1.1 --- a/src/share/classes/com/sun/tools/javac/comp/Infer.java Mon Jan 21 01:27:42 2013 -0500
1.2 +++ b/src/share/classes/com/sun/tools/javac/comp/Infer.java Mon Feb 04 18:08:53 2013 -0500
1.3 @@ -66,6 +66,9 @@
1.4 Log log;
1.5 JCDiagnostic.Factory diags;
1.6
1.7 + /** Should we inject return-type constraints earlier? */
1.8 + boolean allowEarlyReturnConstraints;
1.9 +
1.10 public static Infer instance(Context context) {
1.11 Infer instance = context.get(inferKey);
1.12 if (instance == null)
1.13 @@ -83,6 +86,7 @@
1.14 chk = Check.instance(context);
1.15 diags = JCDiagnostic.Factory.instance(context);
1.16 inferenceException = new InferenceException(diags);
1.17 + allowEarlyReturnConstraints = Source.instance(context).allowEarlyReturnConstraints();
1.18 }
1.19
1.20 /**
1.21 @@ -188,19 +192,6 @@
1.22 MethodType mtype,
1.23 Attr.ResultInfo resultInfo,
1.24 Warner warn) throws InferenceException {
1.25 - Type to = resultInfo.pt;
1.26 - if (to.hasTag(NONE) || resultInfo.checkContext.inferenceContext().free(resultInfo.pt)) {
1.27 - to = mtype.getReturnType().isPrimitiveOrVoid() ?
1.28 - mtype.getReturnType() : syms.objectType;
1.29 - }
1.30 - Type qtype1 = inferenceContext.asFree(mtype.getReturnType(), types);
1.31 - if (!types.isSubtype(qtype1,
1.32 - qtype1.hasTag(UNDETVAR) ? types.boxedTypeOrType(to) : to)) {
1.33 - throw inferenceException
1.34 - .setMessage("infer.no.conforming.instance.exists",
1.35 - inferenceContext.restvars(), mtype.getReturnType(), to);
1.36 - }
1.37 -
1.38 while (true) {
1.39 boolean stuck = true;
1.40 for (Type t : inferenceContext.undetvars) {
1.41 @@ -283,6 +274,11 @@
1.42 try {
1.43 methodCheck.argumentsAcceptable(env, deferredAttrContext, argtypes, mt.getParameterTypes(), warn);
1.44
1.45 + if (resultInfo != null && allowEarlyReturnConstraints &&
1.46 + !warn.hasNonSilentLint(Lint.LintCategory.UNCHECKED)) {
1.47 + generateReturnConstraints(mt, inferenceContext, resultInfo);
1.48 + }
1.49 +
1.50 deferredAttrContext.complete();
1.51
1.52 // minimize as yet undetermined type variables
1.53 @@ -298,6 +294,9 @@
1.54
1.55 if (!restvars.isEmpty()) {
1.56 if (resultInfo != null && !warn.hasNonSilentLint(Lint.LintCategory.UNCHECKED)) {
1.57 + if (!allowEarlyReturnConstraints) {
1.58 + generateReturnConstraints(mt, inferenceContext, resultInfo);
1.59 + }
1.60 instantiateUninferred(env.tree.pos(), inferenceContext, mt, resultInfo, warn);
1.61 checkWithinBounds(inferenceContext, warn);
1.62 mt = (MethodType)inferenceContext.asInstType(mt, types);
1.63 @@ -313,6 +312,25 @@
1.64 inferenceContext.notifyChange(types);
1.65 }
1.66 }
1.67 + //where
1.68 + void generateReturnConstraints(Type mt, InferenceContext inferenceContext, Attr.ResultInfo resultInfo) {
1.69 + if (resultInfo != null) {
1.70 + Type to = resultInfo.pt;
1.71 + if (to.hasTag(NONE) || resultInfo.checkContext.inferenceContext().free(resultInfo.pt)) {
1.72 + to = mt.getReturnType().isPrimitiveOrVoid() ?
1.73 + mt.getReturnType() : syms.objectType;
1.74 + }
1.75 + Type qtype1 = inferenceContext.asFree(mt.getReturnType(), types);
1.76 + Warner retWarn = new Warner();
1.77 + if (!resultInfo.checkContext.compatible(qtype1, qtype1.hasTag(UNDETVAR) ? types.boxedTypeOrType(to) : to, retWarn) ||
1.78 + //unchecked conversion is not allowed
1.79 + retWarn.hasLint(Lint.LintCategory.UNCHECKED)) {
1.80 + throw inferenceException
1.81 + .setMessage("infer.no.conforming.instance.exists",
1.82 + inferenceContext.restvars(), mt.getReturnType(), to);
1.83 + }
1.84 + }
1.85 + }
1.86
1.87 /** check that type parameters are within their bounds.
1.88 */
1.89 @@ -461,52 +479,40 @@
1.90 Type formalInterface = funcInterface.tsym.type;
1.91 InferenceContext funcInterfaceContext =
1.92 new InferenceContext(funcInterface.tsym.type.getTypeArguments(), this, false);
1.93 - if (paramTypes != null) {
1.94 - //get constraints from explicit params (this is done by
1.95 - //checking that explicit param types are equal to the ones
1.96 - //in the functional interface descriptors)
1.97 - List<Type> descParameterTypes = types.findDescriptorType(formalInterface).getParameterTypes();
1.98 - if (descParameterTypes.size() != paramTypes.size()) {
1.99 - checkContext.report(pos, diags.fragment("incompatible.arg.types.in.lambda"));
1.100 + Assert.check(paramTypes != null);
1.101 + //get constraints from explicit params (this is done by
1.102 + //checking that explicit param types are equal to the ones
1.103 + //in the functional interface descriptors)
1.104 + List<Type> descParameterTypes = types.findDescriptorType(formalInterface).getParameterTypes();
1.105 + if (descParameterTypes.size() != paramTypes.size()) {
1.106 + checkContext.report(pos, diags.fragment("incompatible.arg.types.in.lambda"));
1.107 + return types.createErrorType(funcInterface);
1.108 + }
1.109 + for (Type p : descParameterTypes) {
1.110 + if (!types.isSameType(funcInterfaceContext.asFree(p, types), paramTypes.head)) {
1.111 + checkContext.report(pos, diags.fragment("no.suitable.functional.intf.inst", funcInterface));
1.112 return types.createErrorType(funcInterface);
1.113 }
1.114 - for (Type p : descParameterTypes) {
1.115 - if (!types.isSameType(funcInterfaceContext.asFree(p, types), paramTypes.head)) {
1.116 - checkContext.report(pos, diags.fragment("no.suitable.functional.intf.inst", funcInterface));
1.117 - return types.createErrorType(funcInterface);
1.118 - }
1.119 - paramTypes = paramTypes.tail;
1.120 + paramTypes = paramTypes.tail;
1.121 + }
1.122 + List<Type> actualTypeargs = funcInterface.getTypeArguments();
1.123 + for (Type t : funcInterfaceContext.undetvars) {
1.124 + UndetVar uv = (UndetVar)t;
1.125 + minimizeInst(uv, types.noWarnings);
1.126 + if (uv.inst == null &&
1.127 + Type.filter(uv.getBounds(InferenceBound.UPPER), boundFilter).nonEmpty()) {
1.128 + maximizeInst(uv, types.noWarnings);
1.129 }
1.130 - for (Type t : funcInterfaceContext.undetvars) {
1.131 - UndetVar uv = (UndetVar)t;
1.132 - minimizeInst(uv, types.noWarnings);
1.133 - if (uv.inst == null &&
1.134 - Type.filter(uv.getBounds(InferenceBound.UPPER), boundFilter).nonEmpty()) {
1.135 - maximizeInst(uv, types.noWarnings);
1.136 - }
1.137 - }
1.138 -
1.139 - formalInterface = funcInterfaceContext.asInstType(formalInterface, types);
1.140 - }
1.141 - ListBuffer<Type> typeargs = ListBuffer.lb();
1.142 - List<Type> actualTypeargs = funcInterface.getTypeArguments();
1.143 - //for remaining uninferred type-vars in the functional interface type,
1.144 - //simply replace the wildcards with its bound
1.145 - for (Type t : formalInterface.getTypeArguments()) {
1.146 - if (actualTypeargs.head.hasTag(WILDCARD)) {
1.147 - WildcardType wt = (WildcardType)actualTypeargs.head;
1.148 - typeargs.append(wt.type);
1.149 - } else {
1.150 - typeargs.append(actualTypeargs.head);
1.151 + if (uv.inst == null) {
1.152 + uv.inst = actualTypeargs.head;
1.153 }
1.154 actualTypeargs = actualTypeargs.tail;
1.155 }
1.156 - Type owntype = types.subst(formalInterface, funcInterfaceContext.inferenceVars(), typeargs.toList());
1.157 + Type owntype = funcInterfaceContext.asInstType(formalInterface, types);
1.158 if (!chk.checkValidGenericType(owntype)) {
1.159 //if the inferred functional interface type is not well-formed,
1.160 //or if it's not a subtype of the original target, issue an error
1.161 checkContext.report(pos, diags.fragment("no.suitable.functional.intf.inst", funcInterface));
1.162 - return types.createErrorType(funcInterface);
1.163 }
1.164 return owntype;
1.165 }
