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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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package com.sun.tools.javac.comp;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.code.Symtab;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Type.ArrayType;
import com.sun.tools.javac.code.Type.ErrorType;
import com.sun.tools.javac.code.TypeTag;
import com.sun.tools.javac.code.Types;
import com.sun.tools.javac.comp.Attr.ResultInfo;
import com.sun.tools.javac.comp.DeferredAttr.AttrMode;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCErroneous;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCLambda;
import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
import com.sun.tools.javac.tree.JCTree.JCReturn;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.tree.JCTree.Tag;
import com.sun.tools.javac.tree.TreeInfo;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.TreeTranslator;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.JCDiagnostic;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Names;
This is an error recovery addon for Attr. Currently, it recovers
method invocations with lambdas, that require type inference.
This is NOT part of any supported API.
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.
/** This is an error recovery addon for Attr. Currently, it recovers
* method invocations with lambdas, that require type inference.
*
* <p><b>This is NOT part of any supported API.
* 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 AttrRecover {
protected static final Context.Key<AttrRecover> attrRepairKey = new Context.Key<>();
final Attr attr;
final DeferredAttr deferredAttr;
final Names names;
final TreeMaker make;
final Symtab syms;
final Types types;
public static AttrRecover instance(Context context) {
AttrRecover instance = context.get(attrRepairKey);
if (instance == null)
instance = new AttrRecover(context);
return instance;
}
protected AttrRecover(Context context) {
context.put(attrRepairKey, this);
attr = Attr.instance(context);
deferredAttr = DeferredAttr.instance(context);
names = Names.instance(context);
make = TreeMaker.instance(context);
syms = Symtab.instance(context);
types = Types.instance(context);
}
private final ListBuffer<RecoverTodo> recoveryTodo = new ListBuffer<>();
public void doRecovery() {
while (recoveryTodo.nonEmpty()) {
RecoverTodo todo = recoveryTodo.remove();
ListBuffer<Runnable> rollback = new ListBuffer<>();
boolean repaired = false;
RECOVER: if (todo.env.tree.hasTag(Tag.APPLY)) {
JCMethodInvocation mit = (JCMethodInvocation) todo.env.tree;
boolean vararg = (todo.candSym.flags() & Flags.VARARGS) != 0;
if (!vararg &&
mit.args.length() > todo.candSym.type.getParameterTypes().length()) {
break RECOVER; //too many actual parameters, skip
}
List<JCExpression> args = mit.args;
List<Type> formals = todo.candSym.type.getParameterTypes();
while (args.nonEmpty() && formals.nonEmpty()) {
JCExpression arg = args.head;
Type formal = formals.tail.nonEmpty() || !vararg
? formals.head : ((ArrayType) formals.head).elemtype;
if (arg.hasTag(JCTree.Tag.LAMBDA)) {
final JCTree.JCLambda lambda = (JCLambda) arg;
if (lambda.paramKind == JCLambda.ParameterKind.IMPLICIT) {
for (JCVariableDecl var : lambda.params) {
var.vartype = null; //reset type
}
}
if (types.isFunctionalInterface(formal)) {
Type functionalType = types.findDescriptorType(formal);
boolean voidCompatible = functionalType.getReturnType().hasTag(TypeTag.VOID);
lambda.body = new TreeTranslator() {
@Override
public void visitReturn(JCReturn tree) {
result = tree;
if (voidCompatible) {
if (tree.expr != null) {
JCErroneous err = make.Erroneous(List.of(tree));
result = err;
rollback.append(() -> {
lambda.body = new TreeTranslator() {
@SuppressWarnings("unchecked")
public <T extends JCTree> T translate(T t) {
if (t == err) return (T) tree;
else return super.translate(t);
}
}.translate(lambda.body);
});
}
} else {
if (tree.expr == null) {
tree.expr = make.Erroneous().setType(syms.errType);
rollback.append(() -> {
tree.expr = null;
});
}
}
}
@Override
public void visitLambda(JCLambda tree) {
//do not touch nested lambdas
}
@Override
public void visitClassDef(JCClassDecl tree) {
//do not touch nested classes
}
}.translate(lambda.body);
if (!voidCompatible) {
JCReturn ret = make.Return(make.Erroneous().setType(syms.errType));
((JCBlock) lambda.body).stats = ((JCBlock) lambda.body).stats.append(ret);
rollback.append(() -> {
((JCBlock) lambda.body).stats = List.filter(((JCBlock) lambda.body).stats, ret);
});
}
}
repaired = true;
}
args = args.tail;
if (formals.tail.nonEmpty() || !vararg) {
formals = formals.tail;
}
}
List<JCExpression> prevArgs = mit.args;
while (formals.nonEmpty()) {
mit.args = mit.args.append(make.Erroneous().setType(syms.errType));
formals = formals.tail;
repaired = true;
}
rollback.append(() -> {
mit.args = prevArgs;
});
}
Type owntype;
if (repaired) {
List<JCExpression> args = TreeInfo.args(todo.env.tree);
List<Type> pats = todo.resultInfo.pt.getParameterTypes();
while (pats.length() < args.length()) {
pats = pats.append(syms.errType);
}
owntype = attr.checkMethod(todo.site, todo.candSym,
attr.new ResultInfo(todo.resultInfo.pkind, todo.resultInfo.pt.getReturnType(), todo.resultInfo.checkContext, todo.resultInfo.checkMode),
todo.env, args, pats,
todo.resultInfo.pt.getTypeArguments());
rollback.stream().forEach(Runnable::run);
} else {
owntype = basicMethodInvocationRecovery(todo.tree, todo.site, todo.errSym, todo.env, todo.resultInfo);
}
todo.tree.type = owntype;
}
}
Type recoverMethodInvocation(JCTree tree,
Type site,
Symbol sym,
Env<AttrContext> env,
ResultInfo resultInfo) {
if ((sym.flags_field & Flags.RECOVERABLE) != 0 && env.info.attributionMode.recover()) {
recoveryTodo.append(new RecoverTodo(tree, site, sym, ((RecoveryErrorType) sym.type).candidateSymbol, attr.copyEnv(env), resultInfo));
return syms.errType;
} else {
return basicMethodInvocationRecovery(tree, site, sym, env, resultInfo);
}
}
private Type basicMethodInvocationRecovery(JCTree tree,
Type site,
Symbol sym,
Env<AttrContext> env,
ResultInfo resultInfo) {
Type pt = resultInfo.pt.map(deferredAttr.new RecoveryDeferredTypeMap(AttrMode.SPECULATIVE, sym, env.info.pendingResolutionPhase));
Type owntype = attr.checkIdInternal(tree, site, sym, pt, env, resultInfo);
resultInfo.pt.map(deferredAttr.new RecoveryDeferredTypeMap(AttrMode.CHECK, sym, env.info.pendingResolutionPhase));
return owntype;
}
void wrongMethodSymbolCandidate(TypeSymbol errSymbol, Symbol candSym, JCDiagnostic diag) {
List<JCDiagnostic> diags = List.of(diag);
boolean recoverable = false;
while (!recoverable && diags.nonEmpty()) {
JCDiagnostic d = diags.head;
diags = diags.tail;
switch (d.getCode()) {
case "compiler.misc.missing.ret.val":
case "compiler.misc.unexpected.ret.val":
case "compiler.misc.infer.arg.length.mismatch":
case "compiler.misc.arg.length.mismatch":
errSymbol.type = new RecoveryErrorType((Type.ErrorType) errSymbol.type, candSym);
errSymbol.flags_field |= Flags.RECOVERABLE;
return ;
default:
break;
}
for (Object a : d.getArgs()) {
if (a instanceof JCDiagnostic) {
diags = diags.prepend((JCDiagnostic) a);
}
}
}
}
private static class RecoveryErrorType extends ErrorType {
public final Symbol candidateSymbol;
public RecoveryErrorType(ErrorType original, Symbol candidateSymbol) {
super(original.getOriginalType(), original.tsym);
this.candidateSymbol = candidateSymbol;
}
}
private static class RecoverTodo {
public final JCTree tree;
public final Type site;
public final Symbol errSym;
public final Symbol candSym;
public final Env<AttrContext> env;
public final ResultInfo resultInfo;
public RecoverTodo(JCTree tree, Type site, Symbol errSym, Symbol candSym,
Env<AttrContext> env, Attr.ResultInfo resultInfo) {
this.tree = tree;
this.site = site;
this.errSym = errSym;
this.candSym = candSym;
this.env = env;
this.resultInfo = resultInfo;
}
}
}