[NFC] Remove the now-dead PackExpanded accessors from AbstractionPattern

Author: rjmccall

include/swift/SIL/AbstractionPattern.h

@@ -1543,19 +1543,15 @@ class AbstractionPattern {
   AbstractionPattern getObjCMethodAsyncCompletionHandlerType(
                                      CanType swiftCompletionHandlerType) const;
 
-  /// Given that this is a pack expansion, invoke the given callback for
-  /// each component of the substituted expansion of this pattern.  The
-  /// pattern will be for a pack expansion type over a contextual type if
-  /// the substituted component is still a pack expansion.  If there aren't
-  /// substitutions available, this will just invoke the callback with the
-  /// component.
-  void forEachPackExpandedComponent(
-      llvm::function_ref<void(AbstractionPattern pattern)> fn) const;
-
+  /// Given that this is a pack expansion, return the number of components
+  /// that it should expand to.  This, and the general correctness of
+  /// traversing variadically generic tuple and function types under
+  /// substitution, relies on substitutions having been  set properly
+  /// on the abstraction pattern; without that, AbstractionPattern assumes
+  /// that every component expands to a single pack expansion component,
+  /// which will generally only work in specific situations.
   size_t getNumPackExpandedComponents() const;
 
-  SmallVector<AbstractionPattern, 4> getPackExpandedComponents() const;
-
   /// If this pattern refers to a foreign ObjC method that was imported as 
   /// async, return the bridged-back-to-ObjC completion handler type.
   CanType getObjCMethodAsyncCompletionHandlerForeignType(

lib/SIL/IR/AbstractionPattern.cpp

@@ -675,15 +675,6 @@ AbstractionPattern AbstractionPattern::getPackExpansionPatternType() const {
   llvm_unreachable("bad kind");
 }
 
-SmallVector<AbstractionPattern, 4>
-AbstractionPattern::getPackExpandedComponents() const {
-  SmallVector<AbstractionPattern, 4> result;
-  forEachPackExpandedComponent([&](AbstractionPattern pattern) {
-    result.push_back(pattern);
-  });
-  return result;
-}
-
 size_t AbstractionPattern::getNumPackExpandedComponents() const {
   assert(isPackExpansion());
   assert(getKind() == Kind::Type || getKind() == Kind::Discard);
@@ -699,40 +690,6 @@ size_t AbstractionPattern::getNumPackExpandedComponents() const {
   return substShape->getNumElements();
 }
 
-void AbstractionPattern::forEachPackExpandedComponent(
-          llvm::function_ref<void (AbstractionPattern)> fn) const {
-  assert(isPackExpansion());
-
-  switch (getKind()) {
-  case Kind::Type:
-  case Kind::Discard: {
-    // If we don't have generic substitutions, just produce this pattern.
-    if (!GenericSubs) return fn(*this);
-    auto origExpansion = cast<PackExpansionType>(getType());
-
-    // Substitute the expansion shape.
-    auto substShape = cast<PackType>(
-      origExpansion.getCountType().subst(GenericSubs)->getCanonicalType());
-
-    // Call the callback with each component of the substituted shape.
-    for (auto substShapeElt : substShape.getElementTypes()) {
-      CanType origEltType = origExpansion.getPatternType();
-      if (auto substShapeEltExpansion =
-            dyn_cast<PackExpansionType>(substShapeElt)) {
-        origEltType = CanPackExpansionType::get(origEltType,
-                                    substShapeEltExpansion.getCountType());
-      }
-      fn(AbstractionPattern(GenericSubs, GenericSig, origEltType));
-    }
-    return;
-  }
-
-  default:
-    llvm_unreachable("not a pack expansion");
-  }
-  llvm_unreachable("bad kind");
-}
-
 AbstractionPattern AbstractionPattern::removingMoveOnlyWrapper() const {
   switch (getKind()) {
   case Kind::Invalid: