8019824: very long error messages on inference error
Summary: Inference error messages shows several spurious captured variables generated during an inference loop
Reviewed-by: jjg, vromero
--- a/langtools/src/share/classes/com/sun/tools/javac/code/Type.java Fri Jul 05 11:04:22 2013 +0100
+++ b/langtools/src/share/classes/com/sun/tools/javac/code/Type.java Fri Jul 05 11:05:02 2013 +0100
@@ -1514,9 +1514,14 @@
return buf.toList();
}
+ /** internal method used to override an undetvar bounds */
+ public void setBounds(InferenceBound ib, List<Type> newBounds) {
+ bounds.put(ib, newBounds);
+ }
+
/** add a bound of a given kind - this might trigger listener notification */
public void addBound(InferenceBound ib, Type bound, Types types) {
- Type bound2 = toTypeVarMap.apply(bound);
+ Type bound2 = boundMap.apply(bound);
List<Type> prevBounds = bounds.get(ib);
for (Type b : prevBounds) {
//check for redundancy - use strict version of isSameType on tvars
@@ -1527,12 +1532,12 @@
notifyChange(EnumSet.of(ib));
}
//where
- Type.Mapping toTypeVarMap = new Mapping("toTypeVarMap") {
+ Type.Mapping boundMap = new Mapping("boundMap") {
@Override
public Type apply(Type t) {
if (t.hasTag(UNDETVAR)) {
UndetVar uv = (UndetVar)t;
- return uv.qtype;
+ return uv.inst != null ? uv.inst : uv.qtype;
} else {
return t.map(this);
}
--- a/langtools/src/share/classes/com/sun/tools/javac/comp/Infer.java Fri Jul 05 11:04:22 2013 +0100
+++ b/langtools/src/share/classes/com/sun/tools/javac/comp/Infer.java Fri Jul 05 11:05:02 2013 +0100
@@ -418,6 +418,7 @@
void checkWithinBounds(InferenceContext inferenceContext,
Warner warn) throws InferenceException {
MultiUndetVarListener mlistener = new MultiUndetVarListener(inferenceContext.undetvars);
+ List<Type> saved_undet = inferenceContext.save();
try {
while (true) {
mlistener.reset();
@@ -443,6 +444,9 @@
}
finally {
mlistener.detach();
+ if (mlistener.rounds == MAX_INCORPORATION_STEPS) {
+ inferenceContext.rollback(saved_undet);
+ }
}
}
//where
@@ -645,7 +649,7 @@
UndetVar uv2 = (UndetVar)inferenceContext.asFree(b);
//alpha <: beta
//0. set beta :> alpha
- uv2.addBound(InferenceBound.LOWER, uv.qtype, infer.types);
+ uv2.addBound(InferenceBound.LOWER, uv, infer.types);
//1. copy alpha's lower to beta's
for (Type l : uv.getBounds(InferenceBound.LOWER)) {
uv2.addBound(InferenceBound.LOWER, inferenceContext.asInstType(l), infer.types);
@@ -670,7 +674,7 @@
UndetVar uv2 = (UndetVar)inferenceContext.asFree(b);
//alpha :> beta
//0. set beta <: alpha
- uv2.addBound(InferenceBound.UPPER, uv.qtype, infer.types);
+ uv2.addBound(InferenceBound.UPPER, uv, infer.types);
//1. copy alpha's upper to beta's
for (Type u : uv.getBounds(InferenceBound.UPPER)) {
uv2.addBound(InferenceBound.UPPER, inferenceContext.asInstType(u), infer.types);
@@ -695,7 +699,7 @@
UndetVar uv2 = (UndetVar)inferenceContext.asFree(b);
//alpha == beta
//0. set beta == alpha
- uv2.addBound(InferenceBound.EQ, uv.qtype, infer.types);
+ uv2.addBound(InferenceBound.EQ, uv, infer.types);
//1. copy all alpha's bounds to beta's
for (InferenceBound ib : InferenceBound.values()) {
for (Type b2 : uv.getBounds(ib)) {
@@ -1090,7 +1094,7 @@
while (!sstrategy.done()) {
InferenceGraph.Node nodeToSolve = sstrategy.pickNode(inferenceGraph);
List<Type> varsToSolve = List.from(nodeToSolve.data);
- inferenceContext.save();
+ List<Type> saved_undet = inferenceContext.save();
try {
//repeat until all variables are solved
outer: while (Type.containsAny(inferenceContext.restvars(), varsToSolve)) {
@@ -1107,7 +1111,7 @@
}
catch (InferenceException ex) {
//did we fail because of interdependent ivars?
- inferenceContext.rollback();
+ inferenceContext.rollback(saved_undet);
instantiateAsUninferredVars(varsToSolve, inferenceContext);
checkWithinBounds(inferenceContext, warn);
}
@@ -1502,7 +1506,7 @@
/**
* Save the state of this inference context
*/
- void save() {
+ List<Type> save() {
ListBuffer<Type> buf = ListBuffer.lb();
for (Type t : undetvars) {
UndetVar uv = (UndetVar)t;
@@ -1515,16 +1519,24 @@
uv2.inst = uv.inst;
buf.add(uv2);
}
- saved_undet = buf.toList();
+ return buf.toList();
}
/**
* Restore the state of this inference context to the previous known checkpoint
*/
- void rollback() {
- Assert.check(saved_undet != null && saved_undet.length() == undetvars.length());
- undetvars = saved_undet;
- saved_undet = null;
+ void rollback(List<Type> saved_undet) {
+ Assert.check(saved_undet != null && saved_undet.length() == undetvars.length());
+ //restore bounds (note: we need to preserve the old instances)
+ for (Type t : undetvars) {
+ UndetVar uv = (UndetVar)t;
+ UndetVar uv_saved = (UndetVar)saved_undet.head;
+ for (InferenceBound ib : InferenceBound.values()) {
+ uv.setBounds(ib, uv_saved.getBounds(ib));
+ }
+ uv.inst = uv_saved.inst;
+ saved_undet = saved_undet.tail;
+ }
}
/**
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/8019824/T8019824.java Fri Jul 05 11:05:02 2013 +0100
@@ -0,0 +1,15 @@
+/**
+ * @test /nodynamiccopyright/
+ * @bug 8019824
+ * @summary very long error messages on inference error
+ * @compile/fail/ref=T8019824.out -XDrawDiagnostics T8019824.java
+ */
+class T8019824 {
+ void test(Class<? extends Foo<?, ?>> cls) {
+ Foo<?, ?> foo = make(cls);
+ }
+
+ <A, B, C extends Foo<A, B>> Foo<A, B> make(Class<C> cls) { return null; }
+
+ interface Foo<A, B> {}
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/generics/inference/8019824/T8019824.out Fri Jul 05 11:05:02 2013 +0100
@@ -0,0 +1,2 @@
+T8019824.java:9:25: compiler.err.cant.apply.symbol: kindname.method, make, java.lang.Class<C>, java.lang.Class<compiler.misc.type.captureof: 1, ? extends T8019824.Foo<?,?>>, kindname.class, T8019824, (compiler.misc.incompatible.eq.upper.bounds: C, compiler.misc.type.captureof: 1, ? extends T8019824.Foo<?,?>, T8019824.Foo<java.lang.Object,B>)
+1 error