[flang] Add check for conflict of BIND(C) and Parameter attributes

The entity with BIND(C) attribute cannot be a named constant, so the
BIND(C) and parameter attributes are conflicted. Add check for it.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D126654

flang/lib/Semantics/check-declarations.cpp

@@ -1873,11 +1873,11 @@ static const std::string *DefinesBindCName(const Symbol &symbol) {
   }
 }
 
-// Check that BIND(C) names are distinct and BIND(C) variable declared in module
 void CheckHelper::CheckBindC(const Symbol &symbol) {
   if (!symbol.attrs().test(Attr::BIND_C)) {
     return;
   }
+  CheckConflicting(symbol, Attr::BIND_C, Attr::PARAMETER);
   if (symbol.has<ObjectEntityDetails>() && !symbol.owner().IsModule()) {
     messages_.Say(symbol.name(),
         "A variable with BIND(C) attribute may only appear in the specification part of a module"_err_en_US);

flang/test/Semantics/declarations02.f90

@@ -0,0 +1,32 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+
+module m
+  !ERROR: 'x1' may not have both the BIND(C) and PARAMETER attributes
+  integer, parameter, bind(c, name="a") :: x1 = 1
+  !ERROR: 'x2' may not have both the BIND(C) and PARAMETER attributes
+  integer, bind(c), parameter :: x2 = 1
+
+  !ERROR: 'x3' may not have both the BIND(C) and PARAMETER attributes
+  integer, parameter :: x3 = 1
+  bind(c) :: x3
+
+  type :: my_type1
+    integer :: x4
+  end type
+  type, bind(c) :: my_type2
+    integer :: x5
+  end type
+
+  !ERROR: 't1' may not have both the BIND(C) and PARAMETER attributes
+  type(my_type1), bind(c), parameter :: t1 = my_type1(1)
+  !ERROR: 't2' may not have both the BIND(C) and PARAMETER attributes
+  type(my_type2), bind(c), parameter :: t2 = my_type2(1)
+
+  type(my_type2), parameter :: t3 = my_type2(1) ! no error
+  !ERROR: 't4' may not have both the BIND(C) and PARAMETER attributes
+  type(my_type1), parameter :: t4 = my_type1(1)
+  !ERROR: 't5' may not have both the BIND(C) and PARAMETER attributes
+  type(my_type2), parameter :: t5 = my_type2(1)
+  bind(c) :: t4, t5
+
+end