[flang] Allow PROCEDURE() with explicit type elsewhere (#82835)

Fortran allows a procedure declaration statement with no interface or
type, with an explicit type declaration statement elsewhere being used
to define a function's result.

Fixes #82006.

Author: klausler

flang/include/flang/Semantics/symbol.h

@@ -419,7 +419,6 @@ class ProcEntityDetails : public EntityDetails, public WithPassArg {
 
   const Symbol *procInterface() const { return procInterface_; }
   void set_procInterface(const Symbol &sym) { procInterface_ = &sym; }
-  bool IsInterfaceSet() { return procInterface_ || type(); }
   inline bool HasExplicitInterface() const;
 
   // Be advised: !init().has_value() => uninitialized pointer,

flang/lib/Semantics/resolve-names.cpp

@@ -4976,13 +4976,13 @@ Symbol &DeclarationVisitor::DeclareProcEntity(
     const parser::Name &name, Attrs attrs, const Symbol *interface) {
   Symbol &symbol{DeclareEntity<ProcEntityDetails>(name, attrs)};
   if (auto *details{symbol.detailsIf<ProcEntityDetails>()}) {
-    if (details->IsInterfaceSet()) {
-      SayWithDecl(name, symbol,
-          "The interface for procedure '%s' has already been "
-          "declared"_err_en_US);
-      context().SetError(symbol);
+    if (context().HasError(symbol)) {
     } else if (HasCycle(symbol, interface)) {
       return symbol;
+    } else if (interface && (details->procInterface() || details->type())) {
+      SayWithDecl(name, symbol,
+          "The interface for procedure '%s' has already been declared"_err_en_US);
+      context().SetError(symbol);
     } else if (interface) {
       details->set_procInterface(*interface);
       if (interface->test(Symbol::Flag::Function)) {

flang/test/Semantics/resolve91.f90

@@ -4,7 +4,7 @@ module m
   procedure(real), pointer :: p
   !ERROR: EXTERNAL attribute was already specified on 'p'
   !ERROR: POINTER attribute was already specified on 'p'
-  !ERROR: The interface for procedure 'p' has already been declared
+  !ERROR: The type of 'p' has already been declared
   procedure(integer), pointer :: p
 end
 
@@ -82,3 +82,10 @@ module m8
   !ERROR: The type of 'pvar' has already been declared
   integer, pointer :: pVar => kVar
 end module m8
+
+module m9
+  integer :: p, q
+  procedure() p ! ok
+  !ERROR: The type of 'q' has already been declared
+  procedure(real) q
+end module m9