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

Tue, 13 Sep 2011 14:15:39 +0100

author
mcimadamore
date
Tue, 13 Sep 2011 14:15:39 +0100
changeset 1087
3a2200681d69
parent 1006
a2d422d480cb
child 1114
05814303a056
permissions
-rw-r--r--

7086601: Error message bug: cause for method mismatch is 'null'
Summary: Inference error during lub() does not set 'cause' for method resolution diagnostic
Reviewed-by: jjg

duke@1 1 /*
mcimadamore@845 2 * Copyright (c) 1999, 2011, 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;
mcimadamore@820 30 import com.sun.tools.javac.tree.TreeInfo;
duke@1 31 import com.sun.tools.javac.util.*;
duke@1 32 import com.sun.tools.javac.util.List;
duke@1 33 import com.sun.tools.javac.code.*;
duke@1 34 import com.sun.tools.javac.code.Type.*;
mcimadamore@396 35 import com.sun.tools.javac.code.Type.ForAll.ConstraintKind;
mcimadamore@299 36 import com.sun.tools.javac.code.Symbol.*;
mcimadamore@89 37 import com.sun.tools.javac.util.JCDiagnostic;
duke@1 38
duke@1 39 import static com.sun.tools.javac.code.TypeTags.*;
duke@1 40
duke@1 41 /** Helper class for type parameter inference, used by the attribution phase.
duke@1 42 *
jjg@581 43 * <p><b>This is NOT part of any supported API.
jjg@581 44 * If you write code that depends on this, you do so at your own risk.
duke@1 45 * This code and its internal interfaces are subject to change or
duke@1 46 * deletion without notice.</b>
duke@1 47 */
duke@1 48 public class Infer {
duke@1 49 protected static final Context.Key<Infer> inferKey =
duke@1 50 new Context.Key<Infer>();
duke@1 51
duke@1 52 /** A value for prototypes that admit any type, including polymorphic ones. */
duke@1 53 public static final Type anyPoly = new Type(NONE, null);
duke@1 54
duke@1 55 Symtab syms;
duke@1 56 Types types;
mcimadamore@396 57 Check chk;
mcimadamore@299 58 Resolve rs;
mcimadamore@89 59 JCDiagnostic.Factory diags;
duke@1 60
duke@1 61 public static Infer instance(Context context) {
duke@1 62 Infer instance = context.get(inferKey);
duke@1 63 if (instance == null)
duke@1 64 instance = new Infer(context);
duke@1 65 return instance;
duke@1 66 }
duke@1 67
duke@1 68 protected Infer(Context context) {
duke@1 69 context.put(inferKey, this);
duke@1 70 syms = Symtab.instance(context);
duke@1 71 types = Types.instance(context);
mcimadamore@299 72 rs = Resolve.instance(context);
mcimadamore@396 73 chk = Check.instance(context);
mcimadamore@89 74 diags = JCDiagnostic.Factory.instance(context);
mcimadamore@89 75 ambiguousNoInstanceException =
mcimadamore@89 76 new NoInstanceException(true, diags);
mcimadamore@89 77 unambiguousNoInstanceException =
mcimadamore@89 78 new NoInstanceException(false, diags);
mcimadamore@299 79 invalidInstanceException =
mcimadamore@299 80 new InvalidInstanceException(diags);
mcimadamore@299 81
duke@1 82 }
duke@1 83
mcimadamore@689 84 public static class InferenceException extends Resolve.InapplicableMethodException {
duke@1 85 private static final long serialVersionUID = 0;
duke@1 86
mcimadamore@299 87 InferenceException(JCDiagnostic.Factory diags) {
mcimadamore@689 88 super(diags);
duke@1 89 }
mcimadamore@299 90 }
mcimadamore@299 91
mcimadamore@299 92 public static class NoInstanceException extends InferenceException {
mcimadamore@299 93 private static final long serialVersionUID = 1;
mcimadamore@299 94
mcimadamore@299 95 boolean isAmbiguous; // exist several incomparable best instances?
mcimadamore@299 96
mcimadamore@299 97 NoInstanceException(boolean isAmbiguous, JCDiagnostic.Factory diags) {
mcimadamore@299 98 super(diags);
mcimadamore@299 99 this.isAmbiguous = isAmbiguous;
duke@1 100 }
duke@1 101 }
mcimadamore@299 102
mcimadamore@299 103 public static class InvalidInstanceException extends InferenceException {
mcimadamore@299 104 private static final long serialVersionUID = 2;
mcimadamore@299 105
mcimadamore@299 106 InvalidInstanceException(JCDiagnostic.Factory diags) {
mcimadamore@299 107 super(diags);
mcimadamore@299 108 }
mcimadamore@299 109 }
mcimadamore@299 110
mcimadamore@89 111 private final NoInstanceException ambiguousNoInstanceException;
mcimadamore@89 112 private final NoInstanceException unambiguousNoInstanceException;
mcimadamore@299 113 private final InvalidInstanceException invalidInstanceException;
duke@1 114
duke@1 115 /***************************************************************************
duke@1 116 * Auxiliary type values and classes
duke@1 117 ***************************************************************************/
duke@1 118
duke@1 119 /** A mapping that turns type variables into undetermined type variables.
duke@1 120 */
duke@1 121 Mapping fromTypeVarFun = new Mapping("fromTypeVarFun") {
duke@1 122 public Type apply(Type t) {
duke@1 123 if (t.tag == TYPEVAR) return new UndetVar(t);
duke@1 124 else return t.map(this);
duke@1 125 }
duke@1 126 };
duke@1 127
duke@1 128 /** A mapping that returns its type argument with every UndetVar replaced
duke@1 129 * by its `inst' field. Throws a NoInstanceException
duke@1 130 * if this not possible because an `inst' field is null.
mcimadamore@635 131 * Note: mutually referring undertvars will be left uninstantiated
mcimadamore@635 132 * (that is, they will be replaced by the underlying type-variable).
duke@1 133 */
mcimadamore@635 134
duke@1 135 Mapping getInstFun = new Mapping("getInstFun") {
duke@1 136 public Type apply(Type t) {
duke@1 137 switch (t.tag) {
mcimadamore@635 138 case UNKNOWN:
duke@1 139 throw ambiguousNoInstanceException
mcimadamore@635 140 .setMessage("undetermined.type");
mcimadamore@635 141 case UNDETVAR:
mcimadamore@635 142 UndetVar that = (UndetVar) t;
mcimadamore@635 143 if (that.inst == null)
mcimadamore@635 144 throw ambiguousNoInstanceException
mcimadamore@635 145 .setMessage("type.variable.has.undetermined.type",
mcimadamore@635 146 that.qtype);
mcimadamore@635 147 return isConstraintCyclic(that) ?
mcimadamore@635 148 that.qtype :
mcimadamore@635 149 apply(that.inst);
mcimadamore@635 150 default:
mcimadamore@635 151 return t.map(this);
duke@1 152 }
duke@1 153 }
mcimadamore@635 154
mcimadamore@635 155 private boolean isConstraintCyclic(UndetVar uv) {
mcimadamore@635 156 Types.UnaryVisitor<Boolean> constraintScanner =
mcimadamore@635 157 new Types.UnaryVisitor<Boolean>() {
mcimadamore@635 158
mcimadamore@635 159 List<Type> seen = List.nil();
mcimadamore@635 160
mcimadamore@635 161 Boolean visit(List<Type> ts) {
mcimadamore@635 162 for (Type t : ts) {
mcimadamore@635 163 if (visit(t)) return true;
mcimadamore@635 164 }
mcimadamore@635 165 return false;
mcimadamore@635 166 }
mcimadamore@635 167
mcimadamore@635 168 public Boolean visitType(Type t, Void ignored) {
mcimadamore@635 169 return false;
mcimadamore@635 170 }
mcimadamore@635 171
mcimadamore@635 172 @Override
mcimadamore@635 173 public Boolean visitClassType(ClassType t, Void ignored) {
mcimadamore@635 174 if (t.isCompound()) {
mcimadamore@635 175 return visit(types.supertype(t)) ||
mcimadamore@635 176 visit(types.interfaces(t));
mcimadamore@635 177 } else {
mcimadamore@635 178 return visit(t.getTypeArguments());
mcimadamore@635 179 }
mcimadamore@635 180 }
mcimadamore@635 181 @Override
mcimadamore@635 182 public Boolean visitWildcardType(WildcardType t, Void ignored) {
mcimadamore@635 183 return visit(t.type);
mcimadamore@635 184 }
mcimadamore@635 185
mcimadamore@635 186 @Override
mcimadamore@635 187 public Boolean visitUndetVar(UndetVar t, Void ignored) {
mcimadamore@635 188 if (seen.contains(t)) {
mcimadamore@635 189 return true;
mcimadamore@635 190 } else {
mcimadamore@635 191 seen = seen.prepend(t);
mcimadamore@635 192 return visit(t.inst);
mcimadamore@635 193 }
mcimadamore@635 194 }
mcimadamore@635 195 };
mcimadamore@635 196 return constraintScanner.visit(uv);
mcimadamore@635 197 }
duke@1 198 };
duke@1 199
duke@1 200 /***************************************************************************
duke@1 201 * Mini/Maximization of UndetVars
duke@1 202 ***************************************************************************/
duke@1 203
duke@1 204 /** Instantiate undetermined type variable to its minimal upper bound.
duke@1 205 * Throw a NoInstanceException if this not possible.
duke@1 206 */
duke@1 207 void maximizeInst(UndetVar that, Warner warn) throws NoInstanceException {
mcimadamore@828 208 List<Type> hibounds = Type.filter(that.hibounds, errorFilter);
duke@1 209 if (that.inst == null) {
mcimadamore@828 210 if (hibounds.isEmpty())
duke@1 211 that.inst = syms.objectType;
mcimadamore@828 212 else if (hibounds.tail.isEmpty())
mcimadamore@828 213 that.inst = hibounds.head;
mcimadamore@210 214 else
mcimadamore@828 215 that.inst = types.glb(hibounds);
duke@1 216 }
mcimadamore@210 217 if (that.inst == null ||
mcimadamore@298 218 that.inst.isErroneous())
mcimadamore@210 219 throw ambiguousNoInstanceException
mcimadamore@210 220 .setMessage("no.unique.maximal.instance.exists",
mcimadamore@828 221 that.qtype, hibounds);
duke@1 222 }
duke@1 223 //where
duke@1 224 private boolean isSubClass(Type t, final List<Type> ts) {
duke@1 225 t = t.baseType();
duke@1 226 if (t.tag == TYPEVAR) {
duke@1 227 List<Type> bounds = types.getBounds((TypeVar)t);
duke@1 228 for (Type s : ts) {
duke@1 229 if (!types.isSameType(t, s.baseType())) {
duke@1 230 for (Type bound : bounds) {
duke@1 231 if (!isSubClass(bound, List.of(s.baseType())))
duke@1 232 return false;
duke@1 233 }
duke@1 234 }
duke@1 235 }
duke@1 236 } else {
duke@1 237 for (Type s : ts) {
duke@1 238 if (!t.tsym.isSubClass(s.baseType().tsym, types))
duke@1 239 return false;
duke@1 240 }
duke@1 241 }
duke@1 242 return true;
duke@1 243 }
duke@1 244
mcimadamore@828 245 private Filter<Type> errorFilter = new Filter<Type>() {
mcimadamore@828 246 @Override
mcimadamore@828 247 public boolean accepts(Type t) {
mcimadamore@828 248 return !t.isErroneous();
mcimadamore@828 249 }
mcimadamore@828 250 };
mcimadamore@828 251
jjg@110 252 /** Instantiate undetermined type variable to the lub of all its lower bounds.
duke@1 253 * Throw a NoInstanceException if this not possible.
duke@1 254 */
duke@1 255 void minimizeInst(UndetVar that, Warner warn) throws NoInstanceException {
mcimadamore@828 256 List<Type> lobounds = Type.filter(that.lobounds, errorFilter);
duke@1 257 if (that.inst == null) {
mcimadamore@828 258 if (lobounds.isEmpty())
duke@1 259 that.inst = syms.botType;
mcimadamore@828 260 else if (lobounds.tail.isEmpty())
mcimadamore@828 261 that.inst = lobounds.head.isPrimitive() ? syms.errType : lobounds.head;
duke@1 262 else {
mcimadamore@828 263 that.inst = types.lub(lobounds);
mcimadamore@5 264 }
jjg@110 265 if (that.inst == null || that.inst.tag == ERROR)
duke@1 266 throw ambiguousNoInstanceException
duke@1 267 .setMessage("no.unique.minimal.instance.exists",
mcimadamore@828 268 that.qtype, lobounds);
duke@1 269 // VGJ: sort of inlined maximizeInst() below. Adding
duke@1 270 // bounds can cause lobounds that are above hibounds.
mcimadamore@828 271 List<Type> hibounds = Type.filter(that.hibounds, errorFilter);
mcimadamore@1087 272 Type hb = null;
mcimadamore@828 273 if (hibounds.isEmpty())
mcimadamore@1087 274 hb = syms.objectType;
mcimadamore@1087 275 else if (hibounds.tail.isEmpty())
mcimadamore@828 276 hb = hibounds.head;
mcimadamore@1087 277 else
mcimadamore@1087 278 hb = types.glb(hibounds);
duke@1 279 if (hb == null ||
mcimadamore@1087 280 hb.isErroneous())
mcimadamore@1087 281 throw ambiguousNoInstanceException
mcimadamore@1087 282 .setMessage("incompatible.upper.bounds",
mcimadamore@1087 283 that.qtype, hibounds);
duke@1 284 }
duke@1 285 }
duke@1 286
duke@1 287 /***************************************************************************
duke@1 288 * Exported Methods
duke@1 289 ***************************************************************************/
duke@1 290
duke@1 291 /** Try to instantiate expression type `that' to given type `to'.
duke@1 292 * If a maximal instantiation exists which makes this type
duke@1 293 * a subtype of type `to', return the instantiated type.
duke@1 294 * If no instantiation exists, or if several incomparable
duke@1 295 * best instantiations exist throw a NoInstanceException.
duke@1 296 */
duke@1 297 public Type instantiateExpr(ForAll that,
duke@1 298 Type to,
mcimadamore@299 299 Warner warn) throws InferenceException {
duke@1 300 List<Type> undetvars = Type.map(that.tvars, fromTypeVarFun);
duke@1 301 for (List<Type> l = undetvars; l.nonEmpty(); l = l.tail) {
mcimadamore@396 302 UndetVar uv = (UndetVar) l.head;
mcimadamore@396 303 TypeVar tv = (TypeVar)uv.qtype;
duke@1 304 ListBuffer<Type> hibounds = new ListBuffer<Type>();
mcimadamore@615 305 for (Type t : that.getConstraints(tv, ConstraintKind.EXTENDS)) {
mcimadamore@635 306 hibounds.append(types.subst(t, that.tvars, undetvars));
duke@1 307 }
mcimadamore@635 308
mcimadamore@396 309 List<Type> inst = that.getConstraints(tv, ConstraintKind.EQUAL);
mcimadamore@396 310 if (inst.nonEmpty() && inst.head.tag != BOT) {
mcimadamore@396 311 uv.inst = inst.head;
mcimadamore@396 312 }
mcimadamore@396 313 uv.hibounds = hibounds.toList();
duke@1 314 }
duke@1 315 Type qtype1 = types.subst(that.qtype, that.tvars, undetvars);
mcimadamore@753 316 if (!types.isSubtype(qtype1,
mcimadamore@753 317 qtype1.tag == UNDETVAR ? types.boxedTypeOrType(to) : to)) {
duke@1 318 throw unambiguousNoInstanceException
mcimadamore@689 319 .setMessage("infer.no.conforming.instance.exists",
duke@1 320 that.tvars, that.qtype, to);
duke@1 321 }
duke@1 322 for (List<Type> l = undetvars; l.nonEmpty(); l = l.tail)
duke@1 323 maximizeInst((UndetVar) l.head, warn);
duke@1 324 // System.out.println(" = " + qtype1.map(getInstFun));//DEBUG
duke@1 325
duke@1 326 // check bounds
duke@1 327 List<Type> targs = Type.map(undetvars, getInstFun);
mcimadamore@635 328 if (Type.containsAny(targs, that.tvars)) {
mcimadamore@635 329 //replace uninferred type-vars
mcimadamore@635 330 targs = types.subst(targs,
mcimadamore@635 331 that.tvars,
mcimadamore@635 332 instaniateAsUninferredVars(undetvars, that.tvars));
mcimadamore@635 333 }
mcimadamore@396 334 return chk.checkType(warn.pos(), that.inst(targs, types), to);
duke@1 335 }
mcimadamore@635 336 //where
mcimadamore@635 337 private List<Type> instaniateAsUninferredVars(List<Type> undetvars, List<Type> tvars) {
mcimadamore@635 338 ListBuffer<Type> new_targs = ListBuffer.lb();
mcimadamore@635 339 //step 1 - create syntethic captured vars
mcimadamore@635 340 for (Type t : undetvars) {
mcimadamore@635 341 UndetVar uv = (UndetVar)t;
mcimadamore@635 342 Type newArg = new CapturedType(t.tsym.name, t.tsym, uv.inst, syms.botType, null);
mcimadamore@635 343 new_targs = new_targs.append(newArg);
mcimadamore@635 344 }
mcimadamore@635 345 //step 2 - replace synthetic vars in their bounds
mcimadamore@635 346 for (Type t : new_targs.toList()) {
mcimadamore@635 347 CapturedType ct = (CapturedType)t;
mcimadamore@635 348 ct.bound = types.subst(ct.bound, tvars, new_targs.toList());
mcimadamore@635 349 WildcardType wt = new WildcardType(ct.bound, BoundKind.EXTENDS, syms.boundClass);
mcimadamore@635 350 ct.wildcard = wt;
mcimadamore@635 351 }
mcimadamore@635 352 return new_targs.toList();
mcimadamore@635 353 }
duke@1 354
duke@1 355 /** Instantiate method type `mt' by finding instantiations of
duke@1 356 * `tvars' so that method can be applied to `argtypes'.
duke@1 357 */
mcimadamore@547 358 public Type instantiateMethod(final Env<AttrContext> env,
mcimadamore@547 359 List<Type> tvars,
duke@1 360 MethodType mt,
mcimadamore@580 361 final Symbol msym,
mcimadamore@299 362 final List<Type> argtypes,
mcimadamore@299 363 final boolean allowBoxing,
mcimadamore@299 364 final boolean useVarargs,
mcimadamore@299 365 final Warner warn) throws InferenceException {
duke@1 366 //-System.err.println("instantiateMethod(" + tvars + ", " + mt + ", " + argtypes + ")"); //DEBUG
duke@1 367 List<Type> undetvars = Type.map(tvars, fromTypeVarFun);
duke@1 368 List<Type> formals = mt.argtypes;
mcimadamore@299 369 //need to capture exactly once - otherwise subsequent
mcimadamore@299 370 //applicability checks might fail
mcimadamore@299 371 final List<Type> capturedArgs = types.capture(argtypes);
mcimadamore@299 372 List<Type> actuals = capturedArgs;
mcimadamore@299 373 List<Type> actualsNoCapture = argtypes;
duke@1 374 // instantiate all polymorphic argument types and
duke@1 375 // set up lower bounds constraints for undetvars
duke@1 376 Type varargsFormal = useVarargs ? formals.last() : null;
mcimadamore@689 377 if (varargsFormal == null &&
mcimadamore@689 378 actuals.size() != formals.size()) {
mcimadamore@689 379 throw unambiguousNoInstanceException
mcimadamore@689 380 .setMessage("infer.arg.length.mismatch");
mcimadamore@689 381 }
mcimadamore@299 382 while (actuals.nonEmpty() && formals.head != varargsFormal) {
mcimadamore@299 383 Type formal = formals.head;
mcimadamore@299 384 Type actual = actuals.head.baseType();
mcimadamore@299 385 Type actualNoCapture = actualsNoCapture.head.baseType();
mcimadamore@299 386 if (actual.tag == FORALL)
mcimadamore@299 387 actual = instantiateArg((ForAll)actual, formal, tvars, warn);
mcimadamore@299 388 Type undetFormal = types.subst(formal, tvars, undetvars);
duke@1 389 boolean works = allowBoxing
mcimadamore@299 390 ? types.isConvertible(actual, undetFormal, warn)
mcimadamore@299 391 : types.isSubtypeUnchecked(actual, undetFormal, warn);
duke@1 392 if (!works) {
duke@1 393 throw unambiguousNoInstanceException
mcimadamore@689 394 .setMessage("infer.no.conforming.assignment.exists",
mcimadamore@299 395 tvars, actualNoCapture, formal);
duke@1 396 }
duke@1 397 formals = formals.tail;
mcimadamore@299 398 actuals = actuals.tail;
mcimadamore@299 399 actualsNoCapture = actualsNoCapture.tail;
duke@1 400 }
mcimadamore@689 401
mcimadamore@689 402 if (formals.head != varargsFormal) // not enough args
mcimadamore@689 403 throw unambiguousNoInstanceException.setMessage("infer.arg.length.mismatch");
duke@1 404
duke@1 405 // for varargs arguments as well
duke@1 406 if (useVarargs) {
mcimadamore@1006 407 Type elemType = types.elemtype(varargsFormal);
mcimadamore@299 408 Type elemUndet = types.subst(elemType, tvars, undetvars);
mcimadamore@299 409 while (actuals.nonEmpty()) {
mcimadamore@299 410 Type actual = actuals.head.baseType();
mcimadamore@299 411 Type actualNoCapture = actualsNoCapture.head.baseType();
mcimadamore@299 412 if (actual.tag == FORALL)
mcimadamore@299 413 actual = instantiateArg((ForAll)actual, elemType, tvars, warn);
mcimadamore@299 414 boolean works = types.isConvertible(actual, elemUndet, warn);
duke@1 415 if (!works) {
duke@1 416 throw unambiguousNoInstanceException
mcimadamore@689 417 .setMessage("infer.no.conforming.assignment.exists",
mcimadamore@299 418 tvars, actualNoCapture, elemType);
duke@1 419 }
mcimadamore@299 420 actuals = actuals.tail;
mcimadamore@299 421 actualsNoCapture = actualsNoCapture.tail;
duke@1 422 }
duke@1 423 }
duke@1 424
duke@1 425 // minimize as yet undetermined type variables
duke@1 426 for (Type t : undetvars)
duke@1 427 minimizeInst((UndetVar) t, warn);
duke@1 428
duke@1 429 /** Type variables instantiated to bottom */
duke@1 430 ListBuffer<Type> restvars = new ListBuffer<Type>();
duke@1 431
mcimadamore@396 432 /** Undet vars instantiated to bottom */
mcimadamore@396 433 final ListBuffer<Type> restundet = new ListBuffer<Type>();
mcimadamore@396 434
duke@1 435 /** Instantiated types or TypeVars if under-constrained */
duke@1 436 ListBuffer<Type> insttypes = new ListBuffer<Type>();
duke@1 437
duke@1 438 /** Instantiated types or UndetVars if under-constrained */
duke@1 439 ListBuffer<Type> undettypes = new ListBuffer<Type>();
duke@1 440
duke@1 441 for (Type t : undetvars) {
duke@1 442 UndetVar uv = (UndetVar)t;
duke@1 443 if (uv.inst.tag == BOT) {
duke@1 444 restvars.append(uv.qtype);
mcimadamore@396 445 restundet.append(uv);
duke@1 446 insttypes.append(uv.qtype);
duke@1 447 undettypes.append(uv);
duke@1 448 uv.inst = null;
duke@1 449 } else {
duke@1 450 insttypes.append(uv.inst);
duke@1 451 undettypes.append(uv.inst);
duke@1 452 }
duke@1 453 }
duke@1 454 checkWithinBounds(tvars, undettypes.toList(), warn);
duke@1 455
mcimadamore@299 456 mt = (MethodType)types.subst(mt, tvars, insttypes.toList());
mcimadamore@299 457
duke@1 458 if (!restvars.isEmpty()) {
duke@1 459 // if there are uninstantiated variables,
duke@1 460 // quantify result type with them
mcimadamore@299 461 final List<Type> inferredTypes = insttypes.toList();
mcimadamore@299 462 final List<Type> all_tvars = tvars; //this is the wrong tvars
mcimadamore@895 463 return new UninferredMethodType(mt, restvars.toList()) {
mcimadamore@299 464 @Override
mcimadamore@895 465 List<Type> getConstraints(TypeVar tv, ConstraintKind ck) {
mcimadamore@396 466 for (Type t : restundet.toList()) {
mcimadamore@396 467 UndetVar uv = (UndetVar)t;
mcimadamore@396 468 if (uv.qtype == tv) {
mcimadamore@396 469 switch (ck) {
mcimadamore@615 470 case EXTENDS: return uv.hibounds.appendList(types.subst(types.getBounds(tv), all_tvars, inferredTypes));
mcimadamore@396 471 case SUPER: return uv.lobounds;
mcimadamore@396 472 case EQUAL: return uv.inst != null ? List.of(uv.inst) : List.<Type>nil();
mcimadamore@396 473 }
mcimadamore@396 474 }
mcimadamore@396 475 }
mcimadamore@396 476 return List.nil();
mcimadamore@396 477 }
mcimadamore@396 478 @Override
mcimadamore@895 479 void check(List<Type> inferred, Types types) throws NoInstanceException {
mcimadamore@845 480 // check that actuals conform to inferred formals
mcimadamore@895 481 checkArgumentsAcceptable(env, capturedArgs, getParameterTypes(), allowBoxing, useVarargs, warn);
mcimadamore@396 482 // check that inferred bounds conform to their bounds
mcimadamore@396 483 checkWithinBounds(all_tvars,
mcimadamore@299 484 types.subst(inferredTypes, tvars, inferred), warn);
mcimadamore@547 485 if (useVarargs) {
mcimadamore@895 486 chk.checkVararg(env.tree.pos(), getParameterTypes(), msym);
mcimadamore@547 487 }
mcimadamore@299 488 }};
duke@1 489 }
mcimadamore@299 490 else {
mcimadamore@845 491 // check that actuals conform to inferred formals
mcimadamore@845 492 checkArgumentsAcceptable(env, capturedArgs, mt.getParameterTypes(), allowBoxing, useVarargs, warn);
mcimadamore@299 493 // return instantiated version of method type
mcimadamore@299 494 return mt;
mcimadamore@299 495 }
duke@1 496 }
duke@1 497 //where
duke@1 498
mcimadamore@895 499 /**
mcimadamore@895 500 * A delegated type representing a partially uninferred method type.
mcimadamore@895 501 * The return type of a partially uninferred method type is a ForAll
mcimadamore@895 502 * type - when the return type is instantiated (see Infer.instantiateExpr)
mcimadamore@895 503 * the underlying method type is also updated.
mcimadamore@895 504 */
mcimadamore@895 505 static abstract class UninferredMethodType extends DelegatedType {
mcimadamore@895 506
mcimadamore@895 507 final List<Type> tvars;
mcimadamore@895 508
mcimadamore@895 509 public UninferredMethodType(MethodType mtype, List<Type> tvars) {
mcimadamore@895 510 super(METHOD, new MethodType(mtype.argtypes, null, mtype.thrown, mtype.tsym));
mcimadamore@895 511 this.tvars = tvars;
mcimadamore@895 512 asMethodType().restype = new UninferredReturnType(tvars, mtype.restype);
mcimadamore@895 513 }
mcimadamore@895 514
mcimadamore@895 515 @Override
mcimadamore@895 516 public MethodType asMethodType() {
mcimadamore@895 517 return qtype.asMethodType();
mcimadamore@895 518 }
mcimadamore@895 519
mcimadamore@895 520 @Override
mcimadamore@895 521 public Type map(Mapping f) {
mcimadamore@895 522 return qtype.map(f);
mcimadamore@895 523 }
mcimadamore@895 524
mcimadamore@895 525 void instantiateReturnType(Type restype, List<Type> inferred, Types types) throws NoInstanceException {
mcimadamore@895 526 //update method type with newly inferred type-arguments
mcimadamore@895 527 qtype = new MethodType(types.subst(getParameterTypes(), tvars, inferred),
mcimadamore@895 528 restype,
mcimadamore@895 529 types.subst(UninferredMethodType.this.getThrownTypes(), tvars, inferred),
mcimadamore@895 530 UninferredMethodType.this.qtype.tsym);
mcimadamore@895 531 check(inferred, types);
mcimadamore@895 532 }
mcimadamore@895 533
mcimadamore@895 534 abstract void check(List<Type> inferred, Types types) throws NoInstanceException;
mcimadamore@895 535
mcimadamore@895 536 abstract List<Type> getConstraints(TypeVar tv, ConstraintKind ck);
mcimadamore@895 537
mcimadamore@895 538 class UninferredReturnType extends ForAll {
mcimadamore@895 539 public UninferredReturnType(List<Type> tvars, Type restype) {
mcimadamore@895 540 super(tvars, restype);
mcimadamore@895 541 }
mcimadamore@895 542 @Override
mcimadamore@895 543 public Type inst(List<Type> actuals, Types types) {
mcimadamore@895 544 Type newRestype = super.inst(actuals, types);
mcimadamore@895 545 instantiateReturnType(newRestype, actuals, types);
mcimadamore@895 546 return newRestype;
mcimadamore@895 547 }
mcimadamore@895 548 @Override
mcimadamore@895 549 public List<Type> getConstraints(TypeVar tv, ConstraintKind ck) {
mcimadamore@895 550 return UninferredMethodType.this.getConstraints(tv, ck);
mcimadamore@895 551 }
mcimadamore@895 552 }
mcimadamore@895 553 }
mcimadamore@895 554
mcimadamore@845 555 private void checkArgumentsAcceptable(Env<AttrContext> env, List<Type> actuals, List<Type> formals,
mcimadamore@845 556 boolean allowBoxing, boolean useVarargs, Warner warn) {
mcimadamore@845 557 try {
mcimadamore@845 558 rs.checkRawArgumentsAcceptable(env, actuals, formals,
mcimadamore@845 559 allowBoxing, useVarargs, warn);
mcimadamore@845 560 }
mcimadamore@845 561 catch (Resolve.InapplicableMethodException ex) {
mcimadamore@845 562 // inferred method is not applicable
mcimadamore@845 563 throw invalidInstanceException.setMessage(ex.getDiagnostic());
mcimadamore@845 564 }
mcimadamore@845 565 }
mcimadamore@845 566
mcimadamore@895 567 /** Try to instantiate argument type `that' to given type `to'.
mcimadamore@895 568 * If this fails, try to insantiate `that' to `to' where
mcimadamore@895 569 * every occurrence of a type variable in `tvars' is replaced
mcimadamore@895 570 * by an unknown type.
mcimadamore@895 571 */
mcimadamore@895 572 private Type instantiateArg(ForAll that,
mcimadamore@895 573 Type to,
mcimadamore@895 574 List<Type> tvars,
mcimadamore@895 575 Warner warn) throws InferenceException {
mcimadamore@895 576 List<Type> targs;
mcimadamore@895 577 try {
mcimadamore@895 578 return instantiateExpr(that, to, warn);
mcimadamore@895 579 } catch (NoInstanceException ex) {
mcimadamore@895 580 Type to1 = to;
mcimadamore@895 581 for (List<Type> l = tvars; l.nonEmpty(); l = l.tail)
mcimadamore@895 582 to1 = types.subst(to1, List.of(l.head), List.of(syms.unknownType));
mcimadamore@895 583 return instantiateExpr(that, to1, warn);
duke@1 584 }
mcimadamore@895 585 }
duke@1 586
duke@1 587 /** check that type parameters are within their bounds.
duke@1 588 */
mcimadamore@615 589 void checkWithinBounds(List<Type> tvars,
duke@1 590 List<Type> arguments,
duke@1 591 Warner warn)
mcimadamore@299 592 throws InvalidInstanceException {
duke@1 593 for (List<Type> tvs = tvars, args = arguments;
duke@1 594 tvs.nonEmpty();
duke@1 595 tvs = tvs.tail, args = args.tail) {
mcimadamore@828 596 if (args.head instanceof UndetVar ||
mcimadamore@828 597 tvars.head.getUpperBound().isErroneous()) continue;
duke@1 598 List<Type> bounds = types.subst(types.getBounds((TypeVar)tvs.head), tvars, arguments);
duke@1 599 if (!types.isSubtypeUnchecked(args.head, bounds, warn))
mcimadamore@299 600 throw invalidInstanceException
duke@1 601 .setMessage("inferred.do.not.conform.to.bounds",
mcimadamore@299 602 args.head, bounds);
duke@1 603 }
duke@1 604 }
mcimadamore@674 605
mcimadamore@674 606 /**
mcimadamore@674 607 * Compute a synthetic method type corresponding to the requested polymorphic
mcimadamore@820 608 * method signature. The target return type is computed from the immediately
mcimadamore@820 609 * enclosing scope surrounding the polymorphic-signature call.
mcimadamore@674 610 */
mcimadamore@674 611 Type instantiatePolymorphicSignatureInstance(Env<AttrContext> env, Type site,
mcimadamore@674 612 Name name,
mcimadamore@674 613 MethodSymbol spMethod, // sig. poly. method or null if none
mcimadamore@820 614 List<Type> argtypes) {
mcimadamore@674 615 final Type restype;
mcimadamore@716 616
mcimadamore@820 617 //The return type for a polymorphic signature call is computed from
mcimadamore@820 618 //the enclosing tree E, as follows: if E is a cast, then use the
mcimadamore@820 619 //target type of the cast expression as a return type; if E is an
mcimadamore@820 620 //expression statement, the return type is 'void' - otherwise the
mcimadamore@820 621 //return type is simply 'Object'. A correctness check ensures that
mcimadamore@820 622 //env.next refers to the lexically enclosing environment in which
mcimadamore@820 623 //the polymorphic signature call environment is nested.
mcimadamore@820 624
mcimadamore@820 625 switch (env.next.tree.getTag()) {
mcimadamore@820 626 case JCTree.TYPECAST:
mcimadamore@820 627 JCTypeCast castTree = (JCTypeCast)env.next.tree;
mcimadamore@820 628 restype = (TreeInfo.skipParens(castTree.expr) == env.tree) ?
mcimadamore@820 629 castTree.clazz.type :
mcimadamore@820 630 syms.objectType;
mcimadamore@820 631 break;
mcimadamore@820 632 case JCTree.EXEC:
mcimadamore@820 633 JCTree.JCExpressionStatement execTree =
mcimadamore@820 634 (JCTree.JCExpressionStatement)env.next.tree;
mcimadamore@820 635 restype = (TreeInfo.skipParens(execTree.expr) == env.tree) ?
mcimadamore@820 636 syms.voidType :
mcimadamore@820 637 syms.objectType;
mcimadamore@820 638 break;
mcimadamore@820 639 default:
mcimadamore@820 640 restype = syms.objectType;
mcimadamore@674 641 }
mcimadamore@674 642
mcimadamore@674 643 List<Type> paramtypes = Type.map(argtypes, implicitArgType);
mcimadamore@674 644 List<Type> exType = spMethod != null ?
mcimadamore@674 645 spMethod.getThrownTypes() :
mcimadamore@674 646 List.of(syms.throwableType); // make it throw all exceptions
mcimadamore@674 647
mcimadamore@674 648 MethodType mtype = new MethodType(paramtypes,
mcimadamore@674 649 restype,
mcimadamore@674 650 exType,
mcimadamore@674 651 syms.methodClass);
mcimadamore@674 652 return mtype;
mcimadamore@674 653 }
mcimadamore@674 654 //where
mcimadamore@674 655 Mapping implicitArgType = new Mapping ("implicitArgType") {
mcimadamore@674 656 public Type apply(Type t) {
mcimadamore@674 657 t = types.erasure(t);
mcimadamore@674 658 if (t.tag == BOT)
mcimadamore@674 659 // nulls type as the marker type Null (which has no instances)
mcimadamore@674 660 // infer as java.lang.Void for now
mcimadamore@674 661 t = types.boxedClass(syms.voidType).type;
mcimadamore@674 662 return t;
mcimadamore@674 663 }
mcimadamore@674 664 };
mcimadamore@895 665 }

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