xref: /llvm-project/flang/lib/Semantics/check-io.cpp (revision aa128bb21ee37ce07b02043fde57914d60ff2097) 
1 //===-- lib/Semantics/check-io.cpp ----------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "check-io.h"
10 #include "definable.h"
11 #include "flang/Common/format.h"
12 #include "flang/Evaluate/tools.h"
13 #include "flang/Parser/tools.h"
14 #include "flang/Semantics/expression.h"
15 #include "flang/Semantics/tools.h"
16 #include <unordered_map>
17 
18 namespace Fortran::semantics {
19 
20 // TODO: C1234, C1235 -- defined I/O constraints
21 
22 class FormatErrorReporter {
23 public:
24   FormatErrorReporter(SemanticsContext &context,
25       const parser::CharBlock &formatCharBlock, int errorAllowance = 3)
26       : context_{context}, formatCharBlock_{formatCharBlock},
27         errorAllowance_{errorAllowance} {}
28 
29   bool Say(const common::FormatMessage &);
30 
31 private:
32   SemanticsContext &context_;
33   const parser::CharBlock &formatCharBlock_;
34   int errorAllowance_; // initialized to maximum number of errors to report
35 };
36 
37 bool FormatErrorReporter::Say(const common::FormatMessage &msg) {
38   if (!msg.isError && !context_.warnOnNonstandardUsage()) {
39     return false;
40   }
41   parser::MessageFormattedText text{
42       parser::MessageFixedText{msg.text, strlen(msg.text),
43           msg.isError ? parser::Severity::Error : parser::Severity::Warning},
44       msg.arg};
45   if (formatCharBlock_.size()) {
46     // The input format is a folded expression.  Error markers span the full
47     // original unfolded expression in formatCharBlock_.
48     context_.Say(formatCharBlock_, text);
49   } else {
50     // The input format is a source expression.  Error markers have an offset
51     // and length relative to the beginning of formatCharBlock_.
52     parser::CharBlock messageCharBlock{
53         parser::CharBlock(formatCharBlock_.begin() + msg.offset, msg.length)};
54     context_.Say(messageCharBlock, text);
55   }
56   return msg.isError && --errorAllowance_ <= 0;
57 }
58 
59 void IoChecker::Enter(
60     const parser::Statement<common::Indirection<parser::FormatStmt>> &stmt) {
61   if (!stmt.label) {
62     context_.Say("Format statement must be labeled"_err_en_US); // C1301
63   }
64   const char *formatStart{static_cast<const char *>(
65       std::memchr(stmt.source.begin(), '(', stmt.source.size()))};
66   parser::CharBlock reporterCharBlock{formatStart, static_cast<std::size_t>(0)};
67   FormatErrorReporter reporter{context_, reporterCharBlock};
68   auto reporterWrapper{[&](const auto &msg) { return reporter.Say(msg); }};
69   switch (context_.GetDefaultKind(TypeCategory::Character)) {
70   case 1: {
71     common::FormatValidator<char> validator{formatStart,
72         stmt.source.size() - (formatStart - stmt.source.begin()),
73         reporterWrapper};
74     validator.Check();
75     break;
76   }
77   case 2: { // TODO: Get this to work.
78     common::FormatValidator<char16_t> validator{
79         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
80     validator.Check();
81     break;
82   }
83   case 4: { // TODO: Get this to work.
84     common::FormatValidator<char32_t> validator{
85         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
86     validator.Check();
87     break;
88   }
89   default:
90     CRASH_NO_CASE;
91   }
92 }
93 
94 void IoChecker::Enter(const parser::ConnectSpec &spec) {
95   // ConnectSpec context FileNameExpr
96   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
97     SetSpecifier(IoSpecKind::File);
98   }
99 }
100 
101 // Ignore trailing spaces (12.5.6.2 p1) and convert to upper case
102 static std::string Normalize(const std::string &value) {
103   auto upper{parser::ToUpperCaseLetters(value)};
104   std::size_t lastNonBlank{upper.find_last_not_of(" ")};
105   upper.resize(lastNonBlank == std::string::npos ? 0 : lastNonBlank + 1);
106   return upper;
107 }
108 
109 void IoChecker::Enter(const parser::ConnectSpec::CharExpr &spec) {
110   IoSpecKind specKind{};
111   using ParseKind = parser::ConnectSpec::CharExpr::Kind;
112   switch (std::get<ParseKind>(spec.t)) {
113   case ParseKind::Access:
114     specKind = IoSpecKind::Access;
115     break;
116   case ParseKind::Action:
117     specKind = IoSpecKind::Action;
118     break;
119   case ParseKind::Asynchronous:
120     specKind = IoSpecKind::Asynchronous;
121     break;
122   case ParseKind::Blank:
123     specKind = IoSpecKind::Blank;
124     break;
125   case ParseKind::Decimal:
126     specKind = IoSpecKind::Decimal;
127     break;
128   case ParseKind::Delim:
129     specKind = IoSpecKind::Delim;
130     break;
131   case ParseKind::Encoding:
132     specKind = IoSpecKind::Encoding;
133     break;
134   case ParseKind::Form:
135     specKind = IoSpecKind::Form;
136     break;
137   case ParseKind::Pad:
138     specKind = IoSpecKind::Pad;
139     break;
140   case ParseKind::Position:
141     specKind = IoSpecKind::Position;
142     break;
143   case ParseKind::Round:
144     specKind = IoSpecKind::Round;
145     break;
146   case ParseKind::Sign:
147     specKind = IoSpecKind::Sign;
148     break;
149   case ParseKind::Carriagecontrol:
150     specKind = IoSpecKind::Carriagecontrol;
151     break;
152   case ParseKind::Convert:
153     specKind = IoSpecKind::Convert;
154     break;
155   case ParseKind::Dispose:
156     specKind = IoSpecKind::Dispose;
157     break;
158   }
159   SetSpecifier(specKind);
160   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
161           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
162     std::string s{Normalize(*charConst)};
163     if (specKind == IoSpecKind::Access) {
164       flags_.set(Flag::KnownAccess);
165       flags_.set(Flag::AccessDirect, s == "DIRECT");
166       flags_.set(Flag::AccessStream, s == "STREAM");
167     }
168     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
169     if (specKind == IoSpecKind::Carriagecontrol &&
170         (s == "FORTRAN" || s == "NONE")) {
171       context_.Say(parser::FindSourceLocation(spec),
172           "Unimplemented %s value '%s'"_err_en_US,
173           parser::ToUpperCaseLetters(common::EnumToString(specKind)),
174           *charConst);
175     }
176   }
177 }
178 
179 void IoChecker::Enter(const parser::ConnectSpec::Newunit &var) {
180   CheckForDefinableVariable(var, "NEWUNIT");
181   SetSpecifier(IoSpecKind::Newunit);
182 }
183 
184 void IoChecker::Enter(const parser::ConnectSpec::Recl &spec) {
185   SetSpecifier(IoSpecKind::Recl);
186   if (const std::optional<std::int64_t> recl{
187           GetConstExpr<std::int64_t>(spec)}) {
188     if (*recl <= 0) {
189       context_.Say(parser::FindSourceLocation(spec),
190           "RECL value (%jd) must be positive"_err_en_US,
191           *recl); // 12.5.6.15
192     }
193   }
194 }
195 
196 void IoChecker::Enter(const parser::EndLabel &) {
197   SetSpecifier(IoSpecKind::End);
198 }
199 
200 void IoChecker::Enter(const parser::EorLabel &) {
201   SetSpecifier(IoSpecKind::Eor);
202 }
203 
204 void IoChecker::Enter(const parser::ErrLabel &) {
205   SetSpecifier(IoSpecKind::Err);
206 }
207 
208 void IoChecker::Enter(const parser::FileUnitNumber &) {
209   SetSpecifier(IoSpecKind::Unit);
210   flags_.set(Flag::NumberUnit);
211 }
212 
213 void IoChecker::Enter(const parser::Format &spec) {
214   SetSpecifier(IoSpecKind::Fmt);
215   flags_.set(Flag::FmtOrNml);
216   common::visit(
217       common::visitors{
218           [&](const parser::Label &) { flags_.set(Flag::LabelFmt); },
219           [&](const parser::Star &) { flags_.set(Flag::StarFmt); },
220           [&](const parser::Expr &format) {
221             const SomeExpr *expr{GetExpr(context_, format)};
222             if (!expr) {
223               return;
224             }
225             auto type{expr->GetType()};
226             if (type && type->category() == TypeCategory::Integer &&
227                 type->kind() ==
228                     context_.defaultKinds().GetDefaultKind(type->category()) &&
229                 expr->Rank() == 0) {
230               flags_.set(Flag::AssignFmt);
231               if (!IsVariable(*expr)) {
232                 context_.Say(format.source,
233                     "Assigned format label must be a scalar variable"_err_en_US);
234               } else if (context_.ShouldWarn(common::LanguageFeature::Assign)) {
235                 context_.Say(format.source,
236                     "Assigned format labels are deprecated"_port_en_US);
237               }
238               return;
239             }
240             if (type && type->category() != TypeCategory::Character &&
241                 (type->category() != TypeCategory::Integer ||
242                     expr->Rank() > 0) &&
243                 context_.IsEnabled(
244                     common::LanguageFeature::NonCharacterFormat)) {
245               // Legacy extension: using non-character variables, typically
246               // DATA-initialized with Hollerith, as format expressions.
247               if (context_.ShouldWarn(
248                       common::LanguageFeature::NonCharacterFormat)) {
249                 context_.Say(format.source,
250                     "Non-character format expression is not standard"_port_en_US);
251               }
252             } else if (!type ||
253                 type->kind() !=
254                     context_.defaultKinds().GetDefaultKind(type->category())) {
255               context_.Say(format.source,
256                   "Format expression must be default character or default scalar integer"_err_en_US);
257               return;
258             }
259             flags_.set(Flag::CharFmt);
260             const std::optional<std::string> constantFormat{
261                 GetConstExpr<std::string>(format)};
262             if (!constantFormat) {
263               return;
264             }
265             // validate constant format -- 12.6.2.2
266             bool isFolded{constantFormat->size() != format.source.size() - 2};
267             parser::CharBlock reporterCharBlock{isFolded
268                     ? parser::CharBlock{format.source}
269                     : parser::CharBlock{format.source.begin() + 1,
270                           static_cast<std::size_t>(0)}};
271             FormatErrorReporter reporter{context_, reporterCharBlock};
272             auto reporterWrapper{
273                 [&](const auto &msg) { return reporter.Say(msg); }};
274             switch (context_.GetDefaultKind(TypeCategory::Character)) {
275             case 1: {
276               common::FormatValidator<char> validator{constantFormat->c_str(),
277                   constantFormat->length(), reporterWrapper, stmt_};
278               validator.Check();
279               break;
280             }
281             case 2: {
282               // TODO: Get this to work.  (Maybe combine with earlier instance?)
283               common::FormatValidator<char16_t> validator{
284                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
285               validator.Check();
286               break;
287             }
288             case 4: {
289               // TODO: Get this to work.  (Maybe combine with earlier instance?)
290               common::FormatValidator<char32_t> validator{
291                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
292               validator.Check();
293               break;
294             }
295             default:
296               CRASH_NO_CASE;
297             }
298           },
299       },
300       spec.u);
301 }
302 
303 void IoChecker::Enter(const parser::IdExpr &) { SetSpecifier(IoSpecKind::Id); }
304 
305 void IoChecker::Enter(const parser::IdVariable &spec) {
306   SetSpecifier(IoSpecKind::Id);
307   const auto *expr{GetExpr(context_, spec)};
308   if (!expr || !expr->GetType()) {
309     return;
310   }
311   CheckForDefinableVariable(spec, "ID");
312   int kind{expr->GetType()->kind()};
313   int defaultKind{context_.GetDefaultKind(TypeCategory::Integer)};
314   if (kind < defaultKind) {
315     context_.Say(
316         "ID kind (%d) is smaller than default INTEGER kind (%d)"_err_en_US,
317         std::move(kind), std::move(defaultKind)); // C1229
318   }
319 }
320 
321 void IoChecker::Enter(const parser::InputItem &spec) {
322   flags_.set(Flag::DataList);
323   const parser::Variable *var{std::get_if<parser::Variable>(&spec.u)};
324   if (!var) {
325     return;
326   }
327   CheckForDefinableVariable(*var, "Input");
328   if (auto expr{AnalyzeExpr(context_, *var)}) {
329     CheckForBadIoType(*expr,
330         flags_.test(Flag::FmtOrNml) ? GenericKind::DefinedIo::ReadFormatted
331                                     : GenericKind::DefinedIo::ReadUnformatted,
332         var->GetSource());
333   }
334 }
335 
336 void IoChecker::Enter(const parser::InquireSpec &spec) {
337   // InquireSpec context FileNameExpr
338   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
339     SetSpecifier(IoSpecKind::File);
340   }
341 }
342 
343 void IoChecker::Enter(const parser::InquireSpec::CharVar &spec) {
344   IoSpecKind specKind{};
345   using ParseKind = parser::InquireSpec::CharVar::Kind;
346   switch (std::get<ParseKind>(spec.t)) {
347   case ParseKind::Access:
348     specKind = IoSpecKind::Access;
349     break;
350   case ParseKind::Action:
351     specKind = IoSpecKind::Action;
352     break;
353   case ParseKind::Asynchronous:
354     specKind = IoSpecKind::Asynchronous;
355     break;
356   case ParseKind::Blank:
357     specKind = IoSpecKind::Blank;
358     break;
359   case ParseKind::Decimal:
360     specKind = IoSpecKind::Decimal;
361     break;
362   case ParseKind::Delim:
363     specKind = IoSpecKind::Delim;
364     break;
365   case ParseKind::Direct:
366     specKind = IoSpecKind::Direct;
367     break;
368   case ParseKind::Encoding:
369     specKind = IoSpecKind::Encoding;
370     break;
371   case ParseKind::Form:
372     specKind = IoSpecKind::Form;
373     break;
374   case ParseKind::Formatted:
375     specKind = IoSpecKind::Formatted;
376     break;
377   case ParseKind::Iomsg:
378     specKind = IoSpecKind::Iomsg;
379     break;
380   case ParseKind::Name:
381     specKind = IoSpecKind::Name;
382     break;
383   case ParseKind::Pad:
384     specKind = IoSpecKind::Pad;
385     break;
386   case ParseKind::Position:
387     specKind = IoSpecKind::Position;
388     break;
389   case ParseKind::Read:
390     specKind = IoSpecKind::Read;
391     break;
392   case ParseKind::Readwrite:
393     specKind = IoSpecKind::Readwrite;
394     break;
395   case ParseKind::Round:
396     specKind = IoSpecKind::Round;
397     break;
398   case ParseKind::Sequential:
399     specKind = IoSpecKind::Sequential;
400     break;
401   case ParseKind::Sign:
402     specKind = IoSpecKind::Sign;
403     break;
404   case ParseKind::Status:
405     specKind = IoSpecKind::Status;
406     break;
407   case ParseKind::Stream:
408     specKind = IoSpecKind::Stream;
409     break;
410   case ParseKind::Unformatted:
411     specKind = IoSpecKind::Unformatted;
412     break;
413   case ParseKind::Write:
414     specKind = IoSpecKind::Write;
415     break;
416   case ParseKind::Carriagecontrol:
417     specKind = IoSpecKind::Carriagecontrol;
418     break;
419   case ParseKind::Convert:
420     specKind = IoSpecKind::Convert;
421     break;
422   case ParseKind::Dispose:
423     specKind = IoSpecKind::Dispose;
424     break;
425   }
426   CheckForDefinableVariable(std::get<parser::ScalarDefaultCharVariable>(spec.t),
427       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
428   SetSpecifier(specKind);
429 }
430 
431 void IoChecker::Enter(const parser::InquireSpec::IntVar &spec) {
432   IoSpecKind specKind{};
433   using ParseKind = parser::InquireSpec::IntVar::Kind;
434   switch (std::get<parser::InquireSpec::IntVar::Kind>(spec.t)) {
435   case ParseKind::Iostat:
436     specKind = IoSpecKind::Iostat;
437     break;
438   case ParseKind::Nextrec:
439     specKind = IoSpecKind::Nextrec;
440     break;
441   case ParseKind::Number:
442     specKind = IoSpecKind::Number;
443     break;
444   case ParseKind::Pos:
445     specKind = IoSpecKind::Pos;
446     break;
447   case ParseKind::Recl:
448     specKind = IoSpecKind::Recl;
449     break;
450   case ParseKind::Size:
451     specKind = IoSpecKind::Size;
452     break;
453   }
454   CheckForDefinableVariable(std::get<parser::ScalarIntVariable>(spec.t),
455       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
456   SetSpecifier(specKind);
457 }
458 
459 void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
460   IoSpecKind specKind{};
461   using ParseKind = parser::InquireSpec::LogVar::Kind;
462   switch (std::get<parser::InquireSpec::LogVar::Kind>(spec.t)) {
463   case ParseKind::Exist:
464     specKind = IoSpecKind::Exist;
465     break;
466   case ParseKind::Named:
467     specKind = IoSpecKind::Named;
468     break;
469   case ParseKind::Opened:
470     specKind = IoSpecKind::Opened;
471     break;
472   case ParseKind::Pending:
473     specKind = IoSpecKind::Pending;
474     break;
475   }
476   SetSpecifier(specKind);
477 }
478 
479 void IoChecker::Enter(const parser::IoControlSpec &spec) {
480   // IoControlSpec context Name
481   flags_.set(Flag::IoControlList);
482   if (std::holds_alternative<parser::Name>(spec.u)) {
483     SetSpecifier(IoSpecKind::Nml);
484     flags_.set(Flag::FmtOrNml);
485   }
486 }
487 
488 void IoChecker::Enter(const parser::IoControlSpec::Asynchronous &spec) {
489   SetSpecifier(IoSpecKind::Asynchronous);
490   if (const std::optional<std::string> charConst{
491           GetConstExpr<std::string>(spec)}) {
492     flags_.set(Flag::AsynchronousYes, Normalize(*charConst) == "YES");
493     CheckStringValue(IoSpecKind::Asynchronous, *charConst,
494         parser::FindSourceLocation(spec)); // C1223
495   }
496 }
497 
498 void IoChecker::Enter(const parser::IoControlSpec::CharExpr &spec) {
499   IoSpecKind specKind{};
500   using ParseKind = parser::IoControlSpec::CharExpr::Kind;
501   switch (std::get<ParseKind>(spec.t)) {
502   case ParseKind::Advance:
503     specKind = IoSpecKind::Advance;
504     break;
505   case ParseKind::Blank:
506     specKind = IoSpecKind::Blank;
507     break;
508   case ParseKind::Decimal:
509     specKind = IoSpecKind::Decimal;
510     break;
511   case ParseKind::Delim:
512     specKind = IoSpecKind::Delim;
513     break;
514   case ParseKind::Pad:
515     specKind = IoSpecKind::Pad;
516     break;
517   case ParseKind::Round:
518     specKind = IoSpecKind::Round;
519     break;
520   case ParseKind::Sign:
521     specKind = IoSpecKind::Sign;
522     break;
523   }
524   SetSpecifier(specKind);
525   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
526           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
527     if (specKind == IoSpecKind::Advance) {
528       flags_.set(Flag::AdvanceYes, Normalize(*charConst) == "YES");
529     }
530     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
531   }
532 }
533 
534 void IoChecker::Enter(const parser::IoControlSpec::Pos &) {
535   SetSpecifier(IoSpecKind::Pos);
536 }
537 
538 void IoChecker::Enter(const parser::IoControlSpec::Rec &) {
539   SetSpecifier(IoSpecKind::Rec);
540 }
541 
542 void IoChecker::Enter(const parser::IoControlSpec::Size &var) {
543   CheckForDefinableVariable(var, "SIZE");
544   SetSpecifier(IoSpecKind::Size);
545 }
546 
547 void IoChecker::Enter(const parser::IoUnit &spec) {
548   if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
549     // Only now after generic resolution can it be known whether a function
550     // call appearing as UNIT=f() is an integer scalar external unit number
551     // or a character pointer for internal I/O.
552     const auto *expr{GetExpr(context_, *var)};
553     std::optional<evaluate::DynamicType> dyType;
554     if (expr) {
555       dyType = expr->GetType();
556     }
557     if (dyType && dyType->category() == TypeCategory::Integer) {
558       if (expr->Rank() != 0) {
559         context_.Say(parser::FindSourceLocation(*var),
560             "I/O unit number must be scalar"_err_en_US);
561       }
562       // In the case of an integer unit number variable, rewrite the parse
563       // tree as if the unit had been parsed as a FileUnitNumber in order
564       // to ease lowering.
565       auto &mutableSpec{const_cast<parser::IoUnit &>(spec)};
566       auto &mutableVar{std::get<parser::Variable>(mutableSpec.u)};
567       auto source{mutableVar.GetSource()};
568       auto typedExpr{std::move(mutableVar.typedExpr)};
569       auto newExpr{common::visit(
570           [](auto &&indirection) {
571             return parser::Expr{std::move(indirection)};
572           },
573           std::move(mutableVar.u))};
574       newExpr.source = source;
575       newExpr.typedExpr = std::move(typedExpr);
576       mutableSpec.u = parser::FileUnitNumber{
577           parser::ScalarIntExpr{parser::IntExpr{std::move(newExpr)}}};
578     } else if (!dyType || dyType->category() != TypeCategory::Character) {
579       SetSpecifier(IoSpecKind::Unit);
580       context_.Say(parser::FindSourceLocation(*var),
581           "I/O unit must be a character variable or a scalar integer expression"_err_en_US);
582     } else { // CHARACTER variable (internal I/O)
583       if (stmt_ == IoStmtKind::Write) {
584         CheckForDefinableVariable(*var, "Internal file");
585       }
586       if (HasVectorSubscript(*expr)) {
587         context_.Say(parser::FindSourceLocation(*var), // C1201
588             "Internal file must not have a vector subscript"_err_en_US);
589       }
590       SetSpecifier(IoSpecKind::Unit);
591       flags_.set(Flag::InternalUnit);
592     }
593   } else if (std::get_if<parser::Star>(&spec.u)) {
594     SetSpecifier(IoSpecKind::Unit);
595     flags_.set(Flag::StarUnit);
596   }
597 }
598 
599 void IoChecker::Enter(const parser::MsgVariable &var) {
600   if (stmt_ == IoStmtKind::None) {
601     // allocate, deallocate, image control
602     CheckForDefinableVariable(var, "ERRMSG");
603     return;
604   }
605   CheckForDefinableVariable(var, "IOMSG");
606   SetSpecifier(IoSpecKind::Iomsg);
607 }
608 
609 void IoChecker::Enter(const parser::OutputItem &item) {
610   flags_.set(Flag::DataList);
611   if (const auto *x{std::get_if<parser::Expr>(&item.u)}) {
612     if (const auto *expr{GetExpr(context_, *x)}) {
613       if (evaluate::IsBOZLiteral(*expr)) {
614         context_.Say(parser::FindSourceLocation(*x), // C7109
615             "Output item must not be a BOZ literal constant"_err_en_US);
616       } else if (IsProcedure(*expr)) {
617         context_.Say(parser::FindSourceLocation(*x),
618             "Output item must not be a procedure"_err_en_US); // C1233
619       }
620       CheckForBadIoType(*expr,
621           flags_.test(Flag::FmtOrNml)
622               ? GenericKind::DefinedIo::WriteFormatted
623               : GenericKind::DefinedIo::WriteUnformatted,
624           parser::FindSourceLocation(item));
625     }
626   }
627 }
628 
629 void IoChecker::Enter(const parser::StatusExpr &spec) {
630   SetSpecifier(IoSpecKind::Status);
631   if (const std::optional<std::string> charConst{
632           GetConstExpr<std::string>(spec)}) {
633     // Status values for Open and Close are different.
634     std::string s{Normalize(*charConst)};
635     if (stmt_ == IoStmtKind::Open) {
636       flags_.set(Flag::KnownStatus);
637       flags_.set(Flag::StatusNew, s == "NEW");
638       flags_.set(Flag::StatusReplace, s == "REPLACE");
639       flags_.set(Flag::StatusScratch, s == "SCRATCH");
640       // CheckStringValue compares for OPEN Status string values.
641       CheckStringValue(
642           IoSpecKind::Status, *charConst, parser::FindSourceLocation(spec));
643       return;
644     }
645     CHECK(stmt_ == IoStmtKind::Close);
646     if (s != "DELETE" && s != "KEEP") {
647       context_.Say(parser::FindSourceLocation(spec),
648           "Invalid STATUS value '%s'"_err_en_US, *charConst);
649     }
650   }
651 }
652 
653 void IoChecker::Enter(const parser::StatVariable &var) {
654   if (stmt_ == IoStmtKind::None) {
655     // allocate, deallocate, image control
656     CheckForDefinableVariable(var, "STAT");
657     return;
658   }
659   CheckForDefinableVariable(var, "IOSTAT");
660   SetSpecifier(IoSpecKind::Iostat);
661 }
662 
663 void IoChecker::Leave(const parser::BackspaceStmt &) {
664   CheckForPureSubprogram();
665   CheckForRequiredSpecifier(
666       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
667   Done();
668 }
669 
670 void IoChecker::Leave(const parser::CloseStmt &) {
671   CheckForPureSubprogram();
672   CheckForRequiredSpecifier(
673       flags_.test(Flag::NumberUnit), "UNIT number"); // C1208
674   Done();
675 }
676 
677 void IoChecker::Leave(const parser::EndfileStmt &) {
678   CheckForPureSubprogram();
679   CheckForRequiredSpecifier(
680       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
681   Done();
682 }
683 
684 void IoChecker::Leave(const parser::FlushStmt &) {
685   CheckForPureSubprogram();
686   CheckForRequiredSpecifier(
687       flags_.test(Flag::NumberUnit), "UNIT number"); // C1243
688   Done();
689 }
690 
691 void IoChecker::Leave(const parser::InquireStmt &stmt) {
692   if (std::get_if<std::list<parser::InquireSpec>>(&stmt.u)) {
693     CheckForPureSubprogram();
694     // Inquire by unit or by file (vs. by output list).
695     CheckForRequiredSpecifier(
696         flags_.test(Flag::NumberUnit) || specifierSet_.test(IoSpecKind::File),
697         "UNIT number or FILE"); // C1246
698     CheckForProhibitedSpecifier(IoSpecKind::File, IoSpecKind::Unit); // C1246
699     CheckForRequiredSpecifier(IoSpecKind::Id, IoSpecKind::Pending); // C1248
700   }
701   Done();
702 }
703 
704 void IoChecker::Leave(const parser::OpenStmt &) {
705   CheckForPureSubprogram();
706   CheckForRequiredSpecifier(specifierSet_.test(IoSpecKind::Unit) ||
707           specifierSet_.test(IoSpecKind::Newunit),
708       "UNIT or NEWUNIT"); // C1204, C1205
709   CheckForProhibitedSpecifier(
710       IoSpecKind::Newunit, IoSpecKind::Unit); // C1204, C1205
711   CheckForRequiredSpecifier(flags_.test(Flag::StatusNew), "STATUS='NEW'",
712       IoSpecKind::File); // 12.5.6.10
713   CheckForRequiredSpecifier(flags_.test(Flag::StatusReplace),
714       "STATUS='REPLACE'", IoSpecKind::File); // 12.5.6.10
715   CheckForProhibitedSpecifier(flags_.test(Flag::StatusScratch),
716       "STATUS='SCRATCH'", IoSpecKind::File); // 12.5.6.10
717   if (flags_.test(Flag::KnownStatus)) {
718     CheckForRequiredSpecifier(IoSpecKind::Newunit,
719         specifierSet_.test(IoSpecKind::File) ||
720             flags_.test(Flag::StatusScratch),
721         "FILE or STATUS='SCRATCH'"); // 12.5.6.12
722   } else {
723     CheckForRequiredSpecifier(IoSpecKind::Newunit,
724         specifierSet_.test(IoSpecKind::File) ||
725             specifierSet_.test(IoSpecKind::Status),
726         "FILE or STATUS"); // 12.5.6.12
727   }
728   if (flags_.test(Flag::KnownAccess)) {
729     CheckForRequiredSpecifier(flags_.test(Flag::AccessDirect),
730         "ACCESS='DIRECT'", IoSpecKind::Recl); // 12.5.6.15
731     CheckForProhibitedSpecifier(flags_.test(Flag::AccessStream),
732         "STATUS='STREAM'", IoSpecKind::Recl); // 12.5.6.15
733   }
734   Done();
735 }
736 
737 void IoChecker::Leave(const parser::PrintStmt &) {
738   CheckForPureSubprogram();
739   Done();
740 }
741 
742 static const parser::Name *FindNamelist(
743     const std::list<parser::IoControlSpec> &controls) {
744   for (const auto &control : controls) {
745     if (const parser::Name * namelist{std::get_if<parser::Name>(&control.u)}) {
746       if (namelist->symbol &&
747           namelist->symbol->GetUltimate().has<NamelistDetails>()) {
748         return namelist;
749       }
750     }
751   }
752   return nullptr;
753 }
754 
755 static void CheckForDoVariable(
756     const parser::ReadStmt &readStmt, SemanticsContext &context) {
757   const std::list<parser::InputItem> &items{readStmt.items};
758   for (const auto &item : items) {
759     if (const parser::Variable *
760         variable{std::get_if<parser::Variable>(&item.u)}) {
761       context.CheckIndexVarRedefine(*variable);
762     }
763   }
764 }
765 
766 void IoChecker::Leave(const parser::ReadStmt &readStmt) {
767   if (!flags_.test(Flag::InternalUnit)) {
768     CheckForPureSubprogram();
769   }
770   if (const parser::Name * namelist{FindNamelist(readStmt.controls)}) {
771     if (namelist->symbol) {
772       CheckNamelist(*namelist->symbol, GenericKind::DefinedIo::ReadFormatted,
773           namelist->source);
774     }
775   }
776   CheckForDoVariable(readStmt, context_);
777   if (!flags_.test(Flag::IoControlList)) {
778     Done();
779     return;
780   }
781   LeaveReadWrite();
782   CheckForProhibitedSpecifier(IoSpecKind::Delim); // C1212
783   CheckForProhibitedSpecifier(IoSpecKind::Sign); // C1212
784   CheckForProhibitedSpecifier(IoSpecKind::Rec, IoSpecKind::End); // C1220
785   CheckForRequiredSpecifier(IoSpecKind::Eor,
786       specifierSet_.test(IoSpecKind::Advance) && !flags_.test(Flag::AdvanceYes),
787       "ADVANCE with value 'NO'"); // C1222 + 12.6.2.1p2
788   CheckForRequiredSpecifier(IoSpecKind::Blank, flags_.test(Flag::FmtOrNml),
789       "FMT or NML"); // C1227
790   CheckForRequiredSpecifier(
791       IoSpecKind::Pad, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
792   Done();
793 }
794 
795 void IoChecker::Leave(const parser::RewindStmt &) {
796   CheckForRequiredSpecifier(
797       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
798   CheckForPureSubprogram();
799   Done();
800 }
801 
802 void IoChecker::Leave(const parser::WaitStmt &) {
803   CheckForRequiredSpecifier(
804       flags_.test(Flag::NumberUnit), "UNIT number"); // C1237
805   CheckForPureSubprogram();
806   Done();
807 }
808 
809 void IoChecker::Leave(const parser::WriteStmt &writeStmt) {
810   if (!flags_.test(Flag::InternalUnit)) {
811     CheckForPureSubprogram();
812   }
813   if (const parser::Name * namelist{FindNamelist(writeStmt.controls)}) {
814     if (namelist->symbol) {
815       CheckNamelist(*namelist->symbol, GenericKind::DefinedIo::WriteFormatted,
816           namelist->source);
817     }
818   }
819   LeaveReadWrite();
820   CheckForProhibitedSpecifier(IoSpecKind::Blank); // C1213
821   CheckForProhibitedSpecifier(IoSpecKind::End); // C1213
822   CheckForProhibitedSpecifier(IoSpecKind::Eor); // C1213
823   CheckForProhibitedSpecifier(IoSpecKind::Pad); // C1213
824   CheckForProhibitedSpecifier(IoSpecKind::Size); // C1213
825   CheckForRequiredSpecifier(
826       IoSpecKind::Sign, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
827   CheckForRequiredSpecifier(IoSpecKind::Delim,
828       flags_.test(Flag::StarFmt) || specifierSet_.test(IoSpecKind::Nml),
829       "FMT=* or NML"); // C1228
830   Done();
831 }
832 
833 void IoChecker::LeaveReadWrite() const {
834   CheckForRequiredSpecifier(IoSpecKind::Unit); // C1211
835   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Rec); // C1216
836   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Fmt); // C1216
837   CheckForProhibitedSpecifier(
838       IoSpecKind::Nml, flags_.test(Flag::DataList), "a data list"); // C1216
839   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
840       "UNIT=internal-file", IoSpecKind::Pos); // C1219
841   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
842       "UNIT=internal-file", IoSpecKind::Rec); // C1219
843   CheckForProhibitedSpecifier(
844       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Pos); // C1219
845   CheckForProhibitedSpecifier(
846       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Rec); // C1219
847   CheckForProhibitedSpecifier(
848       IoSpecKind::Rec, flags_.test(Flag::StarFmt), "FMT=*"); // C1220
849   CheckForRequiredSpecifier(IoSpecKind::Advance,
850       flags_.test(Flag::CharFmt) || flags_.test(Flag::LabelFmt) ||
851           flags_.test(Flag::AssignFmt),
852       "an explicit format"); // C1221
853   CheckForProhibitedSpecifier(IoSpecKind::Advance,
854       flags_.test(Flag::InternalUnit), "UNIT=internal-file"); // C1221
855   CheckForRequiredSpecifier(flags_.test(Flag::AsynchronousYes),
856       "ASYNCHRONOUS='YES'", flags_.test(Flag::NumberUnit),
857       "UNIT=number"); // C1224
858   CheckForRequiredSpecifier(IoSpecKind::Id, flags_.test(Flag::AsynchronousYes),
859       "ASYNCHRONOUS='YES'"); // C1225
860   CheckForProhibitedSpecifier(IoSpecKind::Pos, IoSpecKind::Rec); // C1226
861   CheckForRequiredSpecifier(IoSpecKind::Decimal, flags_.test(Flag::FmtOrNml),
862       "FMT or NML"); // C1227
863   CheckForRequiredSpecifier(IoSpecKind::Round, flags_.test(Flag::FmtOrNml),
864       "FMT or NML"); // C1227
865 }
866 
867 void IoChecker::SetSpecifier(IoSpecKind specKind) {
868   if (stmt_ == IoStmtKind::None) {
869     // FMT may appear on PRINT statements, which don't have any checks.
870     // [IO]MSG and [IO]STAT parse symbols are shared with non-I/O statements.
871     return;
872   }
873   // C1203, C1207, C1210, C1236, C1239, C1242, C1245
874   if (specifierSet_.test(specKind)) {
875     context_.Say("Duplicate %s specifier"_err_en_US,
876         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
877   }
878   specifierSet_.set(specKind);
879 }
880 
881 void IoChecker::CheckStringValue(IoSpecKind specKind, const std::string &value,
882     const parser::CharBlock &source) const {
883   static std::unordered_map<IoSpecKind, const std::set<std::string>> specValues{
884       {IoSpecKind::Access, {"DIRECT", "SEQUENTIAL", "STREAM"}},
885       {IoSpecKind::Action, {"READ", "READWRITE", "WRITE"}},
886       {IoSpecKind::Advance, {"NO", "YES"}},
887       {IoSpecKind::Asynchronous, {"NO", "YES"}},
888       {IoSpecKind::Blank, {"NULL", "ZERO"}},
889       {IoSpecKind::Decimal, {"COMMA", "POINT"}},
890       {IoSpecKind::Delim, {"APOSTROPHE", "NONE", "QUOTE"}},
891       {IoSpecKind::Encoding, {"DEFAULT", "UTF-8"}},
892       {IoSpecKind::Form, {"FORMATTED", "UNFORMATTED"}},
893       {IoSpecKind::Pad, {"NO", "YES"}},
894       {IoSpecKind::Position, {"APPEND", "ASIS", "REWIND"}},
895       {IoSpecKind::Round,
896           {"COMPATIBLE", "DOWN", "NEAREST", "PROCESSOR_DEFINED", "UP", "ZERO"}},
897       {IoSpecKind::Sign, {"PLUS", "PROCESSOR_DEFINED", "SUPPRESS"}},
898       {IoSpecKind::Status,
899           // Open values; Close values are {"DELETE", "KEEP"}.
900           {"NEW", "OLD", "REPLACE", "SCRATCH", "UNKNOWN"}},
901       {IoSpecKind::Carriagecontrol, {"LIST", "FORTRAN", "NONE"}},
902       {IoSpecKind::Convert, {"BIG_ENDIAN", "LITTLE_ENDIAN", "NATIVE"}},
903       {IoSpecKind::Dispose, {"DELETE", "KEEP"}},
904   };
905   auto upper{Normalize(value)};
906   if (specValues.at(specKind).count(upper) == 0) {
907     if (specKind == IoSpecKind::Access && upper == "APPEND") {
908       if (context_.languageFeatures().ShouldWarn(
909               common::LanguageFeature::OpenAccessAppend)) {
910         context_.Say(source,
911             "ACCESS='%s' interpreted as POSITION='%s'"_port_en_US, value,
912             upper);
913       }
914     } else {
915       context_.Say(source, "Invalid %s value '%s'"_err_en_US,
916           parser::ToUpperCaseLetters(common::EnumToString(specKind)), value);
917     }
918   }
919 }
920 
921 // CheckForRequiredSpecifier and CheckForProhibitedSpecifier functions
922 // need conditions to check, and string arguments to insert into a message.
923 // An IoSpecKind provides both an absence/presence condition and a string
924 // argument (its name).  A (condition, string) pair provides an arbitrary
925 // condition and an arbitrary string.
926 
927 void IoChecker::CheckForRequiredSpecifier(IoSpecKind specKind) const {
928   if (!specifierSet_.test(specKind)) {
929     context_.Say("%s statement must have a %s specifier"_err_en_US,
930         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
931         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
932   }
933 }
934 
935 void IoChecker::CheckForRequiredSpecifier(
936     bool condition, const std::string &s) const {
937   if (!condition) {
938     context_.Say("%s statement must have a %s specifier"_err_en_US,
939         parser::ToUpperCaseLetters(common::EnumToString(stmt_)), s);
940   }
941 }
942 
943 void IoChecker::CheckForRequiredSpecifier(
944     IoSpecKind specKind1, IoSpecKind specKind2) const {
945   if (specifierSet_.test(specKind1) && !specifierSet_.test(specKind2)) {
946     context_.Say("If %s appears, %s must also appear"_err_en_US,
947         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
948         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
949   }
950 }
951 
952 void IoChecker::CheckForRequiredSpecifier(
953     IoSpecKind specKind, bool condition, const std::string &s) const {
954   if (specifierSet_.test(specKind) && !condition) {
955     context_.Say("If %s appears, %s must also appear"_err_en_US,
956         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
957   }
958 }
959 
960 void IoChecker::CheckForRequiredSpecifier(
961     bool condition, const std::string &s, IoSpecKind specKind) const {
962   if (condition && !specifierSet_.test(specKind)) {
963     context_.Say("If %s appears, %s must also appear"_err_en_US, s,
964         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
965   }
966 }
967 
968 void IoChecker::CheckForRequiredSpecifier(bool condition1,
969     const std::string &s1, bool condition2, const std::string &s2) const {
970   if (condition1 && !condition2) {
971     context_.Say("If %s appears, %s must also appear"_err_en_US, s1, s2);
972   }
973 }
974 
975 void IoChecker::CheckForProhibitedSpecifier(IoSpecKind specKind) const {
976   if (specifierSet_.test(specKind)) {
977     context_.Say("%s statement must not have a %s specifier"_err_en_US,
978         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
979         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
980   }
981 }
982 
983 void IoChecker::CheckForProhibitedSpecifier(
984     IoSpecKind specKind1, IoSpecKind specKind2) const {
985   if (specifierSet_.test(specKind1) && specifierSet_.test(specKind2)) {
986     context_.Say("If %s appears, %s must not appear"_err_en_US,
987         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
988         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
989   }
990 }
991 
992 void IoChecker::CheckForProhibitedSpecifier(
993     IoSpecKind specKind, bool condition, const std::string &s) const {
994   if (specifierSet_.test(specKind) && condition) {
995     context_.Say("If %s appears, %s must not appear"_err_en_US,
996         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
997   }
998 }
999 
1000 void IoChecker::CheckForProhibitedSpecifier(
1001     bool condition, const std::string &s, IoSpecKind specKind) const {
1002   if (condition && specifierSet_.test(specKind)) {
1003     context_.Say("If %s appears, %s must not appear"_err_en_US, s,
1004         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
1005   }
1006 }
1007 
1008 template <typename A>
1009 void IoChecker::CheckForDefinableVariable(
1010     const A &variable, const std::string &s) const {
1011   if (const auto *var{parser::Unwrap<parser::Variable>(variable)}) {
1012     if (auto expr{AnalyzeExpr(context_, *var)}) {
1013       auto at{var->GetSource()};
1014       if (auto whyNot{WhyNotDefinable(at, context_.FindScope(at),
1015               DefinabilityFlags{DefinabilityFlag::VectorSubscriptIsOk},
1016               *expr)}) {
1017         const Symbol *base{GetFirstSymbol(*expr)};
1018         context_
1019             .Say(at, "%s variable '%s' is not definable"_err_en_US, s,
1020                 (base ? base->name() : at).ToString())
1021             .Attach(std::move(*whyNot));
1022       }
1023     }
1024   }
1025 }
1026 
1027 void IoChecker::CheckForPureSubprogram() const { // C1597
1028   CHECK(context_.location());
1029   if (const Scope *
1030       scope{context_.globalScope().FindScope(*context_.location())}) {
1031     if (FindPureProcedureContaining(*scope)) {
1032       context_.Say(
1033           "External I/O is not allowed in a pure subprogram"_err_en_US);
1034     }
1035   }
1036 }
1037 
1038 // Seeks out an allocatable or pointer ultimate component that is not
1039 // nested in a nonallocatable/nonpointer component with a specific
1040 // defined I/O procedure.
1041 static const Symbol *FindUnsafeIoDirectComponent(GenericKind::DefinedIo which,
1042     const DerivedTypeSpec &derived, const Scope &scope) {
1043   if (HasDefinedIo(which, derived, &scope)) {
1044     return nullptr;
1045   }
1046   if (const Scope * dtScope{derived.scope()}) {
1047     for (const auto &pair : *dtScope) {
1048       const Symbol &symbol{*pair.second};
1049       if (IsAllocatableOrPointer(symbol)) {
1050         return &symbol;
1051       }
1052       if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
1053         if (const DeclTypeSpec * type{details->type()}) {
1054           if (type->category() == DeclTypeSpec::Category::TypeDerived) {
1055             const DerivedTypeSpec &componentDerived{type->derivedTypeSpec()};
1056             if (const Symbol *
1057                 bad{FindUnsafeIoDirectComponent(
1058                     which, componentDerived, scope)}) {
1059               return bad;
1060             }
1061           }
1062         }
1063       }
1064     }
1065   }
1066   return nullptr;
1067 }
1068 
1069 // For a type that does not have a defined I/O subroutine, finds a direct
1070 // component that is a witness to an accessibility violation outside the module
1071 // in which the type was defined.
1072 static const Symbol *FindInaccessibleComponent(GenericKind::DefinedIo which,
1073     const DerivedTypeSpec &derived, const Scope &scope) {
1074   if (const Scope * dtScope{derived.scope()}) {
1075     if (const Scope * module{FindModuleContaining(*dtScope)}) {
1076       for (const auto &pair : *dtScope) {
1077         const Symbol &symbol{*pair.second};
1078         if (IsAllocatableOrPointer(symbol)) {
1079           continue; // already an error
1080         }
1081         if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
1082           const DerivedTypeSpec *componentDerived{nullptr};
1083           if (const DeclTypeSpec * type{details->type()}) {
1084             if (type->category() == DeclTypeSpec::Category::TypeDerived) {
1085               componentDerived = &type->derivedTypeSpec();
1086             }
1087           }
1088           if (componentDerived &&
1089               HasDefinedIo(which, *componentDerived, &scope)) {
1090             continue; // this component and its descendents are fine
1091           }
1092           if (symbol.attrs().test(Attr::PRIVATE) &&
1093               !symbol.test(Symbol::Flag::ParentComp)) {
1094             if (!DoesScopeContain(module, scope)) {
1095               return &symbol;
1096             }
1097           }
1098           if (componentDerived) {
1099             if (const Symbol *
1100                 bad{FindInaccessibleComponent(
1101                     which, *componentDerived, scope)}) {
1102               return bad;
1103             }
1104           }
1105         }
1106       }
1107     }
1108   }
1109   return nullptr;
1110 }
1111 
1112 // Fortran 2018, 12.6.3 paragraphs 5 & 7
1113 parser::Message *IoChecker::CheckForBadIoType(const evaluate::DynamicType &type,
1114     GenericKind::DefinedIo which, parser::CharBlock where) const {
1115   if (type.IsUnlimitedPolymorphic()) {
1116     return &context_.Say(
1117         where, "I/O list item may not be unlimited polymorphic"_err_en_US);
1118   } else if (type.category() == TypeCategory::Derived) {
1119     const auto &derived{type.GetDerivedTypeSpec()};
1120     const Scope &scope{context_.FindScope(where)};
1121     if (const Symbol *
1122         bad{FindUnsafeIoDirectComponent(which, derived, scope)}) {
1123       return &context_.SayWithDecl(*bad, where,
1124           "Derived type '%s' in I/O cannot have an allocatable or pointer direct component '%s' unless using defined I/O"_err_en_US,
1125           derived.name(), bad->name());
1126     }
1127     if (!HasDefinedIo(which, derived, &scope)) {
1128       if (type.IsPolymorphic()) {
1129         return &context_.Say(where,
1130             "Derived type '%s' in I/O may not be polymorphic unless using defined I/O"_err_en_US,
1131             derived.name());
1132       }
1133       if (const Symbol *
1134           bad{FindInaccessibleComponent(which, derived, scope)}) {
1135         return &context_.Say(where,
1136             "I/O of the derived type '%s' may not be performed without defined I/O in a scope in which a direct component like '%s' is inaccessible"_err_en_US,
1137             derived.name(), bad->name());
1138       }
1139     }
1140   }
1141   return nullptr;
1142 }
1143 
1144 void IoChecker::CheckForBadIoType(const SomeExpr &expr,
1145     GenericKind::DefinedIo which, parser::CharBlock where) const {
1146   if (auto type{expr.GetType()}) {
1147     CheckForBadIoType(*type, which, where);
1148   }
1149 }
1150 
1151 parser::Message *IoChecker::CheckForBadIoType(const Symbol &symbol,
1152     GenericKind::DefinedIo which, parser::CharBlock where) const {
1153   if (auto type{evaluate::DynamicType::From(symbol)}) {
1154     if (auto *msg{CheckForBadIoType(*type, which, where)}) {
1155       evaluate::AttachDeclaration(*msg, symbol);
1156       return msg;
1157     }
1158   }
1159   return nullptr;
1160 }
1161 
1162 void IoChecker::CheckNamelist(const Symbol &namelist,
1163     GenericKind::DefinedIo which, parser::CharBlock namelistLocation) const {
1164   const auto &details{namelist.GetUltimate().get<NamelistDetails>()};
1165   for (const Symbol &object : details.objects()) {
1166     context_.CheckIndexVarRedefine(namelistLocation, object);
1167     if (auto *msg{CheckForBadIoType(object, which, namelistLocation)}) {
1168       evaluate::AttachDeclaration(*msg, namelist);
1169     }
1170   }
1171 }
1172 
1173 } // namespace Fortran::semantics
1174