Removed CdefinedInit warning and changed CDEFINED initialization to hard error

Author: eugeneepshteyn

flang/include/flang/Support/Fortran-features.h

@@ -73,7 +73,7 @@ ENUM_CLASS(UsageWarning, Portability, PointerToUndefinable,
     ZeroDoStep, UnusedForallIndex, OpenMPUsage, DataLength, IgnoredDirective,
     HomonymousSpecific, HomonymousResult, IgnoredIntrinsicFunctionType,
     PreviousScalarUse, RedeclaredInaccessibleComponent, ImplicitShared,
-    IndexVarRedefinition, IncompatibleImplicitInterfaces, CdefinedInit,
+    IndexVarRedefinition, IncompatibleImplicitInterfaces,
     VectorSubscriptFinalization, UndefinedFunctionResult, UselessIomsg,
     MismatchingDummyProcedure, SubscriptedEmptyArray, UnsignedLiteralTruncation,
     CompatibleDeclarationsFromDistinctModules, ConstantIsContiguous,

flang/lib/Semantics/resolve-names.cpp

@@ -9197,8 +9197,7 @@ bool DeclarationVisitor::CheckNonPointerInitialization(
         } else if (details->isCDefined()) {
           // CDEFINED variables cannot have initializer, because their storage
           // may come outside of Fortran.
-          context().Warn(common::UsageWarning::CdefinedInit, name.source,
-              "CDEFINED variable cannot be initialized"_warn_en_US);
+          Say(name, "CDEFINED variable cannot be initialized"_err_en_US);
         } else {
           return true;
         }

flang/test/Lower/cdefined.f90

@@ -1,10 +1,10 @@
 ! RUN: bbc -emit-hlfir -o - %s | FileCheck %s
 ! Ensure that CDEFINED variable has external (default) linkage and that
-! it doesn't have an initializer
+! it doesn't have either zero or constant initializer.
 module m
   use iso_c_binding
-  integer(c_int), bind(C, name='c_global', CDEFINED) :: c  = 42
+  integer(c_int), bind(C, name='c_global', CDEFINED) :: c
   ! CHECK: fir.global @c_global : i32
-  ! CHECK-NOT: fir.zero_bits 
-  ! CHECK-NOT: arith.constant 42
+  ! CHECK-NOT: fir.zero_bits
+  ! CHECK-NOT: arith.constant
 end

flang/test/Semantics/cdefined.f90

@@ -1,6 +1,6 @@
-! RUN: %python %S/test_errors.py %s %flang_fc1 -pedantic -Werror
+! RUN: %python %S/test_errors.py %s %flang_fc1
 module m
   use iso_c_binding
-  !WARNING: CDEFINED variable cannot be initialized [-Wcdefined-init]
+  !ERROR: CDEFINED variable cannot be initialized
   integer(c_int), bind(C, name='c_global', CDEFINED) :: c  = 42
 end