xref: /llvm-project/flang/lib/Semantics/check-io.cpp (revision 5ea0ba2c13af3c6c8e68701b00695f0f0481bed0) 
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               }
235               return;
236             }
237             if (type && type->category() != TypeCategory::Character &&
238                 (type->category() != TypeCategory::Integer ||
239                     expr->Rank() > 0) &&
240                 context_.IsEnabled(
241                     common::LanguageFeature::NonCharacterFormat)) {
242               // Legacy extension: using non-character variables, typically
243               // DATA-initialized with Hollerith, as format expressions.
244               if (context_.ShouldWarn(
245                       common::LanguageFeature::NonCharacterFormat)) {
246                 context_.Say(format.source,
247                     "Non-character format expression is not standard"_port_en_US);
248               }
249             } else if (!type ||
250                 type->kind() !=
251                     context_.defaultKinds().GetDefaultKind(type->category())) {
252               context_.Say(format.source,
253                   "Format expression must be default character or default scalar integer"_err_en_US);
254               return;
255             }
256             flags_.set(Flag::CharFmt);
257             const std::optional<std::string> constantFormat{
258                 GetConstExpr<std::string>(format)};
259             if (!constantFormat) {
260               return;
261             }
262             // validate constant format -- 12.6.2.2
263             bool isFolded{constantFormat->size() != format.source.size() - 2};
264             parser::CharBlock reporterCharBlock{isFolded
265                     ? parser::CharBlock{format.source}
266                     : parser::CharBlock{format.source.begin() + 1,
267                           static_cast<std::size_t>(0)}};
268             FormatErrorReporter reporter{context_, reporterCharBlock};
269             auto reporterWrapper{
270                 [&](const auto &msg) { return reporter.Say(msg); }};
271             switch (context_.GetDefaultKind(TypeCategory::Character)) {
272             case 1: {
273               common::FormatValidator<char> validator{constantFormat->c_str(),
274                   constantFormat->length(), reporterWrapper, stmt_};
275               validator.Check();
276               break;
277             }
278             case 2: {
279               // TODO: Get this to work.  (Maybe combine with earlier instance?)
280               common::FormatValidator<char16_t> validator{
281                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
282               validator.Check();
283               break;
284             }
285             case 4: {
286               // TODO: Get this to work.  (Maybe combine with earlier instance?)
287               common::FormatValidator<char32_t> validator{
288                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
289               validator.Check();
290               break;
291             }
292             default:
293               CRASH_NO_CASE;
294             }
295           },
296       },
297       spec.u);
298 }
299 
300 void IoChecker::Enter(const parser::IdExpr &) { SetSpecifier(IoSpecKind::Id); }
301 
302 void IoChecker::Enter(const parser::IdVariable &spec) {
303   SetSpecifier(IoSpecKind::Id);
304   const auto *expr{GetExpr(context_, spec)};
305   if (!expr || !expr->GetType()) {
306     return;
307   }
308   CheckForDefinableVariable(spec, "ID");
309   int kind{expr->GetType()->kind()};
310   int defaultKind{context_.GetDefaultKind(TypeCategory::Integer)};
311   if (kind < defaultKind) {
312     context_.Say(
313         "ID kind (%d) is smaller than default INTEGER kind (%d)"_err_en_US,
314         std::move(kind), std::move(defaultKind)); // C1229
315   }
316 }
317 
318 void IoChecker::Enter(const parser::InputItem &spec) {
319   flags_.set(Flag::DataList);
320   const parser::Variable *var{std::get_if<parser::Variable>(&spec.u)};
321   if (!var) {
322     return;
323   }
324   CheckForDefinableVariable(*var, "Input");
325   if (auto expr{AnalyzeExpr(context_, *var)}) {
326     CheckForBadIoType(*expr,
327         flags_.test(Flag::FmtOrNml) ? GenericKind::DefinedIo::ReadFormatted
328                                     : GenericKind::DefinedIo::ReadUnformatted,
329         var->GetSource());
330   }
331 }
332 
333 void IoChecker::Enter(const parser::InquireSpec &spec) {
334   // InquireSpec context FileNameExpr
335   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
336     SetSpecifier(IoSpecKind::File);
337   }
338 }
339 
340 void IoChecker::Enter(const parser::InquireSpec::CharVar &spec) {
341   IoSpecKind specKind{};
342   using ParseKind = parser::InquireSpec::CharVar::Kind;
343   switch (std::get<ParseKind>(spec.t)) {
344   case ParseKind::Access:
345     specKind = IoSpecKind::Access;
346     break;
347   case ParseKind::Action:
348     specKind = IoSpecKind::Action;
349     break;
350   case ParseKind::Asynchronous:
351     specKind = IoSpecKind::Asynchronous;
352     break;
353   case ParseKind::Blank:
354     specKind = IoSpecKind::Blank;
355     break;
356   case ParseKind::Decimal:
357     specKind = IoSpecKind::Decimal;
358     break;
359   case ParseKind::Delim:
360     specKind = IoSpecKind::Delim;
361     break;
362   case ParseKind::Direct:
363     specKind = IoSpecKind::Direct;
364     break;
365   case ParseKind::Encoding:
366     specKind = IoSpecKind::Encoding;
367     break;
368   case ParseKind::Form:
369     specKind = IoSpecKind::Form;
370     break;
371   case ParseKind::Formatted:
372     specKind = IoSpecKind::Formatted;
373     break;
374   case ParseKind::Iomsg:
375     specKind = IoSpecKind::Iomsg;
376     break;
377   case ParseKind::Name:
378     specKind = IoSpecKind::Name;
379     break;
380   case ParseKind::Pad:
381     specKind = IoSpecKind::Pad;
382     break;
383   case ParseKind::Position:
384     specKind = IoSpecKind::Position;
385     break;
386   case ParseKind::Read:
387     specKind = IoSpecKind::Read;
388     break;
389   case ParseKind::Readwrite:
390     specKind = IoSpecKind::Readwrite;
391     break;
392   case ParseKind::Round:
393     specKind = IoSpecKind::Round;
394     break;
395   case ParseKind::Sequential:
396     specKind = IoSpecKind::Sequential;
397     break;
398   case ParseKind::Sign:
399     specKind = IoSpecKind::Sign;
400     break;
401   case ParseKind::Status:
402     specKind = IoSpecKind::Status;
403     break;
404   case ParseKind::Stream:
405     specKind = IoSpecKind::Stream;
406     break;
407   case ParseKind::Unformatted:
408     specKind = IoSpecKind::Unformatted;
409     break;
410   case ParseKind::Write:
411     specKind = IoSpecKind::Write;
412     break;
413   case ParseKind::Carriagecontrol:
414     specKind = IoSpecKind::Carriagecontrol;
415     break;
416   case ParseKind::Convert:
417     specKind = IoSpecKind::Convert;
418     break;
419   case ParseKind::Dispose:
420     specKind = IoSpecKind::Dispose;
421     break;
422   }
423   CheckForDefinableVariable(std::get<parser::ScalarDefaultCharVariable>(spec.t),
424       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
425   SetSpecifier(specKind);
426 }
427 
428 void IoChecker::Enter(const parser::InquireSpec::IntVar &spec) {
429   IoSpecKind specKind{};
430   using ParseKind = parser::InquireSpec::IntVar::Kind;
431   switch (std::get<parser::InquireSpec::IntVar::Kind>(spec.t)) {
432   case ParseKind::Iostat:
433     specKind = IoSpecKind::Iostat;
434     break;
435   case ParseKind::Nextrec:
436     specKind = IoSpecKind::Nextrec;
437     break;
438   case ParseKind::Number:
439     specKind = IoSpecKind::Number;
440     break;
441   case ParseKind::Pos:
442     specKind = IoSpecKind::Pos;
443     break;
444   case ParseKind::Recl:
445     specKind = IoSpecKind::Recl;
446     break;
447   case ParseKind::Size:
448     specKind = IoSpecKind::Size;
449     break;
450   }
451   CheckForDefinableVariable(std::get<parser::ScalarIntVariable>(spec.t),
452       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
453   SetSpecifier(specKind);
454 }
455 
456 void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
457   IoSpecKind specKind{};
458   using ParseKind = parser::InquireSpec::LogVar::Kind;
459   switch (std::get<parser::InquireSpec::LogVar::Kind>(spec.t)) {
460   case ParseKind::Exist:
461     specKind = IoSpecKind::Exist;
462     break;
463   case ParseKind::Named:
464     specKind = IoSpecKind::Named;
465     break;
466   case ParseKind::Opened:
467     specKind = IoSpecKind::Opened;
468     break;
469   case ParseKind::Pending:
470     specKind = IoSpecKind::Pending;
471     break;
472   }
473   SetSpecifier(specKind);
474 }
475 
476 void IoChecker::Enter(const parser::IoControlSpec &spec) {
477   // IoControlSpec context Name
478   flags_.set(Flag::IoControlList);
479   if (std::holds_alternative<parser::Name>(spec.u)) {
480     SetSpecifier(IoSpecKind::Nml);
481     flags_.set(Flag::FmtOrNml);
482   }
483 }
484 
485 void IoChecker::Enter(const parser::IoControlSpec::Asynchronous &spec) {
486   SetSpecifier(IoSpecKind::Asynchronous);
487   if (const std::optional<std::string> charConst{
488           GetConstExpr<std::string>(spec)}) {
489     flags_.set(Flag::AsynchronousYes, Normalize(*charConst) == "YES");
490     CheckStringValue(IoSpecKind::Asynchronous, *charConst,
491         parser::FindSourceLocation(spec)); // C1223
492   }
493 }
494 
495 void IoChecker::Enter(const parser::IoControlSpec::CharExpr &spec) {
496   IoSpecKind specKind{};
497   using ParseKind = parser::IoControlSpec::CharExpr::Kind;
498   switch (std::get<ParseKind>(spec.t)) {
499   case ParseKind::Advance:
500     specKind = IoSpecKind::Advance;
501     break;
502   case ParseKind::Blank:
503     specKind = IoSpecKind::Blank;
504     break;
505   case ParseKind::Decimal:
506     specKind = IoSpecKind::Decimal;
507     break;
508   case ParseKind::Delim:
509     specKind = IoSpecKind::Delim;
510     break;
511   case ParseKind::Pad:
512     specKind = IoSpecKind::Pad;
513     break;
514   case ParseKind::Round:
515     specKind = IoSpecKind::Round;
516     break;
517   case ParseKind::Sign:
518     specKind = IoSpecKind::Sign;
519     break;
520   }
521   SetSpecifier(specKind);
522   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
523           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
524     if (specKind == IoSpecKind::Advance) {
525       flags_.set(Flag::AdvanceYes, Normalize(*charConst) == "YES");
526     }
527     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
528   }
529 }
530 
531 void IoChecker::Enter(const parser::IoControlSpec::Pos &) {
532   SetSpecifier(IoSpecKind::Pos);
533 }
534 
535 void IoChecker::Enter(const parser::IoControlSpec::Rec &) {
536   SetSpecifier(IoSpecKind::Rec);
537 }
538 
539 void IoChecker::Enter(const parser::IoControlSpec::Size &var) {
540   CheckForDefinableVariable(var, "SIZE");
541   SetSpecifier(IoSpecKind::Size);
542 }
543 
544 void IoChecker::Enter(const parser::IoUnit &spec) {
545   if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
546     // Only now after generic resolution can it be known whether a function
547     // call appearing as UNIT=f() is an integer scalar external unit number
548     // or a character pointer for internal I/O.
549     const auto *expr{GetExpr(context_, *var)};
550     std::optional<evaluate::DynamicType> dyType;
551     if (expr) {
552       dyType = expr->GetType();
553     }
554     if (dyType && dyType->category() == TypeCategory::Integer) {
555       if (expr->Rank() != 0) {
556         context_.Say(parser::FindSourceLocation(*var),
557             "I/O unit number must be scalar"_err_en_US);
558       }
559       // In the case of an integer unit number variable, rewrite the parse
560       // tree as if the unit had been parsed as a FileUnitNumber in order
561       // to ease lowering.
562       auto &mutableSpec{const_cast<parser::IoUnit &>(spec)};
563       auto &mutableVar{std::get<parser::Variable>(mutableSpec.u)};
564       auto source{mutableVar.GetSource()};
565       auto typedExpr{std::move(mutableVar.typedExpr)};
566       auto newExpr{common::visit(
567           [](auto &&indirection) {
568             return parser::Expr{std::move(indirection)};
569           },
570           std::move(mutableVar.u))};
571       newExpr.source = source;
572       newExpr.typedExpr = std::move(typedExpr);
573       mutableSpec.u = parser::FileUnitNumber{
574           parser::ScalarIntExpr{parser::IntExpr{std::move(newExpr)}}};
575     } else if (!dyType || dyType->category() != TypeCategory::Character) {
576       SetSpecifier(IoSpecKind::Unit);
577       context_.Say(parser::FindSourceLocation(*var),
578           "I/O unit must be a character variable or a scalar integer expression"_err_en_US);
579     } else { // CHARACTER variable (internal I/O)
580       if (stmt_ == IoStmtKind::Write) {
581         CheckForDefinableVariable(*var, "Internal file");
582       }
583       if (HasVectorSubscript(*expr)) {
584         context_.Say(parser::FindSourceLocation(*var), // C1201
585             "Internal file must not have a vector subscript"_err_en_US);
586       }
587       SetSpecifier(IoSpecKind::Unit);
588       flags_.set(Flag::InternalUnit);
589     }
590   } else if (std::get_if<parser::Star>(&spec.u)) {
591     SetSpecifier(IoSpecKind::Unit);
592     flags_.set(Flag::StarUnit);
593   }
594 }
595 
596 void IoChecker::Enter(const parser::MsgVariable &var) {
597   if (stmt_ == IoStmtKind::None) {
598     // allocate, deallocate, image control
599     CheckForDefinableVariable(var, "ERRMSG");
600     return;
601   }
602   CheckForDefinableVariable(var, "IOMSG");
603   SetSpecifier(IoSpecKind::Iomsg);
604 }
605 
606 void IoChecker::Enter(const parser::OutputItem &item) {
607   flags_.set(Flag::DataList);
608   if (const auto *x{std::get_if<parser::Expr>(&item.u)}) {
609     if (const auto *expr{GetExpr(context_, *x)}) {
610       if (evaluate::IsBOZLiteral(*expr)) {
611         context_.Say(parser::FindSourceLocation(*x), // C7109
612             "Output item must not be a BOZ literal constant"_err_en_US);
613       }
614       const Symbol *last{GetLastSymbol(*expr)};
615       if (last && IsProcedurePointer(*last)) {
616         context_.Say(parser::FindSourceLocation(*x),
617             "Output item must not be a procedure pointer"_err_en_US); // C1233
618       }
619       CheckForBadIoType(*expr,
620           flags_.test(Flag::FmtOrNml)
621               ? GenericKind::DefinedIo::WriteFormatted
622               : GenericKind::DefinedIo::WriteUnformatted,
623           parser::FindSourceLocation(item));
624     }
625   }
626 }
627 
628 void IoChecker::Enter(const parser::StatusExpr &spec) {
629   SetSpecifier(IoSpecKind::Status);
630   if (const std::optional<std::string> charConst{
631           GetConstExpr<std::string>(spec)}) {
632     // Status values for Open and Close are different.
633     std::string s{Normalize(*charConst)};
634     if (stmt_ == IoStmtKind::Open) {
635       flags_.set(Flag::KnownStatus);
636       flags_.set(Flag::StatusNew, s == "NEW");
637       flags_.set(Flag::StatusReplace, s == "REPLACE");
638       flags_.set(Flag::StatusScratch, s == "SCRATCH");
639       // CheckStringValue compares for OPEN Status string values.
640       CheckStringValue(
641           IoSpecKind::Status, *charConst, parser::FindSourceLocation(spec));
642       return;
643     }
644     CHECK(stmt_ == IoStmtKind::Close);
645     if (s != "DELETE" && s != "KEEP") {
646       context_.Say(parser::FindSourceLocation(spec),
647           "Invalid STATUS value '%s'"_err_en_US, *charConst);
648     }
649   }
650 }
651 
652 void IoChecker::Enter(const parser::StatVariable &var) {
653   if (stmt_ == IoStmtKind::None) {
654     // allocate, deallocate, image control
655     CheckForDefinableVariable(var, "STAT");
656     return;
657   }
658   CheckForDefinableVariable(var, "IOSTAT");
659   SetSpecifier(IoSpecKind::Iostat);
660 }
661 
662 void IoChecker::Leave(const parser::BackspaceStmt &) {
663   CheckForPureSubprogram();
664   CheckForRequiredSpecifier(
665       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
666   Done();
667 }
668 
669 void IoChecker::Leave(const parser::CloseStmt &) {
670   CheckForPureSubprogram();
671   CheckForRequiredSpecifier(
672       flags_.test(Flag::NumberUnit), "UNIT number"); // C1208
673   Done();
674 }
675 
676 void IoChecker::Leave(const parser::EndfileStmt &) {
677   CheckForPureSubprogram();
678   CheckForRequiredSpecifier(
679       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
680   Done();
681 }
682 
683 void IoChecker::Leave(const parser::FlushStmt &) {
684   CheckForPureSubprogram();
685   CheckForRequiredSpecifier(
686       flags_.test(Flag::NumberUnit), "UNIT number"); // C1243
687   Done();
688 }
689 
690 void IoChecker::Leave(const parser::InquireStmt &stmt) {
691   if (std::get_if<std::list<parser::InquireSpec>>(&stmt.u)) {
692     CheckForPureSubprogram();
693     // Inquire by unit or by file (vs. by output list).
694     CheckForRequiredSpecifier(
695         flags_.test(Flag::NumberUnit) || specifierSet_.test(IoSpecKind::File),
696         "UNIT number or FILE"); // C1246
697     CheckForProhibitedSpecifier(IoSpecKind::File, IoSpecKind::Unit); // C1246
698     CheckForRequiredSpecifier(IoSpecKind::Id, IoSpecKind::Pending); // C1248
699   }
700   Done();
701 }
702 
703 void IoChecker::Leave(const parser::OpenStmt &) {
704   CheckForPureSubprogram();
705   CheckForRequiredSpecifier(specifierSet_.test(IoSpecKind::Unit) ||
706           specifierSet_.test(IoSpecKind::Newunit),
707       "UNIT or NEWUNIT"); // C1204, C1205
708   CheckForProhibitedSpecifier(
709       IoSpecKind::Newunit, IoSpecKind::Unit); // C1204, C1205
710   CheckForRequiredSpecifier(flags_.test(Flag::StatusNew), "STATUS='NEW'",
711       IoSpecKind::File); // 12.5.6.10
712   CheckForRequiredSpecifier(flags_.test(Flag::StatusReplace),
713       "STATUS='REPLACE'", IoSpecKind::File); // 12.5.6.10
714   CheckForProhibitedSpecifier(flags_.test(Flag::StatusScratch),
715       "STATUS='SCRATCH'", IoSpecKind::File); // 12.5.6.10
716   if (flags_.test(Flag::KnownStatus)) {
717     CheckForRequiredSpecifier(IoSpecKind::Newunit,
718         specifierSet_.test(IoSpecKind::File) ||
719             flags_.test(Flag::StatusScratch),
720         "FILE or STATUS='SCRATCH'"); // 12.5.6.12
721   } else {
722     CheckForRequiredSpecifier(IoSpecKind::Newunit,
723         specifierSet_.test(IoSpecKind::File) ||
724             specifierSet_.test(IoSpecKind::Status),
725         "FILE or STATUS"); // 12.5.6.12
726   }
727   if (flags_.test(Flag::KnownAccess)) {
728     CheckForRequiredSpecifier(flags_.test(Flag::AccessDirect),
729         "ACCESS='DIRECT'", IoSpecKind::Recl); // 12.5.6.15
730     CheckForProhibitedSpecifier(flags_.test(Flag::AccessStream),
731         "STATUS='STREAM'", IoSpecKind::Recl); // 12.5.6.15
732   }
733   Done();
734 }
735 
736 void IoChecker::Leave(const parser::PrintStmt &) {
737   CheckForPureSubprogram();
738   Done();
739 }
740 
741 static const parser::Name *FindNamelist(
742     const std::list<parser::IoControlSpec> &controls) {
743   for (const auto &control : controls) {
744     if (const parser::Name * namelist{std::get_if<parser::Name>(&control.u)}) {
745       if (namelist->symbol &&
746           namelist->symbol->GetUltimate().has<NamelistDetails>()) {
747         return namelist;
748       }
749     }
750   }
751   return nullptr;
752 }
753 
754 static void CheckForDoVariable(
755     const parser::ReadStmt &readStmt, SemanticsContext &context) {
756   const std::list<parser::InputItem> &items{readStmt.items};
757   for (const auto &item : items) {
758     if (const parser::Variable *
759         variable{std::get_if<parser::Variable>(&item.u)}) {
760       context.CheckIndexVarRedefine(*variable);
761     }
762   }
763 }
764 
765 void IoChecker::Leave(const parser::ReadStmt &readStmt) {
766   if (!flags_.test(Flag::InternalUnit)) {
767     CheckForPureSubprogram();
768   }
769   if (const parser::Name * namelist{FindNamelist(readStmt.controls)}) {
770     if (namelist->symbol) {
771       CheckNamelist(*namelist->symbol, GenericKind::DefinedIo::ReadFormatted,
772           namelist->source);
773     }
774   }
775   CheckForDoVariable(readStmt, context_);
776   if (!flags_.test(Flag::IoControlList)) {
777     Done();
778     return;
779   }
780   LeaveReadWrite();
781   CheckForProhibitedSpecifier(IoSpecKind::Delim); // C1212
782   CheckForProhibitedSpecifier(IoSpecKind::Sign); // C1212
783   CheckForProhibitedSpecifier(IoSpecKind::Rec, IoSpecKind::End); // C1220
784   CheckForRequiredSpecifier(IoSpecKind::Eor,
785       specifierSet_.test(IoSpecKind::Advance) && !flags_.test(Flag::AdvanceYes),
786       "ADVANCE with value 'NO'"); // C1222 + 12.6.2.1p2
787   CheckForRequiredSpecifier(IoSpecKind::Blank, flags_.test(Flag::FmtOrNml),
788       "FMT or NML"); // C1227
789   CheckForRequiredSpecifier(
790       IoSpecKind::Pad, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
791   Done();
792 }
793 
794 void IoChecker::Leave(const parser::RewindStmt &) {
795   CheckForRequiredSpecifier(
796       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
797   CheckForPureSubprogram();
798   Done();
799 }
800 
801 void IoChecker::Leave(const parser::WaitStmt &) {
802   CheckForRequiredSpecifier(
803       flags_.test(Flag::NumberUnit), "UNIT number"); // C1237
804   CheckForPureSubprogram();
805   Done();
806 }
807 
808 void IoChecker::Leave(const parser::WriteStmt &writeStmt) {
809   if (!flags_.test(Flag::InternalUnit)) {
810     CheckForPureSubprogram();
811   }
812   if (const parser::Name * namelist{FindNamelist(writeStmt.controls)}) {
813     if (namelist->symbol) {
814       CheckNamelist(*namelist->symbol, GenericKind::DefinedIo::WriteFormatted,
815           namelist->source);
816     }
817   }
818   LeaveReadWrite();
819   CheckForProhibitedSpecifier(IoSpecKind::Blank); // C1213
820   CheckForProhibitedSpecifier(IoSpecKind::End); // C1213
821   CheckForProhibitedSpecifier(IoSpecKind::Eor); // C1213
822   CheckForProhibitedSpecifier(IoSpecKind::Pad); // C1213
823   CheckForProhibitedSpecifier(IoSpecKind::Size); // C1213
824   CheckForRequiredSpecifier(
825       IoSpecKind::Sign, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
826   CheckForRequiredSpecifier(IoSpecKind::Delim,
827       flags_.test(Flag::StarFmt) || specifierSet_.test(IoSpecKind::Nml),
828       "FMT=* or NML"); // C1228
829   Done();
830 }
831 
832 void IoChecker::LeaveReadWrite() const {
833   CheckForRequiredSpecifier(IoSpecKind::Unit); // C1211
834   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Rec); // C1216
835   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Fmt); // C1216
836   CheckForProhibitedSpecifier(
837       IoSpecKind::Nml, flags_.test(Flag::DataList), "a data list"); // C1216
838   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
839       "UNIT=internal-file", IoSpecKind::Pos); // C1219
840   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
841       "UNIT=internal-file", IoSpecKind::Rec); // C1219
842   CheckForProhibitedSpecifier(
843       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Pos); // C1219
844   CheckForProhibitedSpecifier(
845       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Rec); // C1219
846   CheckForProhibitedSpecifier(
847       IoSpecKind::Rec, flags_.test(Flag::StarFmt), "FMT=*"); // C1220
848   CheckForRequiredSpecifier(IoSpecKind::Advance,
849       flags_.test(Flag::CharFmt) || flags_.test(Flag::LabelFmt) ||
850           flags_.test(Flag::AssignFmt),
851       "an explicit format"); // C1221
852   CheckForProhibitedSpecifier(IoSpecKind::Advance,
853       flags_.test(Flag::InternalUnit), "UNIT=internal-file"); // C1221
854   CheckForRequiredSpecifier(flags_.test(Flag::AsynchronousYes),
855       "ASYNCHRONOUS='YES'", flags_.test(Flag::NumberUnit),
856       "UNIT=number"); // C1224
857   CheckForRequiredSpecifier(IoSpecKind::Id, flags_.test(Flag::AsynchronousYes),
858       "ASYNCHRONOUS='YES'"); // C1225
859   CheckForProhibitedSpecifier(IoSpecKind::Pos, IoSpecKind::Rec); // C1226
860   CheckForRequiredSpecifier(IoSpecKind::Decimal, flags_.test(Flag::FmtOrNml),
861       "FMT or NML"); // C1227
862   CheckForRequiredSpecifier(IoSpecKind::Round, flags_.test(Flag::FmtOrNml),
863       "FMT or NML"); // C1227
864 }
865 
866 void IoChecker::SetSpecifier(IoSpecKind specKind) {
867   if (stmt_ == IoStmtKind::None) {
868     // FMT may appear on PRINT statements, which don't have any checks.
869     // [IO]MSG and [IO]STAT parse symbols are shared with non-I/O statements.
870     return;
871   }
872   // C1203, C1207, C1210, C1236, C1239, C1242, C1245
873   if (specifierSet_.test(specKind)) {
874     context_.Say("Duplicate %s specifier"_err_en_US,
875         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
876   }
877   specifierSet_.set(specKind);
878 }
879 
880 void IoChecker::CheckStringValue(IoSpecKind specKind, const std::string &value,
881     const parser::CharBlock &source) const {
882   static std::unordered_map<IoSpecKind, const std::set<std::string>> specValues{
883       {IoSpecKind::Access, {"DIRECT", "SEQUENTIAL", "STREAM"}},
884       {IoSpecKind::Action, {"READ", "READWRITE", "WRITE"}},
885       {IoSpecKind::Advance, {"NO", "YES"}},
886       {IoSpecKind::Asynchronous, {"NO", "YES"}},
887       {IoSpecKind::Blank, {"NULL", "ZERO"}},
888       {IoSpecKind::Decimal, {"COMMA", "POINT"}},
889       {IoSpecKind::Delim, {"APOSTROPHE", "NONE", "QUOTE"}},
890       {IoSpecKind::Encoding, {"DEFAULT", "UTF-8"}},
891       {IoSpecKind::Form, {"FORMATTED", "UNFORMATTED"}},
892       {IoSpecKind::Pad, {"NO", "YES"}},
893       {IoSpecKind::Position, {"APPEND", "ASIS", "REWIND"}},
894       {IoSpecKind::Round,
895           {"COMPATIBLE", "DOWN", "NEAREST", "PROCESSOR_DEFINED", "UP", "ZERO"}},
896       {IoSpecKind::Sign, {"PLUS", "PROCESSOR_DEFINED", "SUPPRESS"}},
897       {IoSpecKind::Status,
898           // Open values; Close values are {"DELETE", "KEEP"}.
899           {"NEW", "OLD", "REPLACE", "SCRATCH", "UNKNOWN"}},
900       {IoSpecKind::Carriagecontrol, {"LIST", "FORTRAN", "NONE"}},
901       {IoSpecKind::Convert, {"BIG_ENDIAN", "LITTLE_ENDIAN", "NATIVE"}},
902       {IoSpecKind::Dispose, {"DELETE", "KEEP"}},
903   };
904   auto upper{Normalize(value)};
905   if (specValues.at(specKind).count(upper) == 0) {
906     if (specKind == IoSpecKind::Access && upper == "APPEND") {
907       if (context_.languageFeatures().ShouldWarn(
908               common::LanguageFeature::OpenAccessAppend)) {
909         context_.Say(source,
910             "ACCESS='%s' interpreted as POSITION='%s'"_port_en_US, value,
911             upper);
912       }
913     } else {
914       context_.Say(source, "Invalid %s value '%s'"_err_en_US,
915           parser::ToUpperCaseLetters(common::EnumToString(specKind)), value);
916     }
917   }
918 }
919 
920 // CheckForRequiredSpecifier and CheckForProhibitedSpecifier functions
921 // need conditions to check, and string arguments to insert into a message.
922 // An IoSpecKind provides both an absence/presence condition and a string
923 // argument (its name).  A (condition, string) pair provides an arbitrary
924 // condition and an arbitrary string.
925 
926 void IoChecker::CheckForRequiredSpecifier(IoSpecKind specKind) const {
927   if (!specifierSet_.test(specKind)) {
928     context_.Say("%s statement must have a %s specifier"_err_en_US,
929         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
930         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
931   }
932 }
933 
934 void IoChecker::CheckForRequiredSpecifier(
935     bool condition, const std::string &s) const {
936   if (!condition) {
937     context_.Say("%s statement must have a %s specifier"_err_en_US,
938         parser::ToUpperCaseLetters(common::EnumToString(stmt_)), s);
939   }
940 }
941 
942 void IoChecker::CheckForRequiredSpecifier(
943     IoSpecKind specKind1, IoSpecKind specKind2) const {
944   if (specifierSet_.test(specKind1) && !specifierSet_.test(specKind2)) {
945     context_.Say("If %s appears, %s must also appear"_err_en_US,
946         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
947         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
948   }
949 }
950 
951 void IoChecker::CheckForRequiredSpecifier(
952     IoSpecKind specKind, bool condition, const std::string &s) const {
953   if (specifierSet_.test(specKind) && !condition) {
954     context_.Say("If %s appears, %s must also appear"_err_en_US,
955         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
956   }
957 }
958 
959 void IoChecker::CheckForRequiredSpecifier(
960     bool condition, const std::string &s, IoSpecKind specKind) const {
961   if (condition && !specifierSet_.test(specKind)) {
962     context_.Say("If %s appears, %s must also appear"_err_en_US, s,
963         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
964   }
965 }
966 
967 void IoChecker::CheckForRequiredSpecifier(bool condition1,
968     const std::string &s1, bool condition2, const std::string &s2) const {
969   if (condition1 && !condition2) {
970     context_.Say("If %s appears, %s must also appear"_err_en_US, s1, s2);
971   }
972 }
973 
974 void IoChecker::CheckForProhibitedSpecifier(IoSpecKind specKind) const {
975   if (specifierSet_.test(specKind)) {
976     context_.Say("%s statement must not have a %s specifier"_err_en_US,
977         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
978         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
979   }
980 }
981 
982 void IoChecker::CheckForProhibitedSpecifier(
983     IoSpecKind specKind1, IoSpecKind specKind2) const {
984   if (specifierSet_.test(specKind1) && specifierSet_.test(specKind2)) {
985     context_.Say("If %s appears, %s must not appear"_err_en_US,
986         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
987         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
988   }
989 }
990 
991 void IoChecker::CheckForProhibitedSpecifier(
992     IoSpecKind specKind, bool condition, const std::string &s) const {
993   if (specifierSet_.test(specKind) && condition) {
994     context_.Say("If %s appears, %s must not appear"_err_en_US,
995         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
996   }
997 }
998 
999 void IoChecker::CheckForProhibitedSpecifier(
1000     bool condition, const std::string &s, IoSpecKind specKind) const {
1001   if (condition && specifierSet_.test(specKind)) {
1002     context_.Say("If %s appears, %s must not appear"_err_en_US, s,
1003         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
1004   }
1005 }
1006 
1007 template <typename A>
1008 void IoChecker::CheckForDefinableVariable(
1009     const A &variable, const std::string &s) const {
1010   if (const auto *var{parser::Unwrap<parser::Variable>(variable)}) {
1011     if (auto expr{AnalyzeExpr(context_, *var)}) {
1012       auto at{var->GetSource()};
1013       if (auto whyNot{WhyNotDefinable(at, context_.FindScope(at),
1014               DefinabilityFlags{DefinabilityFlag::VectorSubscriptIsOk},
1015               *expr)}) {
1016         const Symbol *base{GetFirstSymbol(*expr)};
1017         context_
1018             .Say(at, "%s variable '%s' is not definable"_err_en_US, s,
1019                 (base ? base->name() : at).ToString())
1020             .Attach(std::move(*whyNot));
1021       }
1022     }
1023   }
1024 }
1025 
1026 void IoChecker::CheckForPureSubprogram() const { // C1597
1027   CHECK(context_.location());
1028   if (const Scope *
1029       scope{context_.globalScope().FindScope(*context_.location())}) {
1030     if (FindPureProcedureContaining(*scope)) {
1031       context_.Say(
1032           "External I/O is not allowed in a pure subprogram"_err_en_US);
1033     }
1034   }
1035 }
1036 
1037 // Seeks out an allocatable or pointer ultimate component that is not
1038 // nested in a nonallocatable/nonpointer component with a specific
1039 // defined I/O procedure.
1040 static const Symbol *FindUnsafeIoDirectComponent(GenericKind::DefinedIo which,
1041     const DerivedTypeSpec &derived, const Scope &scope) {
1042   if (HasDefinedIo(which, derived, &scope)) {
1043     return nullptr;
1044   }
1045   if (const Scope * dtScope{derived.scope()}) {
1046     for (const auto &pair : *dtScope) {
1047       const Symbol &symbol{*pair.second};
1048       if (IsAllocatableOrPointer(symbol)) {
1049         return &symbol;
1050       }
1051       if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
1052         if (const DeclTypeSpec * type{details->type()}) {
1053           if (type->category() == DeclTypeSpec::Category::TypeDerived) {
1054             const DerivedTypeSpec &componentDerived{type->derivedTypeSpec()};
1055             if (const Symbol *
1056                 bad{FindUnsafeIoDirectComponent(
1057                     which, componentDerived, scope)}) {
1058               return bad;
1059             }
1060           }
1061         }
1062       }
1063     }
1064   }
1065   return nullptr;
1066 }
1067 
1068 // For a type that does not have a defined I/O subroutine, finds a direct
1069 // component that is a witness to an accessibility violation outside the module
1070 // in which the type was defined.
1071 static const Symbol *FindInaccessibleComponent(GenericKind::DefinedIo which,
1072     const DerivedTypeSpec &derived, const Scope &scope) {
1073   if (const Scope * dtScope{derived.scope()}) {
1074     if (const Scope * module{FindModuleContaining(*dtScope)}) {
1075       for (const auto &pair : *dtScope) {
1076         const Symbol &symbol{*pair.second};
1077         if (IsAllocatableOrPointer(symbol)) {
1078           continue; // already an error
1079         }
1080         if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
1081           const DerivedTypeSpec *componentDerived{nullptr};
1082           if (const DeclTypeSpec * type{details->type()}) {
1083             if (type->category() == DeclTypeSpec::Category::TypeDerived) {
1084               componentDerived = &type->derivedTypeSpec();
1085             }
1086           }
1087           if (componentDerived &&
1088               HasDefinedIo(which, *componentDerived, &scope)) {
1089             continue; // this component and its descendents are fine
1090           }
1091           if (symbol.attrs().test(Attr::PRIVATE) &&
1092               !symbol.test(Symbol::Flag::ParentComp)) {
1093             if (!DoesScopeContain(module, scope)) {
1094               return &symbol;
1095             }
1096           }
1097           if (componentDerived) {
1098             if (const Symbol *
1099                 bad{FindInaccessibleComponent(
1100                     which, *componentDerived, scope)}) {
1101               return bad;
1102             }
1103           }
1104         }
1105       }
1106     }
1107   }
1108   return nullptr;
1109 }
1110 
1111 // Fortran 2018, 12.6.3 paragraphs 5 & 7
1112 parser::Message *IoChecker::CheckForBadIoType(const evaluate::DynamicType &type,
1113     GenericKind::DefinedIo which, parser::CharBlock where) const {
1114   if (type.IsUnlimitedPolymorphic()) {
1115     return &context_.Say(
1116         where, "I/O list item may not be unlimited polymorphic"_err_en_US);
1117   } else if (type.category() == TypeCategory::Derived) {
1118     const auto &derived{type.GetDerivedTypeSpec()};
1119     const Scope &scope{context_.FindScope(where)};
1120     if (const Symbol *
1121         bad{FindUnsafeIoDirectComponent(which, derived, scope)}) {
1122       return &context_.SayWithDecl(*bad, where,
1123           "Derived type '%s' in I/O cannot have an allocatable or pointer direct component '%s' unless using defined I/O"_err_en_US,
1124           derived.name(), bad->name());
1125     }
1126     if (!HasDefinedIo(which, derived, &scope)) {
1127       if (type.IsPolymorphic()) {
1128         return &context_.Say(where,
1129             "Derived type '%s' in I/O may not be polymorphic unless using defined I/O"_err_en_US,
1130             derived.name());
1131       }
1132       if (const Symbol *
1133           bad{FindInaccessibleComponent(which, derived, scope)}) {
1134         return &context_.Say(where,
1135             "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,
1136             derived.name(), bad->name());
1137       }
1138     }
1139   }
1140   return nullptr;
1141 }
1142 
1143 void IoChecker::CheckForBadIoType(const SomeExpr &expr,
1144     GenericKind::DefinedIo which, parser::CharBlock where) const {
1145   if (auto type{expr.GetType()}) {
1146     CheckForBadIoType(*type, which, where);
1147   }
1148 }
1149 
1150 parser::Message *IoChecker::CheckForBadIoType(const Symbol &symbol,
1151     GenericKind::DefinedIo which, parser::CharBlock where) const {
1152   if (auto type{evaluate::DynamicType::From(symbol)}) {
1153     if (auto *msg{CheckForBadIoType(*type, which, where)}) {
1154       evaluate::AttachDeclaration(*msg, symbol);
1155       return msg;
1156     }
1157   }
1158   return nullptr;
1159 }
1160 
1161 void IoChecker::CheckNamelist(const Symbol &namelist,
1162     GenericKind::DefinedIo which, parser::CharBlock namelistLocation) const {
1163   const auto &details{namelist.GetUltimate().get<NamelistDetails>()};
1164   for (const Symbol &object : details.objects()) {
1165     context_.CheckIndexVarRedefine(namelistLocation, object);
1166     if (auto *msg{CheckForBadIoType(object, which, namelistLocation)}) {
1167       evaluate::AttachDeclaration(*msg, namelist);
1168     }
1169   }
1170 }
1171 
1172 } // namespace Fortran::semantics
1173