private static boolean resolveSubstituteConstraints(
Scope scope,
TypeVariableBinding[] typeVariables,
InferenceContext inferenceContext,
boolean considerEXTENDSConstraints) {
TypeBinding[] substitutes = inferenceContext.substitutes;
int varLength = typeVariables.length;
// check Tj=U constraints
nextTypeParameter:
for (int i = 0; i < varLength; i++) {
TypeVariableBinding current = typeVariables[i];
TypeBinding substitute = substitutes[i];
if (substitute != null) continue nextTypeParameter; // already inferred previously
TypeBinding[] equalSubstitutes =
inferenceContext.getSubstitutes(current, TypeConstants.CONSTRAINT_EQUAL);
if (equalSubstitutes != null) {
nextConstraint:
for (int j = 0, equalLength = equalSubstitutes.length; j < equalLength; j++) {
TypeBinding equalSubstitute = equalSubstitutes[j];
if (equalSubstitute == null) continue nextConstraint;
if (equalSubstitute == current) {
// try to find a better different match if any in subsequent equal candidates
for (int k = j + 1; k < equalLength; k++) {
equalSubstitute = equalSubstitutes[k];
if (equalSubstitute != current && equalSubstitute != null) {
substitutes[i] = equalSubstitute;
continue nextTypeParameter;
}
}
substitutes[i] = current;
continue nextTypeParameter;
}
// if (equalSubstitute.isTypeVariable()) {
// TypeVariableBinding variable = (TypeVariableBinding) equalSubstitute;
// // substituted by a variable of the same method, ignore
// if (variable.rank < varLength && typeVariables[variable.rank] == variable) {
// // TODO (philippe) rewrite all other constraints to use current instead.
// continue nextConstraint;
// }
// }
substitutes[i] = equalSubstitute;
continue nextTypeParameter; // pick first match, applicability check will rule out invalid
// scenario where others were present
}
}
}
if (inferenceContext.hasUnresolvedTypeArgument()) {
// check Tj>:U constraints
nextTypeParameter:
for (int i = 0; i < varLength; i++) {
TypeVariableBinding current = typeVariables[i];
TypeBinding substitute = substitutes[i];
if (substitute != null) continue nextTypeParameter; // already inferred previously
TypeBinding[] bounds =
inferenceContext.getSubstitutes(current, TypeConstants.CONSTRAINT_SUPER);
if (bounds == null) continue nextTypeParameter;
TypeBinding mostSpecificSubstitute = scope.lowerUpperBound(bounds);
if (mostSpecificSubstitute == null) {
return false; // incompatible
}
if (mostSpecificSubstitute != TypeBinding.VOID) {
substitutes[i] = mostSpecificSubstitute;
}
}
}
if (considerEXTENDSConstraints && inferenceContext.hasUnresolvedTypeArgument()) {
// check Tj<:U constraints
nextTypeParameter:
for (int i = 0; i < varLength; i++) {
TypeVariableBinding current = typeVariables[i];
TypeBinding substitute = substitutes[i];
if (substitute != null) continue nextTypeParameter; // already inferred previously
TypeBinding[] bounds =
inferenceContext.getSubstitutes(current, TypeConstants.CONSTRAINT_EXTENDS);
if (bounds == null) continue nextTypeParameter;
TypeBinding[] glb = Scope.greaterLowerBound(bounds);
TypeBinding mostSpecificSubstitute = null;
if (glb != null) mostSpecificSubstitute = glb[0]; // TODO (philippe) need to improve
// TypeBinding mostSpecificSubstitute = scope.greaterLowerBound(bounds);
if (mostSpecificSubstitute != null) {
substitutes[i] = mostSpecificSubstitute;
}
}
}
return true;
}
private static boolean resolveSubstituteConstraints(
Scope scope,
TypeVariableBinding[] typeVariables,
InferenceContext inferenceContext,
boolean considerEXTENDSConstraints) {
TypeBinding[] substitutes = inferenceContext.substitutes;
int varLength = typeVariables.length;
// check Tj=U constraints
nextTypeParameter:
for (int i = 0; i < varLength; i++) {
TypeVariableBinding current = typeVariables[i];
TypeBinding substitute = substitutes[i];
if (substitute != null) continue nextTypeParameter; // already inferred previously
TypeBinding[] equalSubstitutes =
inferenceContext.getSubstitutes(current, TypeConstants.CONSTRAINT_EQUAL);
if (equalSubstitutes != null) {
nextConstraint:
for (int j = 0, equalLength = equalSubstitutes.length; j < equalLength; j++) {
TypeBinding equalSubstitute = equalSubstitutes[j];
if (equalSubstitute == null) continue nextConstraint;
if (equalSubstitute == current) {
// try to find a better different match if any in subsequent equal candidates
for (int k = j + 1; k < equalLength; k++) {
equalSubstitute = equalSubstitutes[k];
if (equalSubstitute != current && equalSubstitute != null) {
substitutes[i] = equalSubstitute;
continue nextTypeParameter;
}
}
substitutes[i] = current;
continue nextTypeParameter;
}
// if (equalSubstitute.isTypeVariable()) {
// TypeVariableBinding variable = (TypeVariableBinding) equalSubstitute;
// // substituted by a variable of the same method, ignore
// if (variable.rank < varLength && typeVariables[variable.rank] == variable) {
// // TODO (philippe) rewrite all other constraints to use current instead.
// continue nextConstraint;
// }
// }
substitutes[i] = equalSubstitute;
continue
nextTypeParameter; // pick first match, applicability check will rule out invalid
// scenario where others were present
}
}
}
if (inferenceContext.hasUnresolvedTypeArgument()) {
// check Tj>:U constraints
nextTypeParameter:
for (int i = 0; i < varLength; i++) {
TypeVariableBinding current = typeVariables[i];
TypeBinding substitute = substitutes[i];
if (substitute != null) continue nextTypeParameter; // already inferred previously
TypeBinding[] bounds =
inferenceContext.getSubstitutes(current, TypeConstants.CONSTRAINT_SUPER);
if (bounds == null) continue nextTypeParameter;
TypeBinding mostSpecificSubstitute = scope.lowerUpperBound(bounds);
if (mostSpecificSubstitute == null) {
return false; // incompatible
}
if (mostSpecificSubstitute != TypeBinding.VOID) {
substitutes[i] = mostSpecificSubstitute;
}
}
}
if (considerEXTENDSConstraints && inferenceContext.hasUnresolvedTypeArgument()) {
// check Tj<:U constraints
nextTypeParameter:
for (int i = 0; i < varLength; i++) {
TypeVariableBinding current = typeVariables[i];
TypeBinding substitute = substitutes[i];
if (substitute != null) continue nextTypeParameter; // already inferred previously
TypeBinding[] bounds =
inferenceContext.getSubstitutes(current, TypeConstants.CONSTRAINT_EXTENDS);
if (bounds == null) continue nextTypeParameter;
TypeBinding[] glb = Scope.greaterLowerBound(bounds, scope, scope.environment());
TypeBinding mostSpecificSubstitute = null;
// https://bugs.eclipse.org/bugs/show_bug.cgi?id=341795 - Per 15.12.2.8, we should fully
// apply glb
if (glb != null) {
if (glb.length == 1) {
mostSpecificSubstitute = glb[0];
} else {
TypeBinding[] otherBounds = new TypeBinding[glb.length - 1];
System.arraycopy(glb, 1, otherBounds, 0, glb.length - 1);
mostSpecificSubstitute =
scope.environment().createWildcard(null, 0, glb[0], otherBounds, Wildcard.EXTENDS);
}
}
if (mostSpecificSubstitute != null) {
substitutes[i] = mostSpecificSubstitute;
}
}
}
return true;
}
