forked from OSchip/llvm-project
423 lines
16 KiB
C++
423 lines
16 KiB
C++
//===-- lib/Semantics/pointer-assignment.cpp ------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "pointer-assignment.h"
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#include "flang/Common/idioms.h"
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#include "flang/Common/restorer.h"
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#include "flang/Evaluate/characteristics.h"
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#include "flang/Evaluate/expression.h"
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#include "flang/Evaluate/fold.h"
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#include "flang/Evaluate/tools.h"
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#include "flang/Parser/message.h"
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#include "flang/Parser/parse-tree-visitor.h"
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#include "flang/Parser/parse-tree.h"
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#include "flang/Semantics/expression.h"
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#include "flang/Semantics/symbol.h"
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#include "flang/Semantics/tools.h"
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#include "llvm/Support/raw_ostream.h"
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#include <optional>
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#include <set>
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#include <string>
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#include <type_traits>
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// Semantic checks for pointer assignment.
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namespace Fortran::semantics {
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using namespace parser::literals;
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using evaluate::characteristics::DummyDataObject;
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using evaluate::characteristics::FunctionResult;
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using evaluate::characteristics::Procedure;
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using evaluate::characteristics::TypeAndShape;
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using parser::MessageFixedText;
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using parser::MessageFormattedText;
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class PointerAssignmentChecker {
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public:
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PointerAssignmentChecker(evaluate::FoldingContext &context,
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parser::CharBlock source, const std::string &description)
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: context_{context}, source_{source}, description_{description} {}
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PointerAssignmentChecker(evaluate::FoldingContext &context, const Symbol &lhs)
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: context_{context}, source_{lhs.name()},
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description_{"pointer '"s + lhs.name().ToString() + '\''}, lhs_{&lhs},
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procedure_{Procedure::Characterize(lhs, context)} {
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set_lhsType(TypeAndShape::Characterize(lhs, context));
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set_isContiguous(lhs.attrs().test(Attr::CONTIGUOUS));
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set_isVolatile(lhs.attrs().test(Attr::VOLATILE));
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}
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PointerAssignmentChecker &set_lhsType(std::optional<TypeAndShape> &&);
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PointerAssignmentChecker &set_isContiguous(bool);
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PointerAssignmentChecker &set_isVolatile(bool);
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PointerAssignmentChecker &set_isBoundsRemapping(bool);
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bool Check(const SomeExpr &);
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private:
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template <typename T> bool Check(const T &);
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template <typename T> bool Check(const evaluate::Expr<T> &);
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template <typename T> bool Check(const evaluate::FunctionRef<T> &);
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template <typename T> bool Check(const evaluate::Designator<T> &);
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bool Check(const evaluate::NullPointer &);
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bool Check(const evaluate::ProcedureDesignator &);
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bool Check(const evaluate::ProcedureRef &);
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// Target is a procedure
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bool Check(
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parser::CharBlock rhsName, bool isCall, const Procedure * = nullptr);
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bool LhsOkForUnlimitedPoly() const;
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template <typename... A> parser::Message *Say(A &&...);
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evaluate::FoldingContext &context_;
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const parser::CharBlock source_;
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const std::string description_;
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const Symbol *lhs_{nullptr};
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std::optional<TypeAndShape> lhsType_;
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std::optional<Procedure> procedure_;
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bool isContiguous_{false};
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bool isVolatile_{false};
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bool isBoundsRemapping_{false};
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};
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PointerAssignmentChecker &PointerAssignmentChecker::set_lhsType(
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std::optional<TypeAndShape> &&lhsType) {
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lhsType_ = std::move(lhsType);
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return *this;
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}
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PointerAssignmentChecker &PointerAssignmentChecker::set_isContiguous(
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bool isContiguous) {
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isContiguous_ = isContiguous;
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return *this;
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}
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PointerAssignmentChecker &PointerAssignmentChecker::set_isVolatile(
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bool isVolatile) {
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isVolatile_ = isVolatile;
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return *this;
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}
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PointerAssignmentChecker &PointerAssignmentChecker::set_isBoundsRemapping(
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bool isBoundsRemapping) {
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isBoundsRemapping_ = isBoundsRemapping;
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return *this;
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}
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template <typename T> bool PointerAssignmentChecker::Check(const T &) {
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// Catch-all case for really bad target expression
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Say("Target associated with %s must be a designator or a call to a"
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" pointer-valued function"_err_en_US,
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description_);
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return false;
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}
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template <typename T>
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bool PointerAssignmentChecker::Check(const evaluate::Expr<T> &x) {
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return std::visit([&](const auto &x) { return Check(x); }, x.u);
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}
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bool PointerAssignmentChecker::Check(const SomeExpr &rhs) {
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if (HasVectorSubscript(rhs)) { // C1025
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Say("An array section with a vector subscript may not be a pointer target"_err_en_US);
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return false;
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} else if (ExtractCoarrayRef(rhs)) { // C1026
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Say("A coindexed object may not be a pointer target"_err_en_US);
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return false;
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} else {
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return std::visit([&](const auto &x) { return Check(x); }, rhs.u);
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}
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}
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bool PointerAssignmentChecker::Check(const evaluate::NullPointer &) {
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return true; // P => NULL() without MOLD=; always OK
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}
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template <typename T>
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bool PointerAssignmentChecker::Check(const evaluate::FunctionRef<T> &f) {
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std::string funcName;
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const auto *symbol{f.proc().GetSymbol()};
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if (symbol) {
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funcName = symbol->name().ToString();
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} else if (const auto *intrinsic{f.proc().GetSpecificIntrinsic()}) {
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funcName = intrinsic->name;
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}
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auto proc{Procedure::Characterize(f.proc(), context_)};
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if (!proc) {
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return false;
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}
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std::optional<MessageFixedText> msg;
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const auto &funcResult{proc->functionResult}; // C1025
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if (!funcResult) {
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msg = "%s is associated with the non-existent result of reference to"
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" procedure"_err_en_US;
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} else if (procedure_) {
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// Shouldn't be here in this function unless lhs is an object pointer.
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msg = "Procedure %s is associated with the result of a reference to"
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" function '%s' that does not return a procedure pointer"_err_en_US;
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} else if (funcResult->IsProcedurePointer()) {
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msg = "Object %s is associated with the result of a reference to"
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" function '%s' that is a procedure pointer"_err_en_US;
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} else if (!funcResult->attrs.test(FunctionResult::Attr::Pointer)) {
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msg = "%s is associated with the result of a reference to function '%s'"
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" that is a not a pointer"_err_en_US;
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} else if (isContiguous_ &&
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!funcResult->attrs.test(FunctionResult::Attr::Contiguous)) {
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msg = "CONTIGUOUS %s is associated with the result of reference to"
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" function '%s' that is not contiguous"_err_en_US;
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} else if (lhsType_) {
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const auto *frTypeAndShape{funcResult->GetTypeAndShape()};
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CHECK(frTypeAndShape);
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if (!lhsType_->IsCompatibleWith(context_.messages(), *frTypeAndShape,
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"pointer", "function result", false /*elemental*/,
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true /*left: deferred shape*/, true /*right: deferred shape*/)) {
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msg = "%s is associated with the result of a reference to function '%s'"
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" whose pointer result has an incompatible type or shape"_err_en_US;
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}
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}
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if (msg) {
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auto restorer{common::ScopedSet(lhs_, symbol)};
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Say(*msg, description_, funcName);
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return false;
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}
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return true;
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}
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template <typename T>
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bool PointerAssignmentChecker::Check(const evaluate::Designator<T> &d) {
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const Symbol *last{d.GetLastSymbol()};
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const Symbol *base{d.GetBaseObject().symbol()};
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if (!last || !base) {
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// P => "character literal"(1:3)
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context_.messages().Say("Pointer target is not a named entity"_err_en_US);
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return false;
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}
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std::optional<std::variant<MessageFixedText, MessageFormattedText>> msg;
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if (procedure_) {
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// Shouldn't be here in this function unless lhs is an object pointer.
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msg = "In assignment to procedure %s, the target is not a procedure or"
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" procedure pointer"_err_en_US;
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} else if (!evaluate::GetLastTarget(GetSymbolVector(d))) { // C1025
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msg = "In assignment to object %s, the target '%s' is not an object with"
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" POINTER or TARGET attributes"_err_en_US;
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} else if (auto rhsType{TypeAndShape::Characterize(d, context_)}) {
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if (!lhsType_) {
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msg = "%s associated with object '%s' with incompatible type or"
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" shape"_err_en_US;
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} else if (rhsType->corank() > 0 &&
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(isVolatile_ != last->attrs().test(Attr::VOLATILE))) { // C1020
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// TODO: what if A is VOLATILE in A%B%C? need a better test here
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if (isVolatile_) {
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msg = "Pointer may not be VOLATILE when target is a"
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" non-VOLATILE coarray"_err_en_US;
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} else {
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msg = "Pointer must be VOLATILE when target is a"
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" VOLATILE coarray"_err_en_US;
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}
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} else if (rhsType->type().IsUnlimitedPolymorphic()) {
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if (!LhsOkForUnlimitedPoly()) {
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msg = "Pointer type must be unlimited polymorphic or non-extensible"
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" derived type when target is unlimited polymorphic"_err_en_US;
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}
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} else {
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if (!lhsType_->type().IsTkCompatibleWith(rhsType->type())) {
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msg = MessageFormattedText{
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"Target type %s is not compatible with pointer type %s"_err_en_US,
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rhsType->type().AsFortran(), lhsType_->type().AsFortran()};
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} else if (!isBoundsRemapping_) {
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int lhsRank{evaluate::GetRank(lhsType_->shape())};
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int rhsRank{evaluate::GetRank(rhsType->shape())};
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if (lhsRank != rhsRank) {
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msg = MessageFormattedText{
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"Pointer has rank %d but target has rank %d"_err_en_US, lhsRank,
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rhsRank};
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}
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}
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}
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}
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if (msg) {
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auto restorer{common::ScopedSet(lhs_, last)};
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if (auto *m{std::get_if<MessageFixedText>(&*msg)}) {
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std::string buf;
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llvm::raw_string_ostream ss{buf};
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d.AsFortran(ss);
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Say(*m, description_, ss.str());
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} else {
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Say(std::get<MessageFormattedText>(*msg));
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}
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return false;
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}
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return true;
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}
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// Common handling for procedure pointer right-hand sides
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bool PointerAssignmentChecker::Check(
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parser::CharBlock rhsName, bool isCall, const Procedure *rhsProcedure) {
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if (std::optional<MessageFixedText> msg{
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evaluate::CheckProcCompatibility(isCall, procedure_, rhsProcedure)}) {
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Say(std::move(*msg), description_, rhsName);
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return false;
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}
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return true;
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}
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bool PointerAssignmentChecker::Check(const evaluate::ProcedureDesignator &d) {
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if (auto chars{Procedure::Characterize(d, context_)}) {
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return Check(d.GetName(), false, &*chars);
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} else {
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return Check(d.GetName(), false);
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}
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}
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bool PointerAssignmentChecker::Check(const evaluate::ProcedureRef &ref) {
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const Procedure *procedure{nullptr};
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auto chars{Procedure::Characterize(ref, context_)};
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if (chars) {
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procedure = &*chars;
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if (chars->functionResult) {
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if (const auto *proc{chars->functionResult->IsProcedurePointer()}) {
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procedure = proc;
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}
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}
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}
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return Check(ref.proc().GetName(), true, procedure);
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}
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// The target can be unlimited polymorphic if the pointer is, or if it is
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// a non-extensible derived type.
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bool PointerAssignmentChecker::LhsOkForUnlimitedPoly() const {
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const auto &type{lhsType_->type()};
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if (type.category() != TypeCategory::Derived || type.IsAssumedType()) {
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return false;
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} else if (type.IsUnlimitedPolymorphic()) {
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return true;
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} else {
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return !IsExtensibleType(&type.GetDerivedTypeSpec());
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}
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}
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template <typename... A>
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parser::Message *PointerAssignmentChecker::Say(A &&...x) {
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auto *msg{context_.messages().Say(std::forward<A>(x)...)};
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if (msg) {
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if (lhs_) {
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return evaluate::AttachDeclaration(msg, *lhs_);
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}
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if (!source_.empty()) {
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msg->Attach(source_, "Declaration of %s"_en_US, description_);
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}
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}
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return msg;
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}
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// Verify that any bounds on the LHS of a pointer assignment are valid.
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// Return true if it is a bound-remapping so we can perform further checks.
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static bool CheckPointerBounds(
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evaluate::FoldingContext &context, const evaluate::Assignment &assignment) {
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auto &messages{context.messages()};
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const SomeExpr &lhs{assignment.lhs};
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const SomeExpr &rhs{assignment.rhs};
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bool isBoundsRemapping{false};
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std::size_t numBounds{std::visit(
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common::visitors{
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[&](const evaluate::Assignment::BoundsSpec &bounds) {
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return bounds.size();
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},
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[&](const evaluate::Assignment::BoundsRemapping &bounds) {
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isBoundsRemapping = true;
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evaluate::ExtentExpr lhsSizeExpr{1};
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for (const auto &bound : bounds) {
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lhsSizeExpr = std::move(lhsSizeExpr) *
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(common::Clone(bound.second) - common::Clone(bound.first) +
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evaluate::ExtentExpr{1});
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}
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if (std::optional<std::int64_t> lhsSize{evaluate::ToInt64(
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evaluate::Fold(context, std::move(lhsSizeExpr)))}) {
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if (auto shape{evaluate::GetShape(context, rhs)}) {
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if (std::optional<std::int64_t> rhsSize{
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evaluate::ToInt64(evaluate::Fold(
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context, evaluate::GetSize(std::move(*shape))))}) {
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if (*lhsSize > *rhsSize) {
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messages.Say(
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"Pointer bounds require %d elements but target has"
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" only %d"_err_en_US,
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*lhsSize, *rhsSize); // 10.2.2.3(9)
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}
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}
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}
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}
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return bounds.size();
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},
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[](const auto &) -> std::size_t {
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DIE("not valid for pointer assignment");
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},
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},
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assignment.u)};
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if (numBounds > 0) {
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if (lhs.Rank() != static_cast<int>(numBounds)) {
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messages.Say("Pointer '%s' has rank %d but the number of bounds specified"
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" is %d"_err_en_US,
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lhs.AsFortran(), lhs.Rank(), numBounds); // C1018
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}
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}
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if (isBoundsRemapping && rhs.Rank() != 1 &&
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!evaluate::IsSimplyContiguous(rhs, context)) {
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messages.Say("Pointer bounds remapping target must have rank 1 or be"
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" simply contiguous"_err_en_US); // 10.2.2.3(9)
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}
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return isBoundsRemapping;
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}
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bool CheckPointerAssignment(
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evaluate::FoldingContext &context, const evaluate::Assignment &assignment) {
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return CheckPointerAssignment(context, assignment.lhs, assignment.rhs,
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CheckPointerBounds(context, assignment));
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}
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bool CheckPointerAssignment(evaluate::FoldingContext &context,
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const SomeExpr &lhs, const SomeExpr &rhs, bool isBoundsRemapping) {
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const Symbol *pointer{GetLastSymbol(lhs)};
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if (!pointer) {
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return false; // error was reported
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}
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if (!IsPointer(*pointer)) {
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evaluate::SayWithDeclaration(context.messages(), *pointer,
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"'%s' is not a pointer"_err_en_US, pointer->name());
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return false;
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}
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if (pointer->has<ProcEntityDetails>() && evaluate::ExtractCoarrayRef(lhs)) {
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context.messages().Say( // C1027
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"Procedure pointer may not be a coindexed object"_err_en_US);
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return false;
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}
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return PointerAssignmentChecker{context, *pointer}
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.set_isBoundsRemapping(isBoundsRemapping)
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.Check(rhs);
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}
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bool CheckPointerAssignment(
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evaluate::FoldingContext &context, const Symbol &lhs, const SomeExpr &rhs) {
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CHECK(IsPointer(lhs));
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return PointerAssignmentChecker{context, lhs}.Check(rhs);
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}
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bool CheckPointerAssignment(evaluate::FoldingContext &context,
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parser::CharBlock source, const std::string &description,
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const DummyDataObject &lhs, const SomeExpr &rhs) {
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return PointerAssignmentChecker{context, source, description}
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.set_lhsType(common::Clone(lhs.type))
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.set_isContiguous(lhs.attrs.test(DummyDataObject::Attr::Contiguous))
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.set_isVolatile(lhs.attrs.test(DummyDataObject::Attr::Volatile))
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.Check(rhs);
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}
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bool CheckInitialTarget(evaluate::FoldingContext &context,
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const SomeExpr &pointer, const SomeExpr &init) {
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return evaluate::IsInitialDataTarget(init, &context.messages()) &&
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CheckPointerAssignment(context, pointer, init);
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}
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} // namespace Fortran::semantics
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