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8289196: Pattern domination not working properly for record patterns #84

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8289196: Pattern domination not working properly for record patterns #84

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9d22eaf
8289196: Patttern domination not working property for record patterns
lahodaj Jun 28, 2022
220fcc1
Adding test, as suggested.
lahodaj Jul 1, 2022
bf740ed
Simplifying primitive pattern handling as suggested
lahodaj Jul 7, 2022
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28 changes: 4 additions & 24 deletions src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
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Expand Up @@ -1694,9 +1694,7 @@ private void handleSwitch(JCTree switchTree,

// Attribute all cases and
// check that there are no duplicate case labels or default clauses.
Set<Object> labels = new HashSet<>(); // The set of case labels.
List<Type> coveredTypesForPatterns = List.nil();
List<Type> coveredTypesForConstants = List.nil();
Set<Object> constants = new HashSet<>(); // The set of case constants.
boolean hasDefault = false; // Is there a default label?
boolean hasUnconditionalPattern = false; // Is there a unconditional pattern?
boolean lastPatternErroneous = false; // Has the last pattern erroneous type?
Expand Down Expand Up @@ -1732,10 +1730,8 @@ private void handleSwitch(JCTree switchTree,
Symbol sym = enumConstant(expr, seltype);
if (sym == null) {
log.error(expr.pos(), Errors.EnumLabelMustBeUnqualifiedEnum);
} else if (!labels.add(sym)) {
} else if (!constants.add(sym)) {
log.error(label.pos(), Errors.DuplicateCaseLabel);
} else {
checkCaseLabelDominated(label.pos(), coveredTypesForConstants, sym.type);
}
} else if (errorEnumSwitch) {
//error recovery: the selector is erroneous, and all the case labels
Expand Down Expand Up @@ -1765,10 +1761,8 @@ private void handleSwitch(JCTree switchTree,
}
} else if (!stringSwitch && !types.isAssignable(seltype, syms.intType)) {
log.error(label.pos(), Errors.ConstantLabelNotCompatible(pattype, seltype));
} else if (!labels.add(pattype.constValue())) {
} else if (!constants.add(pattype.constValue())) {
log.error(c.pos(), Errors.DuplicateCaseLabel);
} else {
checkCaseLabelDominated(label.pos(), coveredTypesForConstants, types.boxedTypeOrType(pattype));
}
}
}
Expand Down Expand Up @@ -1820,13 +1814,6 @@ private void handleSwitch(JCTree switchTree,
hasUnconditionalPattern = true;
}
lastPatternErroneous = patternType.isErroneous();
checkCaseLabelDominated(pat.pos(), coveredTypesForPatterns, patternType);
if (!patternType.isErroneous()) {
coveredTypesForConstants = coveredTypesForConstants.prepend(patternType);
if (unguarded) {
coveredTypesForPatterns = coveredTypesForPatterns.prepend(patternType);
}
}
} else {
Assert.error();
}
Expand All @@ -1850,6 +1837,7 @@ private void handleSwitch(JCTree switchTree,
}
if (patternSwitch) {
chk.checkSwitchCaseStructure(cases);
chk.checkSwitchCaseLabelDominated(cases);
}
if (switchTree.hasTag(SWITCH)) {
((JCSwitch) switchTree).hasUnconditionalPattern =
Expand All @@ -1875,14 +1863,6 @@ private static void addVars(List<JCStatement> stats, WriteableScope switchScope)
switchScope.enter(((JCVariableDecl) stat).sym);
}
}
private void checkCaseLabelDominated(DiagnosticPosition pos,
List<Type> coveredTypes, Type patternType) {
for (Type existing : coveredTypes) {
if (types.isSubtype(patternType, existing)) {
log.error(pos, Errors.PatternDominated);
}
}
}
// where
/** Return the selected enumeration constant symbol, or null. */
private Symbol enumConstant(JCTree tree, Type enumType) {
Expand Down
87 changes: 87 additions & 0 deletions src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java
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Expand Up @@ -4373,6 +4373,93 @@ void checkSwitchCaseStructure(List<JCCase> cases) {
}
}

void checkSwitchCaseLabelDominated(List<JCCase> cases) {
List<JCCaseLabel> caseLabels = List.nil();
for (List<JCCase> l = cases; l.nonEmpty(); l = l.tail) {
JCCase c = l.head;
for (JCCaseLabel label : c.labels) {
if (label.hasTag(DEFAULTCASELABEL) || TreeInfo.isNullCaseLabel(label)) {
continue;
}
Type currentType = labelType(label);
for (JCCaseLabel testCaseLabel : caseLabels) {
Type testType = labelType(testCaseLabel);
if (types.isSubtype(currentType, testType) &&
!currentType.hasTag(ERROR) && !testType.hasTag(ERROR)) {
//the current label is potentially dominated by the existing (test) label, check:
boolean dominated = false;
if (label instanceof JCConstantCaseLabel) {
dominated |= !(testCaseLabel instanceof JCConstantCaseLabel);
} else if (label instanceof JCPatternCaseLabel patternCL &&
testCaseLabel instanceof JCPatternCaseLabel testPatternCaseLabel &&
TreeInfo.unguardedCaseLabel(testCaseLabel)) {
dominated = patternDominated(testPatternCaseLabel.pat,
patternCL.pat);
}
if (dominated) {
log.error(label.pos(), Errors.PatternDominated);
}
}
}
caseLabels = caseLabels.prepend(label);
}
}
}
//where:
private Type labelType(JCCaseLabel label) {
return types.erasure(switch (label.getTag()) {
case PATTERNCASELABEL -> ((JCPatternCaseLabel) label).pat.type;
case CONSTANTCASELABEL -> types.boxedTypeOrType(((JCConstantCaseLabel) label).expr.type);
default -> throw Assert.error("Unexpected tree kind: " + label.getTag());
});
}
private boolean patternDominated(JCPattern existingPattern, JCPattern currentPattern) {
Type existingPatternType = types.erasure(existingPattern.type);
Type currentPatternType = types.erasure(currentPattern.type);
if (existingPatternType.isPrimitive() ^ currentPatternType.isPrimitive()) {
return false;
}
if (existingPatternType.isPrimitive()) {
return types.isSameType(existingPatternType, currentPatternType);
} else {
if (!types.isSubtype(currentPatternType, existingPatternType)) {
return false;
}
}
while (existingPattern instanceof JCParenthesizedPattern parenthesized) {
existingPattern = parenthesized.pattern;
}
while (currentPattern instanceof JCParenthesizedPattern parenthesized) {
currentPattern = parenthesized.pattern;
}
if (currentPattern instanceof JCBindingPattern) {
return existingPattern instanceof JCBindingPattern;
} else if (currentPattern instanceof JCRecordPattern currentRecordPattern) {
if (existingPattern instanceof JCBindingPattern) {
return true;
} else if (existingPattern instanceof JCRecordPattern existingRecordPattern) {
List<JCPattern> existingNested = existingRecordPattern.nested;
List<JCPattern> currentNested = currentRecordPattern.nested;
if (existingNested.size() != currentNested.size()) {
return false;
}
while (existingNested.nonEmpty()) {
if (!patternDominated(existingNested.head, currentNested.head)) {
return false;
}
existingNested = existingNested.tail;
currentNested = currentNested.tail;
}
return true;
} else {
Assert.error("Unknown pattern: " + existingPattern.getTag());
}
} else {
Assert.error("Unknown pattern: " + currentPattern.getTag());
}
return false;
}

/** check if a type is a subtype of Externalizable, if that is available. */
boolean isExternalizable(Type t) {
try {
Expand Down
75 changes: 75 additions & 0 deletions test/langtools/tools/javac/patterns/Domination.java
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Expand Up @@ -136,4 +136,79 @@ enum E {
}
}

int testRecordPatternsDominated1() {
record R(int a) {}
Object o = null;
switch (o) {
case R r: return 1;
case R(int a): return -1;
}
}

int testRecordPatternsDominated2() {
record R(int a) {}
Object o = null;
switch (o) {
case R(int a): return 1;
case R(int a): return -1;
}
}

int testRecordPatternsDominated3() {
record R(int a) {}
Object o = null;
switch (o) {
case R r when guard(): return 1;
case R(int a): return -1;
}
}

int testRecordPatternsDominated4() {
record R(int a) {}
Object o = null;
switch (o) {
case R(int a) when guard(): return 1;
case R(int a): return -1;
}
}

boolean guard() {
return false;
}

int testRecordPatternsDominated5() {
record R(int a) {}
Object o = null;
switch (o) {
case ((R r)): return 1;
case ((R(int a))): return -1;
}
}

int testRecordPatternsDominated6() {
record R(int a) {}
Object o = null;
switch (o) {
case ((R(int a))): return 1;
case ((R(int a))): return -1;
}
}

int testRecordPatternsDominated7() {
record R(int a) {}
Object o = null;
switch (o) {
case R r when true: return 1;
case R(int a): return -1;
}
}

int testRecordPatternsDominated8() {
record R(int a) {}
Object o = null;
switch (o) {
case R(int a) when true: return 1;
case R(int a): return -1;
}
}
}
8 changes: 7 additions & 1 deletion test/langtools/tools/javac/patterns/Domination.out
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Expand Up @@ -10,6 +10,12 @@ Domination.java:102:18: compiler.err.pattern.dominated
Domination.java:113:18: compiler.err.pattern.dominated
Domination.java:124:18: compiler.err.pattern.dominated
Domination.java:135:18: compiler.err.pattern.dominated
Domination.java:144:18: compiler.err.pattern.dominated
Domination.java:153:18: compiler.err.pattern.dominated
Domination.java:184:18: compiler.err.pattern.dominated
Domination.java:193:18: compiler.err.pattern.dominated
Domination.java:202:18: compiler.err.pattern.dominated
Domination.java:211:18: compiler.err.pattern.dominated
- compiler.note.preview.filename: Domination.java, DEFAULT
- compiler.note.preview.recompile
12 errors
18 errors
6 changes: 3 additions & 3 deletions test/langtools/tools/javac/patterns/SwitchErrors.out
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Expand Up @@ -32,11 +32,11 @@ SwitchErrors.java:172:18: compiler.err.pattern.expected
SwitchErrors.java:178:78: compiler.err.cant.resolve.location: kindname.variable, n, , , (compiler.misc.location: kindname.class, SwitchErrors, null)
SwitchErrors.java:184:73: compiler.err.cant.resolve.location: kindname.variable, n, , , (compiler.misc.location: kindname.class, SwitchErrors, null)
SwitchErrors.java:191:21: compiler.err.flows.through.to.pattern
SwitchErrors.java:200:44: compiler.err.pattern.dominated
SwitchErrors.java:200:44: compiler.err.flows.through.from.pattern
SwitchErrors.java:218:29: compiler.err.unconditional.pattern.and.default
SwitchErrors.java:225:21: compiler.err.flows.through.to.pattern
SwitchErrors.java:225:47: compiler.err.flows.through.from.pattern
SwitchErrors.java:232:44: compiler.err.pattern.dominated
SwitchErrors.java:232:44: compiler.err.flows.through.from.pattern
SwitchErrors.java:232:47: compiler.err.flows.through.from.pattern
SwitchErrors.java:244:18: compiler.err.duplicate.unconditional.pattern
SwitchErrors.java:249:18: compiler.err.prob.found.req: (compiler.misc.not.applicable.types: int, java.lang.Integer)
Expand All @@ -55,4 +55,4 @@ SwitchErrors.java:164:9: compiler.err.not.exhaustive.statement
SwitchErrors.java:237:9: compiler.err.not.exhaustive.statement
- compiler.note.preview.filename: SwitchErrors.java, DEFAULT
- compiler.note.preview.recompile
55 errors
55 errors