[flang] CheckConformance: tristate-ify result

To ensure that errors are emitted by CheckConformance and
its callers in all situations, it's necessary for the returned result
of that function to distinguish between three possible
outcomes: the arrays are known to conform at compilation time,
the arrays are known to not conform (and a message has been
produced), and an indeterminate result in which is not possible
to determine conformance.  So convert CheckConformance's
result into an optional<bool>, and convert its confusing
Boolean flag arguments into a bit-set of named flags too.

Differential Revision: https://reviews.llvm.org/D103654

1 files changed, 1 insertions, 1 deletions

diff --git a/flang/lib/Semantics/pointer-assignment.cpp b/flang/lib/Semantics/pointer-assignment.cpp
index 8cf46f5..171e2ba 100644
--- a/flang/lib/Semantics/pointer-assignment.cpp
+++ b/flang/lib/Semantics/pointer-assignment.cpp
@@ -171,7 +171,7 @@ bool PointerAssignmentChecker::Check(const evaluate::FunctionRef<T> &f) {
     CHECK(frTypeAndShape);
     if (!lhsType_->IsCompatibleWith(context_.messages(), *frTypeAndShape,
             "pointer", "function result", false /*elemental*/,
-            true /*left: deferred shape*/, true /*right: deferred shape*/)) {
+            evaluate::CheckConformanceFlags::BothDeferredShape)) {
       msg = "%s is associated with the result of a reference to function '%s'"
             " whose pointer result has an incompatible type or shape"_err_en_US;
     }