadamore@396 | 72 | chk = Check.instance(context); |
mcimadamore@89 | 73 | diags = JCDiagnostic.Factory.instance(context); |
mcimadamore@89 | 74 | ambiguousNoInstanceException = |
mcimadamore@89 | 75 | new NoInstanceException(true, diags); |
mcimadamore@89 | 76 | unambiguousNoInstanceException = |
mcimadamore@89 | 77 | new NoInstanceException(false, diags); |
mcimadamore@299 | 78 | invalidInstanceException = |
mcimadamore@299 | 79 | new InvalidInstanceException(diags); |
mcimadamore@299 | 80 | |
duke@1 | 81 | } |
duke@1 | 82 | |
mcimadamore@689 | 83 | public static class InferenceException extends Resolve.InapplicableMethodException { |
duke@1 | 84 | private static final long serialVersionUID = 0; |
duke@1 | 85 | |
mcimadamore@299 | 86 | InferenceException(JCDiagnostic.Factory diags) { |
mcimadamore@689 | 87 | super(diags); |
duke@1 | 88 | } |
mcimadamore@299 | 89 | } |
mcimadamore@299 | 90 | |
mcimadamore@299 | 91 | public static class NoInstanceException extends InferenceException { |
mcimadamore@299 | 92 | private static final long serialVersionUID = 1; |
mcimadamore@299 | 93 | |
mcimadamore@299 | 94 | boolean isAmbiguous; // exist several incomparable best instances? |
mcimadamore@299 | 95 | |
mcimadamore@299 | 96 | NoInstanceException(boolean isAmbiguous, JCDiagnostic.Factory diags) { |
mcimadamore@299 | 97 | super(diags); |
mcimadamore@299 | 98 | this.isAmbiguous = isAmbiguous; |
duke@1 | 99 | } |
duke@1 | 100 | } |
mcimadamore@299 | 101 | |
mcimadamore@299 | 102 | public static class InvalidInstanceException extends InferenceException { |
mcimadamore@299 | 103 | private static final long serialVersionUID = 2; |
mcimadamore@299 | 104 | |
mcimadamore@299 | 105 | InvalidInstanceException(JCDiagnostic.Factory diags) { |
mcimadamore@299 | 106 | super(diags); |
mcimadamore@299 | 107 | } |
mcimadamore@299 | 108 | } |
mcimadamore@299 | 109 | |
mcimadamore@89 | 110 | private final NoInstanceException ambiguousNoInstanceException; |
mcimadamore@89 | 111 | private final NoInstanceException unambiguousNoInstanceException; |
mcimadamore@299 | 112 | private final InvalidInstanceException invalidInstanceException; |
duke@1 | 113 | |
duke@1 | 114 | /*************************************************************************** |
duke@1 | 115 | * Auxiliary type values and classes |
duke@1 | 116 | ***************************************************************************/ |
duke@1 | 117 | |
duke@1 | 118 | /** A mapping that turns type variables into undetermined type variables. |
duke@1 | 119 | */ |
duke@1 | 120 | Mapping fromTypeVarFun = new Mapping("fromTypeVarFun") { |
duke@1 | 121 | public Type apply(Type t) { |
duke@1 | 122 | if (t.tag == TYPEVAR) return new UndetVar(t); |
duke@1 | 123 | else return t.map(this); |
duke@1 | 124 | } |
duke@1 | 125 | }; |
duke@1 | 126 | |
duke@1 | 127 | /** A mapping that returns its type argument with every UndetVar replaced |
duke@1 | 128 | * by its `inst' field. Throws a NoInstanceException |
duke@1 | 129 | * if this not possible because an `inst' field is null. |
mcimadamore@635 | 130 | * Note: mutually referring undertvars will be left uninstantiated |
mcimadamore@635 | 131 | * (that is, they will be replaced by the underlying type-variable). |
duke@1 | 132 | */ |
mcimadamore@635 | 133 | |
duke@1 | 134 | Mapping getInstFun = new Mapping("getInstFun") { |
duke@1 | 135 | public Type apply(Type t) { |
duke@1 | 136 | switch (t.tag) { |
mcimadamore@635 | 137 | case UNKNOWN: |
duke@1 | 138 | throw ambiguousNoInstanceException |
mcimadamore@635 | 139 | .setMessage("undetermined.type"); |
mcimadamore@635 | 140 | case UNDETVAR: |
mcimadamore@635 | 141 | UndetVar that = (UndetVar) t; |
mcimadamore@635 | 142 | if (that.inst == null) |
mcimadamore@635 | 143 | throw ambiguousNoInstanceException |
mcimadamore@635 | 144 | .setMessage("type.variable.has.undetermined.type", |
mcimadamore@635 | 145 | that.qtype); |
mcimadamore@635 | 146 | return isConstraintCyclic(that) ? |
mcimadamore@635 | 147 | that.qtype : |
mcimadamore@635 | 148 | apply(that.inst); |
mcimadamore@635 | 149 | default: |
mcimadamore@635 | 150 | return t.map(this); |
duke@1 | 151 | } |
duke@1 | 152 | } |
mcimadamore@635 | 153 | |
mcimadamore@635 | 154 | private boolean isConstraintCyclic(UndetVar uv) { |
mcimadamore@635 | 155 | Types.UnaryVisitor<Boolean> constraintScanner = |
mcimadamore@635 | 156 | new Types.UnaryVisitor<Boolean>() { |
mcimadamore@635 | 157 | |
mcimadamore@635 | 158 | List<Type> seen = List.nil(); |
mcimadamore@635 | 159 | |
mcimadamore@635 | 160 | Boolean visit(List<Type> ts) { |
mcimadamore@635 | 161 | for (Type t : ts) { |
mcimadamore@635 | 162 | if (visit(t)) return true; |
mcimadamore@635 | 163 | } |
mcimadamore@635 | 164 | return false; |
mcimadamore@635 | 165 | } |
mcimadamore@635 | 166 | |
mcimadamore@635 | 167 | public Boolean visitType(Type t, Void ignored) { |
mcimadamore@635 | 168 | return false; |
mcimadamore@635 | 169 | } |
mcimadamore@635 | 170 | |
mcimadamore@635 | 171 | @Override |
mcimadamore@635 | 172 | public Boolean visitClassType(ClassType t, Void ignored) { |
mcimadamore@635 | 173 | if (t.isCompound()) { |
mcimadamore@635 | 174 | return visit(types.supertype(t)) || |
mcimadamore@635 | 175 | visit(types.interfaces(t)); |
mcimadamore@635 | 176 | } else { |
mcimadamore@635 | 177 | return visit(t.getTypeArguments()); |
mcimadamore@635 | 178 | } |
mcimadamore@635 | 179 | } |
mcimadamore@635 | 180 | @Override |
mcimadamore@635 | 181 | public Boolean visitWildcardType(WildcardType t, Void ignored) { |
mcimadamore@635 | 182 | return visit(t.type); |
mcimadamore@635 | 183 | } |
mcimadamore@635 | 184 | |
mcimadamore@635 | 185 | @Override |
mcimadamore@635 | 186 | public Boolean visitUndetVar(UndetVar t, Void ignored) { |
mcimadamore@635 | 187 | if (seen.contains(t)) { |
mcimadamore@635 | 188 | return true; |
mcimadamore@635 | 189 | } else { |
mcimadamore@635 | 190 | seen = seen.prepend(t); |
mcimadamore@635 | 191 | return visit(t.inst); |
mcimadamore@635 | 192 | } |
mcimadamore@635 | 193 | } |
mcimadamore@635 | 194 | }; |
mcimadamore@635 | 195 | return constraintScanner.visit(uv); |
mcimadamore@635 | 196 | } |
duke@1 | 197 | }; |
duke@1 | 198 | |
duke@1 | 199 | /*************************************************************************** |
duke@1 | 200 | * Mini/Maximization of UndetVars |
duke@1 | 201 | ***************************************************************************/ |
duke@1 | 202 | |
duke@1 | 203 | /** Instantiate undetermined type variable to its minimal upper bound. |
duke@1 | 204 | * Throw a NoInstanceException if this not possible. |
duke@1 | 205 | */ |
duke@1 | 206 | void maximizeInst(UndetVar that, Warner warn) throws NoInstanceException { |
duke@1 | 207 | if (that.inst == null) { |
duke@1 | 208 | if (that.hibounds.isEmpty()) |
duke@1 | 209 | that.inst = syms.objectType; |
duke@1 | 210 | else if (that.hibounds.tail.isEmpty()) |
duke@1 | 211 | that.inst = that.hibounds.head; |
mcimadamore@210 | 212 | else |
mcimadamore@210 | 213 | that.inst = types.glb(that.hibounds); |
duke@1 | 214 | } |
mcimadamore@210 | 215 | if (that.inst == null || |
mcimadamore@298 | 216 | that.inst.isErroneous()) |
mcimadamore@210 | 217 | throw ambiguousNoInstanceException |
mcimadamore@210 | 218 | .setMessage("no.unique.maximal.instance.exists", |
mcimadamore@210 | 219 | that.qtype, that.hibounds); |
duke@1 | 220 | } |
duke@1 | 221 | //where |
duke@1 | 222 | private boolean isSubClass(Type t, final List<Type> ts) { |
duke@1 | 223 | t = t.baseType(); |
duke@1 | 224 | if (t.tag == TYPEVAR) { |
duke@1 | 225 | List<Type> bounds = types.getBounds((TypeVar)t); |
duke@1 | 226 | for (Type s : ts) { |
duke@1 | 227 | if (!types.isSameType(t, s.baseType())) { |
duke@1 | 228 | for (Type bound : bounds) { |
duke@1 | 229 | if (!isSubClass(bound, List.of(s.baseType()))) |
duke@1 | 230 | return false; |
duke@1 | 231 | } |
duke@1 | 232 | } |
duke@1 | 233 | } |
duke@1 | 234 | } else { |
duke@1 | 235 | for (Type s : ts) { |
duke@1 | 236 | if (!t.tsym.isSubClass(s.baseType().tsym, types)) |
duke@1 | 237 | return false; |
duke@1 | 238 | } |
duke@1 | 239 | } |
duke@1 | 240 | return true; |
duke@1 | 241 | } |
duke@1 | 242 | |
jjg@110 | 243 | /** Instantiate undetermined type variable to the lub of all its lower bounds. |
duke@1 | 244 | * Throw a NoInstanceException if this not possible. |
duke@1 | 245 | */ |
duke@1 | 246 | void minimizeInst(UndetVar that, Warner warn) throws NoInstanceException { |
duke@1 | 247 | if (that.inst == null) { |
duke@1 | 248 | if (that.lobounds.isEmpty()) |
duke@1 | 249 | that.inst = syms.botType; |
duke@1 | 250 | else if (that.lobounds.tail.isEmpty()) |
mcimadamore@5 | 251 | that.inst = that.lobounds.head.isPrimitive() ? syms.errType : that.lobounds.head; |
duke@1 | 252 | else { |
duke@1 | 253 | that.inst = types.lub(that.lobounds); |
mcimadamore@5 | 254 | } |
jjg@110 | 255 | if (that.inst == null || that.inst.tag == ERROR) |
duke@1 | 256 | throw ambiguousNoInstanceException |
duke@1 | 257 | .setMessage("no.unique.minimal.instance.exists", |
duke@1 | 258 | that.qtype, that.lobounds); |
duke@1 | 259 | // VGJ: sort of inlined maximizeInst() below. Adding |
duke@1 | 260 | // bounds can cause lobounds that are above hibounds. |
duke@1 | 261 | if (that.hibounds.isEmpty()) |
duke@1 | 262 | return; |
duke@1 | 263 | Type hb = null; |
duke@1 | 264 | if (that.hibounds.tail.isEmpty()) |
duke@1 | 265 | hb = that.hibounds.head; |
duke@1 | 266 | else for (List<Type> bs = that.hibounds; |
duke@1 | 267 | bs.nonEmpty() && hb == null; |
duke@1 | 268 | bs = bs.tail) { |
duke@1 | 269 | if (isSubClass(bs.head, that.hibounds)) |
duke@1 | 270 | hb = types.fromUnknownFun.apply(bs.head); |
duke@1 | 271 | } |
duke@1 | 272 | if (hb == null || |
duke@1 | 273 | !types.isSubtypeUnchecked(hb, that.hibounds, warn) || |
duke@1 | 274 | !types.isSubtypeUnchecked(that.inst, hb, warn)) |
duke@1 | 275 | throw ambiguousNoInstanceException; |
duke@1 | 276 | } |
duke@1 | 277 | } |
duke@1 | 278 | |
duke@1 | 279 | /*************************************************************************** |
duke@1 | 280 | * Exported Methods |
duke@1 | 281 | ***************************************************************************/ |
duke@1 | 282 | |
duke@1 | 283 | /** Try to instantiate expression type `that' to given type `to'. |
duke@1 | 284 | * If a maximal instantiation exists which makes this type |
duke@1 | 285 | * a subtype of type `to', return the instantiated type. |
duke@1 | 286 | * If no instantiation exists, or if several incomparable |
duke@1 | 287 | * best instantiations exist throw a NoInstanceException. |
duke@1 | 288 | */ |
duke@1 | 289 | public Type instantiateExpr(ForAll that, |
duke@1 | 290 | Type to, |
mcimadamore@299 | 291 | Warner warn) throws InferenceException { |
duke@1 | 292 | List<Type> undetvars = Type.map(that.tvars, fromTypeVarFun); |
duke@1 | 293 | for (List<Type> l = undetvars; l.nonEmpty(); l = l.tail) { |
mcimadamore@396 | 294 | UndetVar uv = (UndetVar) l.head; |
mcimadamore@396 | 295 | TypeVar tv = (TypeVar)uv.qtype; |
duke@1 | 296 | ListBuffer<Type> hibounds = new ListBuffer<Type>(); |
mcimadamore@615 | 297 | for (Type t : that.getConstraints(tv, ConstraintKind.EXTENDS)) { |
mcimadamore@635 | 298 | hibounds.append(types.subst(t, that.tvars, undetvars)); |
duke@1 | 299 | } |
mcimadamore@635 | 300 | |
mcimadamore@396 | 301 | List<Type> inst = that.getConstraints(tv, ConstraintKind.EQUAL); |
mcimadamore@396 | 302 | if (inst.nonEmpty() && inst.head.tag != BOT) { |
mcimadamore@396 | 303 | uv.inst = inst.head; |
mcimadamore@396 | 304 | } |
mcimadamore@396 | 305 | uv.hibounds = hibounds.toList(); |
duke@1 | 306 | } |
duke@1 | 307 | Type qtype1 = types.subst(that.qtype, that.tvars, undetvars); |
mcimadamore@753 | 308 | if (!types.isSubtype(qtype1, |
mcimadamore@753 | 309 | qtype1.tag == UNDETVAR ? types.boxedTypeOrType(to) : to)) { |
duke@1 | 310 | throw unambiguousNoInstanceException |
mcimadamore@689 | 311 | .setMessage("infer.no.conforming.instance.exists", |
duke@1 | 312 | that.tvars, that.qtype, to); |
duke@1 | 313 | } |
duke@1 | 314 | for (List<Type> l = undetvars; l.nonEmpty(); l = l.tail) |
duke@1 | 315 | maximizeInst((UndetVar) l.head, warn); |
duke@1 | 316 | // System.out.println(" = " + qtype1.map(getInstFun));//DEBUG |
duke@1 | 317 | |
duke@1 | 318 | // check bounds |
duke@1 | 319 | List<Type> targs = Type.map(undetvars, getInstFun); |
mcimadamore@635 | 320 | if (Type.containsAny(targs, that.tvars)) { |
mcimadamore@635 | 321 | //replace uninferred type-vars |
mcimadamore@635 | 322 | targs = types.subst(targs, |
mcimadamore@635 | 323 | that.tvars, |
mcimadamore@635 | 324 | instaniateAsUninferredVars(undetvars, that.tvars)); |
mcimadamore@635 | 325 | } |
mcimadamore@396 | 326 | return chk.checkType(warn.pos(), that.inst(targs, types), to); |
duke@1 | 327 | } |
mcimadamore@635 | 328 | //where |
mcimadamore@635 | 329 | private List<Type> instaniateAsUninferredVars(List<Type> undetvars, List<Type> tvars) { |
mcimadamore@635 | 330 | ListBuffer<Type> new_targs = ListBuffer.lb(); |
mcimadamore@635 | 331 | //step 1 - create syntethic captured vars |
mcimadamore@635 | 332 | for (Type t : undetvars) { |
mcimadamore@635 | 333 | UndetVar uv = (UndetVar)t; |
mcimadamore@635 | 334 | Type newArg = new CapturedType(t.tsym.name, t.tsym, uv.inst, syms.botType, null); |
mcimadamore@635 | 335 | new_targs = new_targs.append(newArg); |
mcimadamore@635 | 336 | } |
mcimadamore@635 | 337 | //step 2 - replace synthetic vars in their bounds |
mcimadamore@635 | 338 | for (Type t : new_targs.toList()) { |
mcimadamore@635 | 339 | CapturedType ct = (CapturedType)t; |
mcimadamore@635 | 340 | ct.bound = types.subst(ct.bound, tvars, new_targs.toList()); |
mcimadamore@635 | 341 | WildcardType wt = new WildcardType(ct.bound, BoundKind.EXTENDS, syms.boundClass); |
mcimadamore@635 | 342 | ct.wildcard = wt; |
mcimadamore@635 | 343 | } |
mcimadamore@635 | 344 | return new_targs.toList(); |
mcimadamore@635 | 345 | } |
duke@1 | 346 | |
duke@1 | 347 | /** Instantiate method type `mt' by finding instantiations of |
duke@1 | 348 | * `tvars' so that method can be applied to `argtypes'. |
duke@1 | 349 | */ |
mcimadamore@547 | 350 | public Type instantiateMethod(final Env<AttrContext> env, |
mcimadamore@547 | 351 | List<Type> tvars, |
duke@1 | 352 | MethodType mt, |
mcimadamore@580 | 353 | final Symbol msym, |
mcimadamore@299 | 354 | final List<Type> argtypes, |
mcimadamore@299 | 355 | final boolean allowBoxing, |
mcimadamore@299 | 356 | final boolean useVarargs, |
mcimadamore@299 | 357 | final Warner warn) throws InferenceException { |
duke@1 | 358 | //-System.err.println("instantiateMethod(" + tvars + ", " + mt + ", " + argtypes + ")"); //DEBUG |
duke@1 | 359 | List<Type> undetvars = Type.map(tvars, fromTypeVarFun); |
duke@1 | 360 | List<Type> formals = mt.argtypes; |
mcimadamore@299 | 361 | //need to capture exactly once - otherwise subsequent |
mcimadamore@299 | 362 | //applicability checks might fail |
mcimadamore@299 | 363 | final List<Type> capturedArgs = types.capture(argtypes); |
mcimadamore@299 | 364 | List<Type> actuals = capturedArgs; |
mcimadamore@299 | 365 | List<Type> actualsNoCapture = argtypes; |
duke@1 | 366 | // instantiate all polymorphic argument types and |
duke@1 | 367 | // set up lower bounds constraints for undetvars |
duke@1 | 368 | Type varargsFormal = useVarargs ? formals.last() : null; |
mcimadamore@689 | 369 | if (varargsFormal == null && |
mcimadamore@689 | 370 | actuals.size() != formals.size()) { |
mcimadamore@689 | 371 | throw unambiguousNoInstanceException |
mcimadamore@689 | 372 | .setMessage("infer.arg.length.mismatch"); |
mcimadamore@689 | 373 | } |
mcimadamore@299 | 374 | while (actuals.nonEmpty() && formals.head != varargsFormal) { |
mcimadamore@299 | 375 | Type formal = formals.head; |
mcimadamore@299 | 376 | Type actual = actuals.head.baseType(); |
mcimadamore@299 | 377 | Type actualNoCapture = actualsNoCapture.head.baseType(); |
mcimadamore@299 | 378 | if (actual.tag == FORALL) |
mcimadamore@299 | 379 | actual = instantiateArg((ForAll)actual, formal, tvars, warn); |
mcimadamore@299 | 380 | Type undetFormal = types.subst(formal, tvars, undetvars); |
duke@1 | 381 | boolean works = allowBoxing |
mcimadamore@299 | 382 | ? types.isConvertible(actual, undetFormal, warn) |
mcimadamore@299 | 383 | : types.isSubtypeUnchecked(actual, undetFormal, warn); |
duke@1 | 384 | if (!works) { |
duke@1 | 385 | throw unambiguousNoInstanceException |
mcimadamore@689 | 386 | .setMessage("infer.no.conforming.assignment.exists", |
mcimadamore@299 | 387 | tvars, actualNoCapture, formal); |
duke@1 | 388 | } |
duke@1 | 389 | formals = formals.tail; |
mcimadamore@299 | 390 | actuals = actuals.tail; |
mcimadamore@299 | 391 | actualsNoCapture = actualsNoCapture.tail; |
duke@1 | 392 | } |
mcimadamore@689 | 393 | |
mcimadamore@689 | 394 | if (formals.head != varargsFormal) // not enough args |
mcimadamore@689 | 395 | throw unambiguousNoInstanceException.setMessage("infer.arg.length.mismatch"); |
duke@1 | 396 | |
duke@1 | 397 | // for varargs arguments as well |
duke@1 | 398 | if (useVarargs) { |
mcimadamore@299 | 399 | Type elemType = types.elemtype(varargsFormal); |
mcimadamore@299 | 400 | Type elemUndet = types.subst(elemType, tvars, undetvars); |
mcimadamore@299 | 401 | while (actuals.nonEmpty()) { |
mcimadamore@299 | 402 | Type actual = actuals.head.baseType(); |
mcimadamore@299 | 403 | Type actualNoCapture = actualsNoCapture.head.baseType(); |
mcimadamore@299 | 404 | if (actual.tag == FORALL) |
mcimadamore@299 | 405 | actual = instantiateArg((ForAll)actual, elemType, tvars, warn); |
mcimadamore@299 | 406 | boolean works = types.isConvertible(actual, elemUndet, warn); |
duke@1 | 407 | if (!works) { |
duke@1 | 408 | throw unambiguousNoInstanceException |
mcimadamore@689 | 409 | .setMessage("infer.no.conforming.assignment.exists", |
mcimadamore@299 | 410 | tvars, actualNoCapture, elemType); |
duke@1 | 411 | } |
mcimadamore@299 | 412 | actuals = actuals.tail; |
mcimadamore@299 | 413 | actualsNoCapture = actualsNoCapture.tail; |
duke@1 | 414 | } |
duke@1 | 415 | } |
duke@1 | 416 | |
duke@1 | 417 | // minimize as yet undetermined type variables |
duke@1 | 418 | for (Type t : undetvars) |
duke@1 | 419 | minimizeInst((UndetVar) t, warn); |
duke@1 | 420 | |
duke@1 | 421 | /** Type variables instantiated to bottom */ |
duke@1 | 422 | ListBuffer<Type> restvars = new ListBuffer<Type>(); |
duke@1 | 423 | |
mcimadamore@396 | 424 | /** Undet vars instantiated to bottom */ |
mcimadamore@396 | 425 | final ListBuffer<Type> restundet = new ListBuffer<Type>(); |
mcimadamore@396 | 426 | |
duke@1 | 427 | /** Instantiated types or TypeVars if under-constrained */ |
duke@1 | 428 | ListBuffer<Type> insttypes = new ListBuffer<Type>(); |
duke@1 | 429 | |
duke@1 | 430 | /** Instantiated types or UndetVars if under-constrained */ |
duke@1 | 431 | ListBuffer<Type> undettypes = new ListBuffer<Type>(); |
duke@1 | 432 | |
duke@1 | 433 | for (Type t : undetvars) { |
duke@1 | 434 | UndetVar uv = (UndetVar)t; |
duke@1 | 435 | if (uv.inst.tag == BOT) { |
duke@1 | 436 | restvars.append(uv.qtype); |
mcimadamore@396 | 437 | restundet.append(uv); |
duke@1 | 438 | insttypes.append(uv.qtype); |
duke@1 | 439 | undettypes.append(uv); |
duke@1 | 440 | uv.inst = null; |
duke@1 | 441 | } else { |
duke@1 | 442 | insttypes.append(uv.inst); |
duke@1 | 443 | undettypes.append(uv.inst); |
duke@1 | 444 | } |
duke@1 | 445 | } |
duke@1 | 446 | checkWithinBounds(tvars, undettypes.toList(), warn); |
duke@1 | 447 | |
mcimadamore@299 | 448 | mt = (MethodType)types.subst(mt, tvars, insttypes.toList()); |
mcimadamore@299 | 449 | |
duke@1 | 450 | if (!restvars.isEmpty()) { |
duke@1 | 451 | // if there are uninstantiated variables, |
duke@1 | 452 | // quantify result type with them |
mcimadamore@299 | 453 | final List<Type> inferredTypes = insttypes.toList(); |
mcimadamore@299 | 454 | final List<Type> all_tvars = tvars; //this is the wrong tvars |
mcimadamore@299 | 455 | final MethodType mt2 = new MethodType(mt.argtypes, null, mt.thrown, syms.methodClass); |
mcimadamore@299 | 456 | mt2.restype = new ForAll(restvars.toList(), mt.restype) { |
mcimadamore@299 | 457 | @Override |
mcimadamore@396 | 458 | public List<Type> getConstraints(TypeVar tv, ConstraintKind ck) { |
mcimadamore@396 | 459 | for (Type t : restundet.toList()) { |
mcimadamore@396 | 460 | UndetVar uv = (UndetVar)t; |
mcimadamore@396 | 461 | if (uv.qtype == tv) { |
mcimadamore@396 | 462 | switch (ck) { |
mcimadamore@615 | 463 | case EXTENDS: return uv.hibounds.appendList(types.subst(types.getBounds(tv), all_tvars, inferredTypes)); |
mcimadamore@396 | 464 | case SUPER: return uv.lobounds; |
mcimadamore@396 | 465 | case EQUAL: return uv.inst != null ? List.of(uv.inst) : List.<Type>nil(); |
mcimadamore@396 | 466 | } |
mcimadamore@396 | 467 | } |
mcimadamore@396 | 468 | } |
mcimadamore@396 | 469 | return List.nil(); |
mcimadamore@396 | 470 | } |
mcimadamore@396 | 471 | |
mcimadamore@396 | 472 | @Override |
mcimadamore@299 | 473 | public Type inst(List<Type> inferred, Types types) throws NoInstanceException { |
mcimadamore@299 | 474 | List<Type> formals = types.subst(mt2.argtypes, tvars, inferred); |
mcimadamore@396 | 475 | if (!rs.argumentsAcceptable(capturedArgs, formals, |
mcimadamore@299 | 476 | allowBoxing, useVarargs, warn)) { |
mcimadamore@299 | 477 | // inferred method is not applicable |
mcimadamore@299 | 478 | throw invalidInstanceException.setMessage("inferred.do.not.conform.to.params", formals, argtypes); |
mcimadamore@396 | 479 | } |
mcimadamore@396 | 480 | // check that inferred bounds conform to their bounds |
mcimadamore@396 | 481 | checkWithinBounds(all_tvars, |
mcimadamore@299 | 482 | types.subst(inferredTypes, tvars, inferred), warn); |
mcimadamore@547 | 483 | if (useVarargs) { |
mcimadamore@795 | 484 | chk.checkVararg(env.tree.pos(), formals, msym); |
mcimadamore@547 | 485 | } |
mcimadamore@396 | 486 | return super.inst(inferred, types); |
mcimadamore@299 | 487 | }}; |
mcimadamore@299 | 488 | return mt2; |
duke@1 | 489 | } |
mcimadamore@299 | 490 | else if (!rs.argumentsAcceptable(capturedArgs, mt.getParameterTypes(), allowBoxing, useVarargs, warn)) { |
mcimadamore@299 | 491 | // inferred method is not applicable |
mcimadamore@299 | 492 | throw invalidInstanceException.setMessage("inferred.do.not.conform.to.params", mt.getParameterTypes(), argtypes); |
mcimadamore@299 | 493 | } |
mcimadamore@299 | 494 | else { |
mcimadamore@299 | 495 | // return instantiated version of method type |
mcimadamore@299 | 496 | return mt; |
mcimadamore@299 | 497 | } |
duke@1 | 498 | } |
duke@1 | 499 | //where |
duke@1 | 500 | |
duke@1 | 501 | /** Try to instantiate argument type `that' to given type `to'. |
duke@1 | 502 | * If this fails, try to insantiate `that' to `to' where |
duke@1 | 503 | * every occurrence of a type variable in `tvars' is replaced |
duke@1 | 504 | * by an unknown type. |
duke@1 | 505 | */ |
duke@1 | 506 | private Type instantiateArg(ForAll that, |
duke@1 | 507 | Type to, |
duke@1 | 508 | List<Type> tvars, |
mcimadamore@299 | 509 | Warner warn) throws InferenceException { |
duke@1 | 510 | List<Type> targs; |
duke@1 | 511 | try { |
duke@1 | 512 | return instantiateExpr(that, to, warn); |
duke@1 | 513 | } catch (NoInstanceException ex) { |
duke@1 | 514 | Type to1 = to; |
duke@1 | 515 | for (List<Type> l = tvars; l.nonEmpty(); l = l.tail) |
duke@1 | 516 | to1 = types.subst(to1, List.of(l.head), List.of(syms.unknownType)); |
duke@1 | 517 | return instantiateExpr(that, to1, warn); |
duke@1 | 518 | } |
duke@1 | 519 | } |
duke@1 | 520 | |
duke@1 | 521 | /** check that type parameters are within their bounds. |
duke@1 | 522 | */ |
mcimadamore@615 | 523 | void checkWithinBounds(List<Type> tvars, |
duke@1 | 524 | List<Type> arguments, |
duke@1 | 525 | Warner warn) |
mcimadamore@299 | 526 | throws InvalidInstanceException { |
duke@1 | 527 | for (List<Type> tvs = tvars, args = arguments; |
duke@1 | 528 | tvs.nonEmpty(); |
duke@1 | 529 | tvs = tvs.tail, args = args.tail) { |
duke@1 | 530 | if (args.head instanceof UndetVar) continue; |
duke@1 | 531 | List<Type> bounds = types.subst(types.getBounds((TypeVar)tvs.head), tvars, arguments); |
duke@1 | 532 | if (!types.isSubtypeUnchecked(args.head, bounds, warn)) |
mcimadamore@299 | 533 | throw invalidInstanceException |
duke@1 | 534 | .setMessage("inferred.do.not.conform.to.bounds", |
mcimadamore@299 | 535 | args.head, bounds); |
duke@1 | 536 | } |
duke@1 | 537 | } |
mcimadamore@674 | 538 | |
mcimadamore@674 | 539 | /** |
mcimadamore@674 | 540 | * Compute a synthetic method type corresponding to the requested polymorphic |
mcimadamore@674 | 541 | * method signature. If no explicit return type is supplied, a provisional |
mcimadamore@674 | 542 | * return type is computed (just Object in case of non-transitional 292) |
mcimadamore@674 | 543 | */ |
mcimadamore@674 | 544 | Type instantiatePolymorphicSignatureInstance(Env<AttrContext> env, Type site, |
mcimadamore@674 | 545 | Name name, |
mcimadamore@674 | 546 | MethodSymbol spMethod, // sig. poly. method or null if none |
mcimadamore@674 | 547 | List<Type> argtypes, |
mcimadamore@674 | 548 | List<Type> typeargtypes) { |
mcimadamore@674 | 549 | final Type restype; |
mcimadamore@674 | 550 | if (rs.allowTransitionalJSR292 && typeargtypes.nonEmpty()) { |
mcimadamore@674 | 551 | restype = typeargtypes.head; |
mcimadamore@674 | 552 | } else { |
mcimadamore@674 | 553 | //The return type for a polymorphic signature call is computed from |
mcimadamore@674 | 554 | //the enclosing tree E, as follows: if E is a cast, then use the |
mcimadamore@674 | 555 | //target type of the cast expression as a return type; if E is an |
mcimadamore@674 | 556 | //expression statement, the return type is 'void' - otherwise the |
mcimadamore@716 | 557 | //return type is simply 'Object'. A correctness check ensures that |
mcimadamore@716 | 558 | //env.next refers to the lexically enclosing environment in which |
mcimadamore@716 | 559 | //the polymorphic signature call environment is nested. |
mcimadamore@716 | 560 | |
mcimadamore@716 | 561 | switch (env.next.tree.getTag()) { |
mcimadamore@674 | 562 | case JCTree.TYPECAST: |
mcimadamore@716 | 563 | JCTypeCast castTree = (JCTypeCast)env.next.tree; |
mcimadamore@716 | 564 | restype = (castTree.expr == env.tree) ? |
mcimadamore@716 | 565 | castTree.clazz.type : |
mcimadamore@716 | 566 | syms.objectType; |
mcimadamore@716 | 567 | break; |
mcimadamore@674 | 568 | case JCTree.EXEC: |
mcimadamore@716 | 569 | JCTree.JCExpressionStatement execTree = |
mcimadamore@716 | 570 | (JCTree.JCExpressionStatement)env.next.tree; |
mcimadamore@716 | 571 | restype = (execTree.expr == env.tree) ? |
mcimadamore@716 | 572 | syms.voidType : |
mcimadamore@716 | 573 | syms.objectType; |
mcimadamore@716 | 574 | break; |
mcimadamore@674 | 575 | default: |
mcimadamore@674 | 576 | restype = syms.objectType; |
mcimadamore@674 | 577 | } |
mcimadamore@674 | 578 | } |
mcimadamore@674 | 579 | |
mcimadamore@674 | 580 | List<Type> paramtypes = Type.map(argtypes, implicitArgType); |
mcimadamore@674 | 581 | List<Type> exType = spMethod != null ? |
mcimadamore@674 | 582 | spMethod.getThrownTypes() : |
mcimadamore@674 | 583 | List.of(syms.throwableType); // make it throw all exceptions |
mcimadamore@674 | 584 | |
mcimadamore@674 | 585 | MethodType mtype = new MethodType(paramtypes, |
mcimadamore@674 | 586 | restype, |
mcimadamore@674 | 587 | exType, |
mcimadamore@674 | 588 | syms.methodClass); |
mcimadamore@674 | 589 | return mtype; |
mcimadamore@674 | 590 | } |
mcimadamore@674 | 591 | //where |
mcimadamore@674 | 592 | Mapping implicitArgType = new Mapping ("implicitArgType") { |
mcimadamore@674 | 593 | public Type apply(Type t) { |
mcimadamore@674 | 594 | t = types.erasure(t); |
mcimadamore@674 | 595 | if (t.tag == BOT) |
mcimadamore@674 | 596 | // nulls type as the marker type Null (which has no instances) |
mcimadamore@674 | 597 | // infer as java.lang.Void for now |
mcimadamore@674 | 598 | t = types.boxedClass(syms.voidType).type; |
mcimadamore@674 | 599 | return t; |
mcimadamore@674 | 600 | } |
mcimadamore@674 | 601 | }; |
duke@1 | 602 | } |