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//===-- lib/Semantics/definable.h -------------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Utilities for checking the definability of variables and pointers in context,
// including checks for attempted definitions in PURE subprograms.
// Fortran 2018 C1101, C1158, C1594, &c.
#include "flang/Common/enum-set.h"
#include "flang/Common/idioms.h"
#include "flang/Evaluate/expression.h"
#include "flang/Parser/char-block.h"
#include "flang/Parser/message.h"
#include <optional>
namespace Fortran::semantics {
class Symbol;
class Scope;
VectorSubscriptIsOk, // a vector subscript may appear (i.e., assignment)
DuplicatesAreOk, // vector subscript may have duplicates
PointerDefinition, // a pointer is being defined, not its target
AcceptAllocatable, // treat allocatable as if it were a pointer
PolymorphicOkInPure) // don't check for polymorphic type in pure subprogram
using DefinabilityFlags =
common::EnumSet<DefinabilityFlag, DefinabilityFlag_enumSize>;
// Tests a symbol or LHS variable or pointer for definability in a given scope.
// When the entity is not definable, returns a "because:" Message suitable for
// attachment to an error message to explain why the entity cannot be defined.
// When the entity can be defined in that context, returns std::nullopt.
std::optional<parser::Message> WhyNotDefinable(
parser::CharBlock, const Scope &, DefinabilityFlags, const Symbol &);
std::optional<parser::Message> WhyNotDefinable(parser::CharBlock, const Scope &,
DefinabilityFlags, const evaluate::Expr<evaluate::SomeType> &);
// If a symbol would not be definable in a pure scope, or not be usable as the
// target of a pointer assignment in a pure scope, return a constant string
// describing why.
const char *WhyBaseObjectIsSuspicious(const Symbol &, const Scope &);
} // namespace Fortran::semantics