[C++2a] Implement operator<=>: Address bugs and post-commit review comments after r331677.

This patch addresses some mostly trivial post-commit review comments received
on r331677.

Additionally, this patch fixes an assertion in `getNarrowingKind` caused by
the use of an uninitialized value from `checkThreeWayNarrowingConversion`.

llvm-svn: 331707

2 files changed, 8 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index fb168957bd7..caa0b746439 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -8938,8 +8938,10 @@ QualType Sema::CheckComparisonCategoryType(ComparisonCategoryType Kind,
 
   // If lookup failed
   if (!Info) {
+    auto NameForDiags =
+        llvm::Twine("std::") + ComparisonCategories::getCategoryString(Kind);
     Diag(Loc, diag::err_implied_comparison_category_type_not_found)
-        << ComparisonCategories::getCategoryString(Kind);
+        << NameForDiags.str();
     return QualType();
   }
 
@@ -8947,7 +8949,7 @@ QualType Sema::CheckComparisonCategoryType(ComparisonCategoryType Kind,
   assert(Info->Record);
 
   // Update the Record decl in case we encountered a forward declaration on our
-  // first pass. FIXME(EricWF): This is a bit of a hack.
+  // first pass. FIXME: This is a bit of a hack.
   if (Info->Record->hasDefinition())
     Info->Record = Info->Record->getDefinition();
 
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 177cfd7354a..8522c04e73b 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -9757,12 +9757,12 @@ static bool checkThreeWayNarrowingConversion(Sema &S, QualType ToType, Expr *E,
                                              SourceLocation Loc) {
   // Check for a narrowing implicit conversion.
   StandardConversionSequence SCS;
+  SCS.setAsIdentityConversion();
   SCS.setToType(0, FromType);
   SCS.setToType(1, ToType);
-  if (const auto *ICE = dyn_cast<ImplicitCastExpr>(E)) {
-    auto CastK = ICE->getCastKind();
-    SCS.Second = castKindToImplicitConversionKind(CastK);
-  }
+  if (const auto *ICE = dyn_cast<ImplicitCastExpr>(E))
+    SCS.Second = castKindToImplicitConversionKind(ICE->getCastKind());
+
   APValue PreNarrowingValue;
   QualType PreNarrowingType;
   switch (SCS.getNarrowingKind(S.Context, E, PreNarrowingValue,