omitNeedlessWords: Fix self-type-stripping regression (#27742)

Turns out self-type-stripping /always/ operates on a type without
prefixes rather than /never/. Neither of these behaviors are really
what we'd want, but we'll live with it!

rdar://problem/56334797

Author: jrose-apple

lib/Basic/StringExtras.cpp

@@ -609,7 +609,7 @@ omitTrailingTypeNameWithSpecialCases(StringRef name,
 /// If there is no match, returns the end WordIterator for \p name.
 static Words::iterator matchTypeNameFromBackWithSpecialCases(
     StringRef name, OmissionTypeName typeName,
-    const InheritedNameSet *allPropertyNames, bool canSkipTypeSuffix = true) {
+    const InheritedNameSet *allPropertyNames) {
   // Get the camel-case words in the name and type name.
   auto nameWords = camel_case::getWords(name);
   auto typeWords = camel_case::getWords(typeName.Name);
@@ -697,7 +697,7 @@ static Words::iterator matchTypeNameFromBackWithSpecialCases(
     }
 
     // If this is a skippable suffix, skip it and keep looking.
-    if (canSkipTypeSuffix && nameWordRevIter == nameWordRevIterBegin) {
+    if (nameWordRevIter == nameWordRevIterBegin) {
       if (auto withoutSuffix = skipTypeSuffix(typeName.Name)) {
         typeName.Name = *withoutSuffix;
         typeWords = camel_case::getWords(typeName.Name);
@@ -724,8 +724,6 @@ omitSelfTypeFromBaseName(StringRef name, OmissionTypeName typeName,
   typeName.CollectionElement = StringRef();
 
   auto nameWords = camel_case::getWords(name);
-
-  bool canSkipTypeSuffix = true;
   Optional<llvm::iterator_range<WordIterator>> matchingRange;
 
   // Search backwards for the type name, whether anchored at the end or not.
@@ -734,8 +732,7 @@ omitSelfTypeFromBaseName(StringRef name, OmissionTypeName typeName,
        ++nameReverseIter) {
     StringRef matchName = nameReverseIter.base().getPriorStr();
     auto matchIter = matchTypeNameFromBackWithSpecialCases(matchName, typeName,
-                                                           allPropertyNames,
-                                                           canSkipTypeSuffix);
+                                                           allPropertyNames);
     auto matchIterInFullName = WordIterator(name, matchIter.getPosition());
     if (matchIterInFullName != nameReverseIter.base()) {
       matchingRange = llvm::make_range(matchIterInFullName,
@@ -746,7 +743,8 @@ omitSelfTypeFromBaseName(StringRef name, OmissionTypeName typeName,
     // Note: This behavior fell out of a previous implementation of
     // omit-needless-words, even though it probably wasn't intentional. At this
     // point, though, it could be source-breaking to change it.
-    canSkipTypeSuffix = false;
+    while (auto withoutSuffix = skipTypeSuffix(typeName.Name))
+      typeName.Name = *withoutSuffix;
   }
 
   // If we matched nothing, or if the type name was all the way at the start

test/IDE/Inputs/custom-modules/OmitNeedlessWords.h

@@ -79,3 +79,16 @@ typedef NS_OPTIONS(NSUInteger, OMWWobbleOptions) {
 -(void)conflicting1;
 @property (readonly) NSInteger conflictingProp1;
 @end
+
+@interface OMWObjectType : NSObject
+-(void)_enumerateObjectTypesWithHandler:(nonnull void (^)(void))handler;
+@end
+
+@interface OMWTerrifyingGarbage4DTypeRefMask_t : NSObject
+-(void)throwGarbageAway;
+-(void)throwGarbage4DAwayHarder;
+-(void)throwGarbage4DTypeRefMask_tAwayHardest;
+-(void)burnGarbage;
+-(void)carefullyBurnGarbage4D;
+-(void)veryCarefullyBurnGarbage4DTypeRefMask_t;
+@end

test/IDE/print_omit_needless_words.swift

@@ -300,6 +300,25 @@
 // CHECK-OMIT-NEEDLESS-WORDS-NEXT: func jumpSuper()
 // CHECK-OMIT-NEEDLESS-WORDS-NEXT: func joinSub()
 
+// CHECK-OMIT-NEEDLESS-WORDS-LABEL: class OMWObjectType
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func _enumerateTypes(handler: @escaping () -> Void)
+
+// CHECK-OMIT-NEEDLESS-WORDS-LABEL: class OMWTerrifyingGarbage4DTypeRefMask_t
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func throwAway()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: @available(swift, obsoleted: 3, renamed: "throwAway()")
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func throwGarbageAway()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func throwGarbage4DAwayHarder()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func throwGarbage4DTypeRefMask_tAwayHardest()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func burn()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: @available(swift, obsoleted: 3, renamed: "burn()")
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func burnGarbage()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func carefullyBurn()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: @available(swift, obsoleted: 3, renamed: "carefullyBurn()")
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func carefullyBurnGarbage4D()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func veryCarefullyBurn()
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: @available(swift, obsoleted: 3, renamed: "veryCarefullyBurn()")
+// CHECK-OMIT-NEEDLESS-WORDS-NEXT: func veryCarefullyBurnGarbage4DTypeRefMask_t()
+
 // CHECK-OMIT-NEEDLESS-WORDS-DIAGS: inconsistent Swift name for Objective-C method 'conflicting1' in 'OMWSub' ('waggle1()' in 'OMWWaggle' vs. 'wiggle1()' in 'OMWWiggle')
 // CHECK-OMIT-NEEDLESS-WORDS-DIAGS: inconsistent Swift name for Objective-C property 'conflictingProp1' in 'OMWSub' ('waggleProp1' in 'OMWWaggle' vs. 'wiggleProp1' in 'OMWSuper')