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6943278: spurious error message for inference and type-variable with erroneous bound

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Type-inference should ignore erroneous bounds

Reviewed-by: jjg
This commit is contained in:
Maurizio Cimadamore 2011-01-24 15:44:15 +00:00
parent a13fa350f1
commit df54c56a04
5 changed files with 60 additions and 19 deletions
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10
langtools/src/share/classes/com/sun/tools/javac/code/Type.java
View file

@ -365,6 +365,16 @@ public class Type implements PrimitiveType {
return false;
}
public static List<Type> filter(List<Type> ts, Filter<Type> tf) {
ListBuffer<Type> buf = ListBuffer.lb();
for (Type t : ts) {
if (tf.accepts(t)) {
buf.append(t);
}
}
return buf.toList();
}
public boolean isSuperBound() { return false; }
public boolean isExtendsBound() { return false; }
public boolean isUnbound() { return false; }

9
langtools/src/share/classes/com/sun/tools/javac/comp/Check.java
View file

@ -800,7 +800,8 @@ public class Check {
Type actual = types.subst(args.head,
type.tsym.type.getTypeArguments(),
tvars_buf.toList());
if (!checkExtends(actual, (TypeVar)tvars.head)) {
if (!checkExtends(actual, (TypeVar)tvars.head) &&
!tvars.head.getUpperBound().isErroneous()) {
return args.head;
}
args = args.tail;
@ -808,11 +809,15 @@ public class Check {
}
args = type.getTypeArguments();
tvars = tvars_buf.toList();
for (Type arg : types.capture(type).getTypeArguments()) {
if (arg.tag == TYPEVAR && arg.getUpperBound().isErroneous()) {
if (arg.tag == TYPEVAR &&
arg.getUpperBound().isErroneous() &&
!tvars.head.getUpperBound().isErroneous()) {
return args.head;
}
tvars = tvars.tail;
}
return null;

45
langtools/src/share/classes/com/sun/tools/javac/comp/Infer.java
View file

@ -205,19 +205,20 @@ public class Infer {
* Throw a NoInstanceException if this not possible.
*/
void maximizeInst(UndetVar that, Warner warn) throws NoInstanceException {
List<Type> hibounds = Type.filter(that.hibounds, errorFilter);
if (that.inst == null) {
if (that.hibounds.isEmpty())
if (hibounds.isEmpty())
that.inst = syms.objectType;
else if (that.hibounds.tail.isEmpty())
that.inst = that.hibounds.head;
else if (hibounds.tail.isEmpty())
that.inst = hibounds.head;
else
that.inst = types.glb(that.hibounds);
that.inst = types.glb(hibounds);
}
if (that.inst == null ||
that.inst.isErroneous())
throw ambiguousNoInstanceException
.setMessage("no.unique.maximal.instance.exists",
that.qtype, that.hibounds);
that.qtype, hibounds);
}
//where
private boolean isSubClass(Type t, final List<Type> ts) {
@ -241,37 +242,46 @@ public class Infer {
return true;
}
private Filter<Type> errorFilter = new Filter<Type>() {
@Override
public boolean accepts(Type t) {
return !t.isErroneous();
}
};
/** Instantiate undetermined type variable to the lub of all its lower bounds.
* Throw a NoInstanceException if this not possible.
*/
void minimizeInst(UndetVar that, Warner warn) throws NoInstanceException {
List<Type> lobounds = Type.filter(that.lobounds, errorFilter);
if (that.inst == null) {
if (that.lobounds.isEmpty())
if (lobounds.isEmpty())
that.inst = syms.botType;
else if (that.lobounds.tail.isEmpty())
that.inst = that.lobounds.head.isPrimitive() ? syms.errType : that.lobounds.head;
else if (lobounds.tail.isEmpty())
that.inst = lobounds.head.isPrimitive() ? syms.errType : lobounds.head;
else {
that.inst = types.lub(that.lobounds);
that.inst = types.lub(lobounds);
}
if (that.inst == null || that.inst.tag == ERROR)
throw ambiguousNoInstanceException
.setMessage("no.unique.minimal.instance.exists",
that.qtype, that.lobounds);
that.qtype, lobounds);
// VGJ: sort of inlined maximizeInst() below. Adding
// bounds can cause lobounds that are above hibounds.
if (that.hibounds.isEmpty())
List<Type> hibounds = Type.filter(that.hibounds, errorFilter);
if (hibounds.isEmpty())
return;
Type hb = null;
if (that.hibounds.tail.isEmpty())
hb = that.hibounds.head;
else for (List<Type> bs = that.hibounds;
if (hibounds.tail.isEmpty())
hb = hibounds.head;
else for (List<Type> bs = hibounds;
bs.nonEmpty() && hb == null;
bs = bs.tail) {
if (isSubClass(bs.head, that.hibounds))
if (isSubClass(bs.head, hibounds))
hb = types.fromUnknownFun.apply(bs.head);
}
if (hb == null ||
!types.isSubtypeUnchecked(hb, that.hibounds, warn) ||
!types.isSubtypeUnchecked(hb, hibounds, warn) ||
!types.isSubtypeUnchecked(that.inst, hb, warn))
throw ambiguousNoInstanceException;
}
@ -528,7 +538,8 @@ public class Infer {
for (List<Type> tvs = tvars, args = arguments;
tvs.nonEmpty();
tvs = tvs.tail, args = args.tail) {
if (args.head instanceof UndetVar) continue;
if (args.head instanceof UndetVar ||
tvars.head.getUpperBound().isErroneous()) continue;
List<Type> bounds = types.subst(types.getBounds((TypeVar)tvs.head), tvars, arguments);
if (!types.isSubtypeUnchecked(args.head, bounds, warn))
throw invalidInstanceException

12
langtools/test/tools/javac/generics/inference/6943278/T6943278.java Normal file
View file

@ -0,0 +1,12 @@
/**
* @test /nodynamiccopyright/
* @bug 6943278
* @summary spurious error message for inference and type-variable with erroneous bound
* @compile/fail/ref=T6943278.out -XDrawDiagnostics -Xlint:unchecked T6943278.java
*/
class T6943278<X extends Number & NonExistentInterface> {
<X> T6943278<X> m() { return null;}
<X extends Number & NonExistentInterface> T6943278<X> m(X x) { return null;}
T6943278<?> f1 = m();
T6943278<?> f2 = m("");
}

3
langtools/test/tools/javac/generics/inference/6943278/T6943278.out Normal file
View file

@ -0,0 +1,3 @@
T6943278.java:7:35: compiler.err.cant.resolve: kindname.class, NonExistentInterface, ,
T6943278.java:9:25: compiler.err.cant.resolve.location: kindname.class, NonExistentInterface, , , kindname.class, T6943278<X>
2 errors