[flang] Fix LBOUND & UBOUND(function()), add tests

Original-commit: flang-compiler/f18@1e093e9927
Reviewed-on: https://github.com/flang-compiler/f18/pull/611
Tree-same-pre-rewrite: false

flang/lib/evaluate/expression.cc

@@ -85,11 +85,11 @@ std::optional<DynamicType> ExpressionBase<A>::GetType() const {
     return Result::GetType();
   } else {
     return std::visit(
-        [&](const auto &x) {
+        [&](const auto &x) -> std::optional<DynamicType> {
           if constexpr (!common::HasMember<decltype(x), TypelessExpression>) {
             return x.GetType();
           } else {
-            return std::optional<DynamicType>{};
+            return std::nullopt;
           }
         },
         derived().u);

flang/lib/evaluate/shape.cc

@@ -357,7 +357,31 @@ Shape GetUpperBounds(FoldingContext &context, const NamedEntity &base) {
 }
 
 void GetShapeVisitor::Handle(const Symbol &symbol) {
+  std::visit(
+      common::visitors{
+          [&](const semantics::ObjectEntityDetails &object) {
             Handle(NamedEntity{symbol});
+          },
+          [&](const semantics::AssocEntityDetails &assoc) {
+            Nested(assoc.expr());
+          },
+          [&](const semantics::SubprogramDetails &subp) {
+            if (subp.isFunction()) {
+              Handle(subp.result());
+            } else {
+              Return();
+            }
+          },
+          [&](const semantics::ProcBindingDetails &binding) {
+            Handle(binding.symbol());
+          },
+          [&](const semantics::UseDetails &use) { Handle(use.symbol()); },
+          [&](const semantics::HostAssocDetails &assoc) {
+            Handle(assoc.symbol());
+          },
+          [&](const auto &) { Return(); },
+      },
+      symbol.details());
 }
 
 void GetShapeVisitor::Handle(const Component &component) {
@@ -369,23 +393,21 @@ void GetShapeVisitor::Handle(const Component &component) {
 }
 
 void GetShapeVisitor::Handle(const NamedEntity &base) {
-  const Symbol &symbol{ResolveAssociations(base.GetLastSymbol())};
-  if (const auto *details{symbol.detailsIf<semantics::ObjectEntityDetails>()}) {
+  const Symbol &symbol{base.GetLastSymbol()};
+  if (const auto *object{symbol.detailsIf<semantics::ObjectEntityDetails>()}) {
     if (IsImpliedShape(symbol)) {
-      Nested(details->init());
+      Nested(object->init());
     } else {
       Shape result;
-      int n{static_cast<int>(details->shape().size())};
+      int n{static_cast<int>(object->shape().size())};
       for (int dimension{0}; dimension < n; ++dimension) {
         result.emplace_back(GetExtent(context_, base, dimension));
       }
       Return(std::move(result));
     }
-  } else if (const auto *details{
-                 symbol.detailsIf<semantics::AssocEntityDetails>()}) {
-    Nested(details->expr());
+  } else {
+    Return();  // error recovery
   }
-  Return();
 }
 
 void GetShapeVisitor::Handle(const Substring &substring) {

flang/test/evaluate/folding08.f90

@@ -15,6 +15,11 @@
 
 ! Test folding of LBOUND and UBOUND
 
+module m
+ contains
+  function foo()
+    real :: foo(2:3,4:6)
+  end function
   subroutine test(n1,a1,a2)
     integer, intent(in) :: n1
     real, intent(in) :: a1(0:n1), a2(0:*)
@@ -49,4 +54,9 @@ subroutine test(n1,a1,a2)
     logical, parameter :: test_lbca2 = all(lbca2 == [1])
     integer, parameter :: ubca2(:) = ubound(ca(:)(1:1))
     logical, parameter :: test_ubca2 = all(ubca2 == [3])
+    integer, parameter :: lbfoo(:) = lbound(foo())
+    logical, parameter :: test_lbfoo = all(lbfoo == [1,1])
+    integer, parameter :: ubfoo(:) = ubound(foo())
+    logical, parameter :: test_ubfoo = all(ubfoo == [2,3])
+  end subroutine
 end