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lahodajlahodaj
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8268871: Adjust javac to updated exhaustiveness specification
Reviewed-by: vromero
1 parent 44691cc commit 4eb3212

2 files changed

Lines changed: 288 additions & 74 deletions

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‎src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java‎

Lines changed: 66 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -30,7 +30,7 @@
3030
import java.util.HashMap;
3131
import java.util.HashSet;
3232
import java.util.Set;
33-
import java.util.function.Predicate;
33+
import java.util.stream.StreamSupport;
3434

3535
import com.sun.source.tree.LambdaExpressionTree.BodyKind;
3636
import com.sun.tools.javac.code.*;
@@ -45,17 +45,16 @@
4545
import com.sun.tools.javac.util.JCDiagnostic.Error;
4646
import com.sun.tools.javac.util.JCDiagnostic.Warning;
4747

48-
import com.sun.tools.javac.code.Kinds.Kind;
4948
import com.sun.tools.javac.code.Symbol.*;
5049
import com.sun.tools.javac.tree.JCTree.*;
5150

5251
import static com.sun.tools.javac.code.Flags.*;
5352
import static com.sun.tools.javac.code.Flags.BLOCK;
5453
import static com.sun.tools.javac.code.Kinds.Kind.*;
54+
import com.sun.tools.javac.code.Type.TypeVar;
5555
import static com.sun.tools.javac.code.TypeTag.BOOLEAN;
5656
import static com.sun.tools.javac.code.TypeTag.VOID;
5757
import com.sun.tools.javac.resources.CompilerProperties.Fragments;
58-
import com.sun.tools.javac.tree.JCTree.JCParenthesizedPattern;
5958
import static com.sun.tools.javac.tree.JCTree.Tag.*;
6059
import com.sun.tools.javac.util.JCDiagnostic.Fragment;
6160

@@ -665,7 +664,7 @@ public void visitSwitch(JCSwitch tree) {
665664
ListBuffer<PendingExit> prevPendingExits = pendingExits;
666665
pendingExits = new ListBuffer<>();
667666
scan(tree.selector);
668-
Set<Object> constants = tree.patternSwitch ? allSwitchConstants(tree.selector) : null;
667+
Set<Symbol> constants = tree.patternSwitch ? new HashSet<>() : null;
669668
for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
670669
alive = Liveness.ALIVE;
671670
JCCase c = l.head;
@@ -687,8 +686,9 @@ public void visitSwitch(JCSwitch tree) {
687686
l.tail.head.pos(),
688687
Warnings.PossibleFallThroughIntoCase);
689688
}
690-
if ((constants == null || !constants.isEmpty()) && !tree.hasTotalPattern &&
691-
tree.patternSwitch && !TreeInfo.isErrorEnumSwitch(tree.selector, tree.cases)) {
689+
if (!tree.hasTotalPattern && tree.patternSwitch &&
690+
!TreeInfo.isErrorEnumSwitch(tree.selector, tree.cases) &&
691+
(constants == null || !isExhaustive(tree.selector.type, constants))) {
692692
log.error(tree, Errors.NotExhaustiveStatement);
693693
}
694694
if (!tree.hasTotalPattern) {
@@ -702,7 +702,7 @@ public void visitSwitchExpression(JCSwitchExpression tree) {
702702
ListBuffer<PendingExit> prevPendingExits = pendingExits;
703703
pendingExits = new ListBuffer<>();
704704
scan(tree.selector);
705-
Set<Object> constants = allSwitchConstants(tree.selector);
705+
Set<Symbol> constants = new HashSet<>();
706706
Liveness prevAlive = alive;
707707
for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
708708
alive = Liveness.ALIVE;
@@ -723,47 +723,83 @@ public void visitSwitchExpression(JCSwitchExpression tree) {
723723
}
724724
c.completesNormally = alive != Liveness.DEAD;
725725
}
726-
if ((constants == null || !constants.isEmpty()) && !tree.hasTotalPattern &&
727-
!TreeInfo.isErrorEnumSwitch(tree.selector, tree.cases)) {
726+
if (!tree.hasTotalPattern && !TreeInfo.isErrorEnumSwitch(tree.selector, tree.cases) &&
727+
!isExhaustive(tree.selector.type, constants)) {
728728
log.error(tree, Errors.NotExhaustive);
729729
}
730730
alive = prevAlive;
731731
alive = alive.or(resolveYields(tree, prevPendingExits));
732732
}
733733

734-
private Set<Object> allSwitchConstants(JCExpression selector) {
735-
Set<Object> constants = null;
736-
TypeSymbol selectorSym = selector.type.tsym;
737-
if ((selectorSym.flags() & ENUM) != 0) {
738-
constants = new HashSet<>();
739-
Predicate<Symbol> enumConstantFilter =
740-
s -> (s.flags() & ENUM) != 0 && s.kind == Kind.VAR;
741-
for (Symbol s : selectorSym.members().getSymbols(enumConstantFilter)) {
742-
constants.add(s.name);
743-
}
744-
} else if (selectorSym.isAbstract() && selectorSym.isSealed() && selectorSym.kind == Kind.TYP) {
745-
constants = new HashSet<>();
746-
constants.addAll(((ClassSymbol) selectorSym).permitted);
747-
}
748-
return constants;
749-
}
750-
751-
private void handleConstantCaseLabel(Set<Object> constants, JCCaseLabel pat) {
734+
private void handleConstantCaseLabel(Set<Symbol> constants, JCCaseLabel pat) {
752735
if (constants != null) {
753736
if (pat.isExpression()) {
754737
JCExpression expr = (JCExpression) pat;
755-
if (expr.hasTag(IDENT))
756-
constants.remove(((JCIdent) expr).name);
738+
if (expr.hasTag(IDENT) && ((JCIdent) expr).sym.isEnum())
739+
constants.add(((JCIdent) expr).sym);
757740
} else if (pat.isPattern()) {
758741
PatternPrimaryType patternType = TreeInfo.primaryPatternType((JCPattern) pat);
759742

760743
if (patternType.unconditional()) {
761-
constants.remove(patternType.type().tsym);
744+
constants.add(patternType.type().tsym);
762745
}
763746
}
764747
}
765748
}
766749

750+
private void transitiveCovers(Set<Symbol> covered) {
751+
List<Symbol> todo = List.from(covered);
752+
while (todo.nonEmpty()) {
753+
Symbol sym = todo.head;
754+
todo = todo.tail;
755+
switch (sym.kind) {
756+
case VAR -> {
757+
Iterable<Symbol> constants = sym.owner
758+
.members()
759+
.getSymbols(s -> s.isEnum() &&
760+
s.kind == VAR);
761+
boolean hasAll = StreamSupport.stream(constants.spliterator(), false)
762+
.allMatch(covered::contains);
763+
764+
if (hasAll && covered.add(sym.owner)) {
765+
todo = todo.prepend(sym.owner);
766+
}
767+
}
768+
769+
case TYP -> {
770+
for (Type sup : types.directSupertypes(sym.type)) {
771+
if (sup.tsym.kind == TYP && sup.tsym.isAbstract() && sup.tsym.isSealed()) {
772+
boolean hasAll = ((ClassSymbol) sup.tsym).permitted
773+
.stream()
774+
.allMatch(covered::contains);
775+
776+
if (hasAll && covered.add(sup.tsym)) {
777+
todo = todo.prepend(sup.tsym);
778+
}
779+
}
780+
}
781+
}
782+
}
783+
}
784+
}
785+
786+
private boolean isExhaustive(Type seltype, Set<Symbol> covered) {
787+
transitiveCovers(covered);
788+
return switch (seltype.getTag()) {
789+
case CLASS -> {
790+
if (seltype.isCompound()) {
791+
if (seltype.isIntersection()) {
792+
yield ((Type.IntersectionClassType) seltype).getComponents().stream().anyMatch(t -> isExhaustive(t, covered));
793+
}
794+
yield false;
795+
}
796+
yield covered.contains(seltype.tsym);
797+
}
798+
case TYPEVAR -> isExhaustive(((TypeVar) seltype).getUpperBound(), covered);
799+
default -> false;
800+
};
801+
}
802+
767803
public void visitTry(JCTry tree) {
768804
ListBuffer<PendingExit> prevPendingExits = pendingExits;
769805
pendingExits = new ListBuffer<>();

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