ICU-21559 more guards for self-assignment

icu4c/source/common/edits.cpp

@@ -86,6 +86,7 @@ Edits &Edits::moveArray(Edits &src) U_NOEXCEPT {
 }
 
 Edits &Edits::operator=(const Edits &other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     length = other.length;
     delta = other.delta;
     numChanges = other.numChanges;

icu4c/source/i18n/cpdtrans.cpp

@@ -282,6 +282,7 @@ void CompoundTransliterator::freeTransliterators(void) {
 CompoundTransliterator& CompoundTransliterator::operator=(
                                              const CompoundTransliterator& t)
 {
+    if (this == &t) { return *this; }  // self-assignment: no-op
     Transliterator::operator=(t);
     int32_t i = 0;
     UBool failed = FALSE;

icu4c/source/i18n/dtfmtsym.cpp

@@ -450,6 +450,7 @@ DateFormatSymbols::copyData(const DateFormatSymbols& other) {
  */
 DateFormatSymbols& DateFormatSymbols::operator=(const DateFormatSymbols& other)
 {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     dispose();
     copyData(other);
 

icu4c/source/i18n/number_decimfmtprops.h

@@ -38,7 +38,7 @@ namespace impl {
 
 // Exported as U_I18N_API because it is a public member field of exported DecimalFormatProperties
 // Using this wrapper is rather unfortunate, but is needed on Windows platforms in order to allow
-// for DLL-exporting an fully specified template instantiation.
+// for DLL-exporting a fully specified template instantiation.
 class U_I18N_API CurrencyPluralInfoWrapper {
 public:
     LocalPointer<CurrencyPluralInfo> fPtr;
@@ -52,7 +52,8 @@ public:
     }
 
     CurrencyPluralInfoWrapper& operator=(const CurrencyPluralInfoWrapper& other) {
-        if (!other.fPtr.isNull()) {
+        if (this != &other &&  // self-assignment: no-op
+                !other.fPtr.isNull()) {
             fPtr.adoptInstead(new CurrencyPluralInfo(*other.fPtr));
         }
         return *this;

icu4c/source/i18n/number_fluent.cpp

@@ -442,6 +442,7 @@ LocalizedNumberFormatter::LocalizedNumberFormatter(NFS<LNF>&& src) U_NOEXCEPT
 }
 
 LocalizedNumberFormatter& LocalizedNumberFormatter::operator=(const LNF& other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     NFS<LNF>::operator=(static_cast<const NFS<LNF>&>(other));
     UErrorCode localStatus = U_ZERO_ERROR; // Can't bubble up the error
     lnfCopyHelper(other, localStatus);

icu4c/source/i18n/number_multiplier.cpp

@@ -46,6 +46,7 @@ Scale::Scale(const Scale& other)
 }
 
 Scale& Scale::operator=(const Scale& other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     fMagnitude = other.fMagnitude;
     if (other.fArbitrary != nullptr) {
         UErrorCode localStatus = U_ZERO_ERROR;

icu4c/source/i18n/number_usageprefs.cpp

@@ -34,6 +34,7 @@ StringProp::StringProp(const StringProp &other) : StringProp() {
 
 // Copy assignment operator
 StringProp &StringProp::operator=(const StringProp &other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     fLength = 0;
     fError = other.fError;
     if (fValue != nullptr) {

icu4c/source/i18n/numrange_fluent.cpp

@@ -245,6 +245,7 @@ LocalizedNumberRangeFormatter::LocalizedNumberRangeFormatter(NFS<LNF>&& src) U_N
 }
 
 LocalizedNumberRangeFormatter& LocalizedNumberRangeFormatter::operator=(const LNF& other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     NFS<LNF>::operator=(static_cast<const NFS<LNF>&>(other));
     // Do not steal; just clear
     delete fAtomicFormatter.exchange(nullptr);

icu4c/source/i18n/olsontz.cpp

@@ -274,6 +274,7 @@ OlsonTimeZone::OlsonTimeZone(const OlsonTimeZone& other) :
  * Assignment operator
  */
 OlsonTimeZone& OlsonTimeZone::operator=(const OlsonTimeZone& other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     canonicalID = other.canonicalID;
 
     transitionTimesPre32 = other.transitionTimesPre32;

icu4c/source/i18n/stsearch.cpp

@@ -184,7 +184,7 @@ StringSearch::clone() const {
 // operator overloading ---------------------------------------------
 StringSearch & StringSearch::operator=(const StringSearch &that)
 {
-    if ((*this) != that) {
+    if (this != &that) {
         UErrorCode status = U_ZERO_ERROR;
         m_text_          = that.m_text_;
         m_breakiterator_ = that.m_breakiterator_;

icu4c/source/i18n/translit.cpp

@@ -170,6 +170,7 @@ Transliterator* Transliterator::clone() const {
  * Assignment operator.
  */
 Transliterator& Transliterator::operator=(const Transliterator& other) {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     ID = other.ID;
     // NUL-terminate the ID string
     ID.getTerminatedBuffer();

icu4c/source/i18n/windtfmt.cpp

@@ -193,6 +193,7 @@ Win32DateFormat::~Win32DateFormat()
 
 Win32DateFormat &Win32DateFormat::operator=(const Win32DateFormat &other)
 {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     // The following handles fCalendar
     DateFormat::operator=(other);
 

icu4c/source/i18n/winnmfmt.cpp

@@ -268,6 +268,7 @@ Win32NumberFormat::~Win32NumberFormat()
 
 Win32NumberFormat &Win32NumberFormat::operator=(const Win32NumberFormat &other)
 {
+    if (this == &other) { return *this; }  // self-assignment: no-op
     NumberFormat::operator=(other);
 
     this->fCurrency          = other.fCurrency;

icu4c/source/test/intltest/numbertest_api.cpp

@@ -1209,6 +1209,7 @@ void NumberFormatterApiTest::unitArbitraryMeasureUnits() {
               .unit(MeasureUnit::forIdentifier("pow4-mile", status))
               .unitWidth(UNUM_UNIT_WIDTH_FULL_NAME)
               .locale("en-ZA");
+    lnf.operator=(lnf);  // self-assignment should be a no-op
     lnf.formatInt(1, status);
     status.expectErrorAndReset(U_RESOURCE_TYPE_MISMATCH);
 

icu4c/source/test/intltest/tsdtfmsy.cpp

@@ -149,6 +149,7 @@ void IntlTestDateFormatSymbols::TestGetSetSpecificItems()
         dataerrln("ERROR: Couldn't create English DateFormatSymbols " + (UnicodeString)u_errorName(status));
         return;
     }
+    symbol->operator=(*symbol);  // self-assignment should be a no-op
     int32_t cntFmtAbbrev, cntFmtShort, cntStdAloneShort;
     const UnicodeString * wdFmtAbbrev     = symbol->getWeekdays(cntFmtAbbrev,DateFormatSymbols::FORMAT,DateFormatSymbols::ABBREVIATED);
     const UnicodeString * wdFmtShort      = symbol->getWeekdays(cntFmtShort,DateFormatSymbols::FORMAT,DateFormatSymbols::SHORT);

icu4c/source/test/intltest/tztest.cpp

@@ -1171,8 +1171,10 @@ void TimeZoneTest::TestCustomParse()
         TimeZone *zone = TimeZone::createTimeZone(id);
         UnicodeString   itsID, temp;
 
-        if (dynamic_cast<OlsonTimeZone *>(zone) != NULL) {
+        OlsonTimeZone *ozone = dynamic_cast<OlsonTimeZone *>(zone);
+        if (ozone != nullptr) {
             logln(id + " -> Olson time zone");
+            ozone->operator=(*ozone);  // self-assignment should be a no-op
         } else {
             zone->getID(itsID);
             int32_t ioffset = zone->getRawOffset()/1000;