llvm/flang/lib/semantics/check-io.cc

// Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "check-io.h"
#include "expression.h"
#include "tools.h"
#include "../parser/tools.h"

namespace Fortran::semantics {

// TODO: C1234, C1235 -- defined I/O constraints

void IoChecker::Enter(const parser::ConnectSpec &spec) {
  // ConnectSpec context FileNameExpr
  if (std::get_if<parser::FileNameExpr>(&spec.u)) {
    SetSpecifier(IoSpecKind::File);
  }
}

void IoChecker::Enter(const parser::ConnectSpec::CharExpr &spec) {
  IoSpecKind specKind{};
  using ParseKind = parser::ConnectSpec::CharExpr::Kind;
  switch (std::get<ParseKind>(spec.t)) {
  case ParseKind::Access: specKind = IoSpecKind::Access; break;
  case ParseKind::Action: specKind = IoSpecKind::Action; break;
  case ParseKind::Asynchronous: specKind = IoSpecKind::Asynchronous; break;
  case ParseKind::Blank: specKind = IoSpecKind::Blank; break;
  case ParseKind::Decimal: specKind = IoSpecKind::Decimal; break;
  case ParseKind::Delim: specKind = IoSpecKind::Delim; break;
  case ParseKind::Encoding: specKind = IoSpecKind::Encoding; break;
  case ParseKind::Form: specKind = IoSpecKind::Form; break;
  case ParseKind::Pad: specKind = IoSpecKind::Pad; break;
  case ParseKind::Position: specKind = IoSpecKind::Position; break;
  case ParseKind::Round: specKind = IoSpecKind::Round; break;
  case ParseKind::Sign: specKind = IoSpecKind::Sign; break;
  case ParseKind::Convert: specKind = IoSpecKind::Convert; break;
  case ParseKind::Dispose: specKind = IoSpecKind::Dispose; break;
  }
  SetSpecifier(specKind);
  if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
          std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
    std::string s{parser::ToUpperCaseLetters(*charConst)};
    if (specKind == IoSpecKind::Access) {
      flags_.set(Flag::KnownAccess);
      flags_.set(Flag::AccessDirect, s == "DIRECT");
      flags_.set(Flag::AccessStream, s == "STREAM");
    }
    CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
  }
}

void IoChecker::Enter(const parser::ConnectSpec::Newunit &) {
  SetSpecifier(IoSpecKind::Newunit);
}

void IoChecker::Enter(const parser::ConnectSpec::Recl &spec) {
  SetSpecifier(IoSpecKind::Recl);
  if (const std::optional<std::int64_t> recl{
          GetConstExpr<std::int64_t>(spec)}) {
    if (*recl <= 0) {
      context_.Say(parser::FindSourceLocation(spec),
          "RECL value (%jd) must be positive"_err_en_US,
          std::move(static_cast<std::intmax_t>(*recl)));  // 12.5.6.15
    }
  }
}

void IoChecker::Enter(const parser::EndLabel &spec) {
  SetSpecifier(IoSpecKind::End);
}

void IoChecker::Enter(const parser::EorLabel &spec) {
  SetSpecifier(IoSpecKind::Eor);
}

void IoChecker::Enter(const parser::ErrLabel &spec) {
  SetSpecifier(IoSpecKind::Err);
}

void IoChecker::Enter(const parser::FileUnitNumber &spec) {
  SetSpecifier(IoSpecKind::Unit);
  flags_.set(Flag::NumberUnit);
}

void IoChecker::Enter(const parser::Format &spec) {
  SetSpecifier(IoSpecKind::Fmt);
  flags_.set(Flag::FmtOrNml);
  if (std::get_if<parser::Star>(&spec.u)) {
    flags_.set(Flag::StarFmt);
  } else if (std::get_if<parser::Label>(&spec.u)) {
    // Format statement format should be validated elsewhere.
    flags_.set(Flag::LabelFmt);
  } else {
    flags_.set(Flag::CharFmt);
    // TODO: validate compile-time constant format -- 12.6.2.2
  }
}

void IoChecker::Enter(const parser::IdExpr &spec) {
  SetSpecifier(IoSpecKind::Id);
}

void IoChecker::Enter(const parser::IdVariable &spec) {
  SetSpecifier(IoSpecKind::Id);
  auto expr{GetExpr(spec)};
  if (expr == nullptr || !expr->GetType()) {
    return;
  }
  int kind{expr->GetType()->kind};
  int defaultKind{
      context_.defaultKinds().GetDefaultKind(TypeCategory::Integer)};
  if (kind < defaultKind) {
    context_.Say(
        "ID kind (%d) is smaller than default INTEGER kind (%d)"_err_en_US,
        std::move(kind), std::move(defaultKind));  // C1229
  }
}

void IoChecker::Enter(const parser::InputItem &spec) {
  flags_.set(Flag::DataList);
  if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
    const parser::Name &name{GetLastName(*var)};
    if (auto *details{name.symbol->detailsIf<ObjectEntityDetails>()}) {
      // TODO: Determine if this check is needed at all, and if so, replace
      // the false subcondition with a check for a whole array.  Otherwise,
      // the check incorrectly flags array element and section references.
      if (details->IsAssumedSize() && false) {
        // This check may be superseded by C928 or C1002.
        context_.Say(name.source,
            "'%s' must not be a whole assumed size array"_err_en_US,
            name.ToString().c_str());  // C1231
      }
    }
  }
}

void IoChecker::Enter(const parser::InquireSpec &spec) {
  // InquireSpec context FileNameExpr
  if (std::get_if<parser::FileNameExpr>(&spec.u)) {
    SetSpecifier(IoSpecKind::File);
  }
}

void IoChecker::Enter(const parser::InquireSpec::CharVar &spec) {
  IoSpecKind specKind{};
  using ParseKind = parser::InquireSpec::CharVar::Kind;
  switch (std::get<ParseKind>(spec.t)) {
  case ParseKind::Access: specKind = IoSpecKind::Access; break;
  case ParseKind::Action: specKind = IoSpecKind::Action; break;
  case ParseKind::Asynchronous: specKind = IoSpecKind::Asynchronous; break;
  case ParseKind::Blank: specKind = IoSpecKind::Blank; break;
  case ParseKind::Decimal: specKind = IoSpecKind::Decimal; break;
  case ParseKind::Delim: specKind = IoSpecKind::Delim; break;
  case ParseKind::Direct: specKind = IoSpecKind::Direct; break;
  case ParseKind::Encoding: specKind = IoSpecKind::Encoding; break;
  case ParseKind::Form: specKind = IoSpecKind::Form; break;
  case ParseKind::Formatted: specKind = IoSpecKind::Formatted; break;
  case ParseKind::Iomsg: specKind = IoSpecKind::Iomsg; break;
  case ParseKind::Name: specKind = IoSpecKind::Name; break;
  case ParseKind::Pad: specKind = IoSpecKind::Pad; break;
  case ParseKind::Position: specKind = IoSpecKind::Position; break;
  case ParseKind::Read: specKind = IoSpecKind::Read; break;
  case ParseKind::Readwrite: specKind = IoSpecKind::Readwrite; break;
  case ParseKind::Round: specKind = IoSpecKind::Round; break;
  case ParseKind::Sequential: specKind = IoSpecKind::Sequential; break;
  case ParseKind::Sign: specKind = IoSpecKind::Sign; break;
  case ParseKind::Status: specKind = IoSpecKind::Status; break;
  case ParseKind::Stream: specKind = IoSpecKind::Stream; break;
  case ParseKind::Unformatted: specKind = IoSpecKind::Unformatted; break;
  case ParseKind::Write: specKind = IoSpecKind::Write; break;
  case ParseKind::Convert: specKind = IoSpecKind::Convert; break;
  case ParseKind::Dispose: specKind = IoSpecKind::Dispose; break;
  }
  SetSpecifier(specKind);
}

void IoChecker::Enter(const parser::InquireSpec::IntVar &spec) {
  IoSpecKind specKind{};
  using ParseKind = parser::InquireSpec::IntVar::Kind;
  switch (std::get<parser::InquireSpec::IntVar::Kind>(spec.t)) {
  case ParseKind::Iostat: specKind = IoSpecKind::Iostat; break;
  case ParseKind::Nextrec: specKind = IoSpecKind::Nextrec; break;
  case ParseKind::Number: specKind = IoSpecKind::Number; break;
  case ParseKind::Pos: specKind = IoSpecKind::Pos; break;
  case ParseKind::Recl: specKind = IoSpecKind::Recl; break;
  case ParseKind::Size: specKind = IoSpecKind::Size; break;
  }
  SetSpecifier(specKind);
}

void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
  IoSpecKind specKind{};
  using ParseKind = parser::InquireSpec::LogVar::Kind;
  switch (std::get<parser::InquireSpec::LogVar::Kind>(spec.t)) {
  case ParseKind::Exist: specKind = IoSpecKind::Exist; break;
  case ParseKind::Named: specKind = IoSpecKind::Named; break;
  case ParseKind::Opened: specKind = IoSpecKind::Opened; break;
  case ParseKind::Pending: specKind = IoSpecKind::Pending; break;
  }
  SetSpecifier(specKind);
}

void IoChecker::Enter(const parser::IoControlSpec &spec) {
  // IoControlSpec context Name
  flags_.set(Flag::IoControlList);
  if (std::holds_alternative<parser::Name>(spec.u)) {
    SetSpecifier(IoSpecKind::Nml);
    flags_.set(Flag::FmtOrNml);
  }
}

void IoChecker::Enter(const parser::IoControlSpec::Asynchronous &spec) {
  SetSpecifier(IoSpecKind::Asynchronous);
  if (const std::optional<std::string> charConst{
          GetConstExpr<std::string>(spec)}) {
    flags_.set(
        Flag::AsynchronousYes, parser::ToUpperCaseLetters(*charConst) == "YES");
    CheckStringValue(IoSpecKind::Asynchronous, *charConst,
        parser::FindSourceLocation(spec));  // C1223
  }
}

void IoChecker::Enter(const parser::IoControlSpec::CharExpr &spec) {
  IoSpecKind specKind{};
  using ParseKind = parser::IoControlSpec::CharExpr::Kind;
  switch (std::get<ParseKind>(spec.t)) {
  case ParseKind::Advance: specKind = IoSpecKind::Advance; break;
  case ParseKind::Blank: specKind = IoSpecKind::Blank; break;
  case ParseKind::Decimal: specKind = IoSpecKind::Decimal; break;
  case ParseKind::Delim: specKind = IoSpecKind::Delim; break;
  case ParseKind::Pad: specKind = IoSpecKind::Pad; break;
  case ParseKind::Round: specKind = IoSpecKind::Round; break;
  case ParseKind::Sign: specKind = IoSpecKind::Sign; break;
  }
  SetSpecifier(specKind);
  if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
          std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
    if (specKind == IoSpecKind::Advance) {
      flags_.set(
          Flag::AdvanceYes, parser::ToUpperCaseLetters(*charConst) == "YES");
    }
    CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
  }
}

void IoChecker::Enter(const parser::IoControlSpec::Pos &spec) {
  SetSpecifier(IoSpecKind::Pos);
}

void IoChecker::Enter(const parser::IoControlSpec::Rec &spec) {
  SetSpecifier(IoSpecKind::Rec);
}

void IoChecker::Enter(const parser::IoControlSpec::Size &spec) {
  SetSpecifier(IoSpecKind::Size);
}

void IoChecker::Enter(const parser::IoUnit &spec) {
  if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
    // TODO: C1201 - internal file variable must not be an array section ...
    if (auto expr{GetExpr(*var)}) {
      if (!ExprTypeKindIsDefault(*expr, context_)) {
        // This may be too restrictive; other kinds may be valid.
        context_.Say(  // C1202
            "invalid character kind for an internal file variable"_err_en_US);
      }
    }
    SetSpecifier(IoSpecKind::Unit);
    flags_.set(Flag::InternalUnit);
  } else if (std::get_if<parser::Star>(&spec.u)) {
    SetSpecifier(IoSpecKind::Unit);
    flags_.set(Flag::StarUnit);
  }
}

void IoChecker::Enter(const parser::MsgVariable &spec) {
  SetSpecifier(IoSpecKind::Iomsg);
}

void IoChecker::Enter(const parser::OutputItem &spec) {
  flags_.set(Flag::DataList);
  // TODO: C1233 - output item must not be a procedure pointer
}

void IoChecker::Enter(const parser::StatusExpr &spec) {
  SetSpecifier(IoSpecKind::Status);
  if (const std::optional<std::string> charConst{
          GetConstExpr<std::string>(spec)}) {
    // Status values for Open and Close are different.
    std::string s{parser::ToUpperCaseLetters(*charConst)};
    if (stmt_ == IoStmtKind::Open) {
      flags_.set(Flag::KnownStatus);
      flags_.set(Flag::StatusNew, s == "NEW");
      flags_.set(Flag::StatusReplace, s == "REPLACE");
      flags_.set(Flag::StatusScratch, s == "SCRATCH");
      // CheckStringValue compares for OPEN Status string values.
      CheckStringValue(
          IoSpecKind::Status, *charConst, parser::FindSourceLocation(spec));
      return;
    }
    CHECK(stmt_ == IoStmtKind::Close);
    if (s != "DELETE" && s != "KEEP") {
      context_.Say(parser::FindSourceLocation(spec),
          "invalid STATUS value '%s'"_err_en_US, (*charConst).c_str());
    }
  }
}

void IoChecker::Enter(const parser::StatVariable &spec) {
  SetSpecifier(IoSpecKind::Iostat);
}

void IoChecker::Leave(const parser::BackspaceStmt &stmt) {
  CheckForRequiredSpecifier(
      flags_.test(Flag::NumberUnit), "UNIT number");  // C1240
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::CloseStmt &stmt) {
  CheckForRequiredSpecifier(
      flags_.test(Flag::NumberUnit), "UNIT number");  // C1208
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::EndfileStmt &stmt) {
  CheckForRequiredSpecifier(
      flags_.test(Flag::NumberUnit), "UNIT number");  // C1240
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::FlushStmt &stmt) {
  CheckForRequiredSpecifier(
      flags_.test(Flag::NumberUnit), "UNIT number");  // C1243
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::InquireStmt &stmt) {
  if (std::get_if<std::list<parser::InquireSpec>>(&stmt.u)) {
    // Inquire by unit or by file (vs. by output list).
    CheckForRequiredSpecifier(
        flags_.test(Flag::NumberUnit) || specifierSet_.test(IoSpecKind::File),
        "UNIT number or FILE");  // C1246
    CheckForProhibitedSpecifier(IoSpecKind::File, IoSpecKind::Unit);  // C1246
    CheckForRequiredSpecifier(IoSpecKind::Id, IoSpecKind::Pending);  // C1248
  }
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::OpenStmt &stmt) {
  CheckForRequiredSpecifier(specifierSet_.test(IoSpecKind::Unit) ||
          specifierSet_.test(IoSpecKind::Newunit),
      "UNIT or NEWUNIT");  // C1204, C1205
  CheckForProhibitedSpecifier(
      IoSpecKind::Newunit, IoSpecKind::Unit);  // C1204, C1205
  CheckForRequiredSpecifier(flags_.test(Flag::StatusNew), "STATUS='NEW'",
      IoSpecKind::File);  // 12.5.6.10
  CheckForRequiredSpecifier(flags_.test(Flag::StatusReplace),
      "STATUS='REPLACE'", IoSpecKind::File);  // 12.5.6.10
  CheckForProhibitedSpecifier(flags_.test(Flag::StatusScratch),
      "STATUS='SCRATCH'", IoSpecKind::File);  // 12.5.6.10
  if (flags_.test(Flag::KnownStatus)) {
    CheckForRequiredSpecifier(IoSpecKind::Newunit,
        specifierSet_.test(IoSpecKind::File) ||
            flags_.test(Flag::StatusScratch),
        "FILE or STATUS='SCRATCH'");  // 12.5.6.12
  } else {
    CheckForRequiredSpecifier(IoSpecKind::Newunit,
        specifierSet_.test(IoSpecKind::File) ||
            specifierSet_.test(IoSpecKind::Status),
        "FILE or STATUS");  // 12.5.6.12
  }
  if (flags_.test(Flag::KnownAccess)) {
    CheckForRequiredSpecifier(flags_.test(Flag::AccessDirect),
        "ACCESS='DIRECT'", IoSpecKind::Recl);  // 12.5.6.15
    CheckForProhibitedSpecifier(flags_.test(Flag::AccessStream),
        "STATUS='STREAM'", IoSpecKind::Recl);  // 12.5.6.15
  }
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::ReadStmt &stmt) {
  if (!flags_.test(Flag::IoControlList)) {
    return;
  }
  LeaveReadWrite();
  CheckForProhibitedSpecifier(IoSpecKind::Delim);  // C1212
  CheckForProhibitedSpecifier(IoSpecKind::Sign);  // C1212
  CheckForProhibitedSpecifier(IoSpecKind::Rec, IoSpecKind::End);  // C1220
  CheckForRequiredSpecifier(IoSpecKind::Eor,
      specifierSet_.test(IoSpecKind::Advance) && !flags_.test(Flag::AdvanceYes),
      "ADVANCE with value 'NO'");  // C1222 + 12.6.2.1p2
  CheckForRequiredSpecifier(IoSpecKind::Blank, flags_.test(Flag::FmtOrNml),
      "FMT or NML");  // C1227
  CheckForRequiredSpecifier(
      IoSpecKind::Pad, flags_.test(Flag::FmtOrNml), "FMT or NML");  // C1227
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::RewindStmt &stmt) {
  CheckForRequiredSpecifier(
      flags_.test(Flag::NumberUnit), "UNIT number");  // C1240
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::WaitStmt &stmt) {
  CheckForRequiredSpecifier(
      flags_.test(Flag::NumberUnit), "UNIT number");  // C1237
  stmt_ = IoStmtKind::None;
}

void IoChecker::Leave(const parser::WriteStmt &stmt) {
  LeaveReadWrite();
  CheckForProhibitedSpecifier(IoSpecKind::Blank);  // C1213
  CheckForProhibitedSpecifier(IoSpecKind::End);  // C1213
  CheckForProhibitedSpecifier(IoSpecKind::Eor);  // C1213
  CheckForProhibitedSpecifier(IoSpecKind::Pad);  // C1213
  CheckForProhibitedSpecifier(IoSpecKind::Size);  // C1213
  CheckForRequiredSpecifier(
      IoSpecKind::Sign, flags_.test(Flag::FmtOrNml), "FMT or NML");  // C1227
  CheckForRequiredSpecifier(IoSpecKind::Delim,
      flags_.test(Flag::StarFmt) || specifierSet_.test(IoSpecKind::Nml),
      "FMT=* or NML");  // C1228
  stmt_ = IoStmtKind::None;
}

void IoChecker::LeaveReadWrite() const {
  CheckForRequiredSpecifier(IoSpecKind::Unit);  // C1211
  CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Rec);  // C1216
  CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Fmt);  // C1216
  CheckForProhibitedSpecifier(
      IoSpecKind::Nml, flags_.test(Flag::DataList), "a data list");  // C1216
  CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
      "UNIT=internal-file", IoSpecKind::Pos);  // C1219
  CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
      "UNIT=internal-file", IoSpecKind::Rec);  // C1219
  CheckForProhibitedSpecifier(
      flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Pos);  // C1219
  CheckForProhibitedSpecifier(
      flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Rec);  // C1219
  CheckForProhibitedSpecifier(
      IoSpecKind::Rec, flags_.test(Flag::StarFmt), "FMT=*");  // C1220
  CheckForRequiredSpecifier(IoSpecKind::Advance,
      flags_.test(Flag::CharFmt) || flags_.test(Flag::LabelFmt),
      "an explicit format");  // C1221
  CheckForProhibitedSpecifier(IoSpecKind::Advance,
      flags_.test(Flag::InternalUnit), "UNIT=internal-file");  // C1221
  CheckForRequiredSpecifier(flags_.test(Flag::AsynchronousYes),
      "ASYNCHRONOUS='YES'", flags_.test(Flag::NumberUnit),
      "UNIT=number");  // C1224
  CheckForRequiredSpecifier(IoSpecKind::Id, flags_.test(Flag::AsynchronousYes),
      "ASYNCHRONOUS='YES'");  // C1225
  CheckForProhibitedSpecifier(IoSpecKind::Pos, IoSpecKind::Rec);  // C1226
  CheckForRequiredSpecifier(IoSpecKind::Decimal, flags_.test(Flag::FmtOrNml),
      "FMT or NML");  // C1227
  CheckForRequiredSpecifier(IoSpecKind::Round, flags_.test(Flag::FmtOrNml),
      "FMT or NML");  // C1227
}

void IoChecker::SetSpecifier(IoSpecKind specKind) {
  if (stmt_ == IoStmtKind::None) {
    // FMT may appear on PRINT statements, which don't have any checks.
    // [IO]MSG and [IO]STAT parse symbols are shared with non-I/O statements.
    return;
  }
  // C1203, C1207, C1210, C1236, C1239, C1242, C1245
  if (specifierSet_.test(specKind)) {
    context_.Say("duplicate %s specifier"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str());
  }
  specifierSet_.set(specKind);
}

void IoChecker::CheckStringValue(IoSpecKind specKind, const std::string &value,
    const parser::CharBlock &source) const {
  static std::unordered_map<IoSpecKind, const std::set<std::string>> specValues{
      {IoSpecKind::Access, {"DIRECT", "SEQUENTIAL", "STREAM"}},
      {IoSpecKind::Action, {"READ", "READWRITE", "WRITE"}},
      {IoSpecKind::Advance, {"NO", "YES"}},
      {IoSpecKind::Asynchronous, {"NO", "YES"}},
      {IoSpecKind::Blank, {"NULL", "ZERO"}},
      {IoSpecKind::Decimal, {"COMMA", "POINT"}},
      {IoSpecKind::Delim, {"APOSTROPHE", "NONE", "QUOTE"}},
      {IoSpecKind::Encoding, {"DEFAULT", "UTF-8"}},
      {IoSpecKind::Form, {"FORMATTED", "UNFORMATTED"}},
      {IoSpecKind::Pad, {"NO", "YES"}},
      {IoSpecKind::Position, {"APPEND", "ASIS", "REWIND"}},
      {IoSpecKind::Round,
          {"COMPATIBLE", "DOWN", "NEAREST", "PROCESSOR_DEFINED", "UP", "ZERO"}},
      {IoSpecKind::Sign, {"PLUS", "PROCESSOR_DEFINED", "SUPPRESS"}},
      {IoSpecKind::Status,
          // Open values; Close values are {"DELETE", "KEEP"}.
          {"NEW", "OLD", "REPLACE", "SCRATCH", "UNKNOWN"}},
      {IoSpecKind::Convert, {"BIG_ENDIAN", "LITTLE_ENDIAN", "NATIVE"}},
      {IoSpecKind::Dispose, {"DELETE", "KEEP"}},
  };
  if (!specValues.at(specKind).count(parser::ToUpperCaseLetters(value))) {
    context_.Say(source, "invalid %s value '%s'"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str(),
        value.c_str());
  }
}

// CheckForRequiredSpecifier and CheckForProhibitedSpecifier functions
// need conditions to check, and string arguments to insert into a message.
// A IoSpecKind provides both an absence/presence condition and a string
// argument (its name).  A (condition, string) pair provides an arbitrary
// condition and an arbitrary string.

void IoChecker::CheckForRequiredSpecifier(IoSpecKind specKind) const {
  if (!specifierSet_.test(specKind)) {
    context_.Say("%s statement must have a %s specifier"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(stmt_)).c_str(),
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str());
  }
}

void IoChecker::CheckForRequiredSpecifier(
    bool condition, const std::string &s) const {
  if (!condition) {
    context_.Say("%s statement must have a %s specifier"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(stmt_)).c_str(),
        s.c_str());
  }
}

void IoChecker::CheckForRequiredSpecifier(
    IoSpecKind specKind1, IoSpecKind specKind2) const {
  if (specifierSet_.test(specKind1) && !specifierSet_.test(specKind2)) {
    context_.Say("if %s appears, %s must also appear"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(specKind1)).c_str(),
        parser::ToUpperCaseLetters(common::EnumToString(specKind2)).c_str());
  }
}

void IoChecker::CheckForRequiredSpecifier(
    IoSpecKind specKind, bool condition, const std::string &s) const {
  if (specifierSet_.test(specKind) && !condition) {
    context_.Say("if %s appears, %s must also appear"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str(),
        s.c_str());
  }
}

void IoChecker::CheckForRequiredSpecifier(
    bool condition, const std::string &s, IoSpecKind specKind) const {
  if (condition && !specifierSet_.test(specKind)) {
    context_.Say("if %s appears, %s must also appear"_err_en_US, s.c_str(),
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str());
  }
}

void IoChecker::CheckForRequiredSpecifier(bool condition1,
    const std::string &s1, bool condition2, const std::string &s2) const {
  if (condition1 && !condition2) {
    context_.Say(
        "if %s appears, %s must also appear"_err_en_US, s1.c_str(), s2.c_str());
  }
}

void IoChecker::CheckForProhibitedSpecifier(IoSpecKind specKind) const {
  if (specifierSet_.test(specKind)) {
    context_.Say("%s statement must not have a %s specifier"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(stmt_)).c_str(),
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str());
  }
}

void IoChecker::CheckForProhibitedSpecifier(
    IoSpecKind specKind1, IoSpecKind specKind2) const {
  if (specifierSet_.test(specKind1) && specifierSet_.test(specKind2)) {
    context_.Say("if %s appears, %s must not appear"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(specKind1)).c_str(),
        parser::ToUpperCaseLetters(common::EnumToString(specKind2)).c_str());
  }
}

void IoChecker::CheckForProhibitedSpecifier(
    IoSpecKind specKind, bool condition, const std::string &s) const {
  if (specifierSet_.test(specKind) && condition) {
    context_.Say("if %s appears, %s must not appear"_err_en_US,
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str(),
        s.c_str());
  }
}

void IoChecker::CheckForProhibitedSpecifier(
    bool condition, const std::string &s, IoSpecKind specKind) const {
  if (condition && specifierSet_.test(specKind)) {
    context_.Say("if %s appears, %s must not appear"_err_en_US, s.c_str(),
        parser::ToUpperCaseLetters(common::EnumToString(specKind)).c_str());
  }
}

}  // namespace Fortran::semantics