[ConstraintLocator] NFC: Adjust name of isForKeyPathComponent to clarify its meaning

New name is `isInKeyPathComponent` since it's implemeneted as a
check for presence of `KeyPathComponent` element in the locator
that covers every sub-element contained in a key path component
as well.

Author: xedin

include/swift/Sema/ConstraintLocator.h

@@ -200,9 +200,9 @@ class ConstraintLocator : public llvm::FoldingSetNode {
   /// via key path dynamic member lookup.
   bool isForKeyPathDynamicMemberLookup() const;
 
-  /// Determine whether this locator points to one of the key path
-  /// components.
-  bool isForKeyPathComponent() const;
+  /// Determine whether this locator points to element inside
+  /// of a key path component.
+  bool isInKeyPathComponent() const;
 
   /// Determine whether this locator points to a result type of
   /// a key path component.

lib/Sema/CSDiagnostics.cpp

@@ -3975,7 +3975,7 @@ bool AllowTypeOrInstanceMemberFailure::diagnoseAsError() {
     // If this is a reference to a static member by one of the key path
     // components, let's provide a tailored diagnostic and return because
     // that is unsupported so there is no fix-it.
-    if (locator->isForKeyPathComponent()) {
+    if (locator->isInKeyPathComponent()) {
       InvalidStaticMemberRefInKeyPath failure(getSolution(), Member, locator);
       return failure.diagnoseAsError();
     }

lib/Sema/CSDiagnostics.h

@@ -1576,7 +1576,7 @@ class InvalidMemberRefInKeyPath : public FailureDiagnostic {
                             ConstraintLocator *locator)
       : FailureDiagnostic(solution, locator), Member(member) {
     assert(member->hasName());
-    assert(locator->isForKeyPathComponent() ||
+    assert(locator->isInKeyPathComponent() ||
            locator->isForKeyPathDynamicMemberLookup());
   }
 

lib/Sema/CSSimplify.cpp

@@ -8879,7 +8879,7 @@ ConstraintSystem::simplifyKeyPathConstraint(
     // than a hole. We need to come up with a better way of handling the
     // relationship between key paths and overloads.
     if (llvm::any_of(componentTypeVars, [&](TypeVariableType *tv) {
-          return tv->getImpl().getLocator()->isForKeyPathComponent() &&
+          return tv->getImpl().getLocator()->isInKeyPathComponent() &&
                  tv->getImpl().canBindToHole();
         })) {
       return SolutionKind::Solved;

lib/Sema/ConstraintLocator.cpp

@@ -171,7 +171,7 @@ bool ConstraintLocator::isForKeyPathDynamicMemberLookup() const {
   return !path.empty() && path.back().isKeyPathDynamicMember();
 }
 
-bool ConstraintLocator::isForKeyPathComponent() const {
+bool ConstraintLocator::isInKeyPathComponent() const {
   return llvm::any_of(getPath(), [&](const LocatorPathElt &elt) {
     return elt.isKeyPathComponent();
   });