xref: /llvm-project/flang/lib/Semantics/check-io.cpp (revision 191d48723f8b853a6ad65532c173c67155cbe606) 
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 &&
39       !context_.ShouldWarn(common::LanguageFeature::AdditionalFormats)) {
40     return false;
41   }
42   parser::MessageFormattedText text{
43       parser::MessageFixedText{msg.text, strlen(msg.text),
44           msg.isError ? parser::Severity::Error : parser::Severity::Warning},
45       msg.arg};
46   if (formatCharBlock_.size()) {
47     // The input format is a folded expression.  Error markers span the full
48     // original unfolded expression in formatCharBlock_.
49     context_.Say(formatCharBlock_, text);
50   } else {
51     // The input format is a source expression.  Error markers have an offset
52     // and length relative to the beginning of formatCharBlock_.
53     parser::CharBlock messageCharBlock{
54         parser::CharBlock(formatCharBlock_.begin() + msg.offset, msg.length)};
55     context_.Say(messageCharBlock, text);
56   }
57   return msg.isError && --errorAllowance_ <= 0;
58 }
59 
60 void IoChecker::Enter(
61     const parser::Statement<common::Indirection<parser::FormatStmt>> &stmt) {
62   if (!stmt.label) {
63     context_.Say("Format statement must be labeled"_err_en_US); // C1301
64   }
65   const char *formatStart{static_cast<const char *>(
66       std::memchr(stmt.source.begin(), '(', stmt.source.size()))};
67   parser::CharBlock reporterCharBlock{formatStart, static_cast<std::size_t>(0)};
68   FormatErrorReporter reporter{context_, reporterCharBlock};
69   auto reporterWrapper{[&](const auto &msg) { return reporter.Say(msg); }};
70   switch (context_.GetDefaultKind(TypeCategory::Character)) {
71   case 1: {
72     common::FormatValidator<char> validator{formatStart,
73         stmt.source.size() - (formatStart - stmt.source.begin()),
74         reporterWrapper};
75     validator.Check();
76     break;
77   }
78   case 2: { // TODO: Get this to work.
79     common::FormatValidator<char16_t> validator{
80         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
81     validator.Check();
82     break;
83   }
84   case 4: { // TODO: Get this to work.
85     common::FormatValidator<char32_t> validator{
86         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
87     validator.Check();
88     break;
89   }
90   default:
91     CRASH_NO_CASE;
92   }
93 }
94 
95 void IoChecker::Enter(const parser::ConnectSpec &spec) {
96   // ConnectSpec context FileNameExpr
97   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
98     SetSpecifier(IoSpecKind::File);
99   }
100 }
101 
102 // Ignore trailing spaces (12.5.6.2 p1) and convert to upper case
103 static std::string Normalize(const std::string &value) {
104   auto upper{parser::ToUpperCaseLetters(value)};
105   std::size_t lastNonBlank{upper.find_last_not_of(' ')};
106   upper.resize(lastNonBlank == std::string::npos ? 0 : lastNonBlank + 1);
107   return upper;
108 }
109 
110 void IoChecker::Enter(const parser::ConnectSpec::CharExpr &spec) {
111   IoSpecKind specKind{};
112   using ParseKind = parser::ConnectSpec::CharExpr::Kind;
113   switch (std::get<ParseKind>(spec.t)) {
114   case ParseKind::Access:
115     specKind = IoSpecKind::Access;
116     break;
117   case ParseKind::Action:
118     specKind = IoSpecKind::Action;
119     break;
120   case ParseKind::Asynchronous:
121     specKind = IoSpecKind::Asynchronous;
122     break;
123   case ParseKind::Blank:
124     specKind = IoSpecKind::Blank;
125     break;
126   case ParseKind::Decimal:
127     specKind = IoSpecKind::Decimal;
128     break;
129   case ParseKind::Delim:
130     specKind = IoSpecKind::Delim;
131     break;
132   case ParseKind::Encoding:
133     specKind = IoSpecKind::Encoding;
134     break;
135   case ParseKind::Form:
136     specKind = IoSpecKind::Form;
137     break;
138   case ParseKind::Pad:
139     specKind = IoSpecKind::Pad;
140     break;
141   case ParseKind::Position:
142     specKind = IoSpecKind::Position;
143     break;
144   case ParseKind::Round:
145     specKind = IoSpecKind::Round;
146     break;
147   case ParseKind::Sign:
148     specKind = IoSpecKind::Sign;
149     break;
150   case ParseKind::Carriagecontrol:
151     specKind = IoSpecKind::Carriagecontrol;
152     break;
153   case ParseKind::Convert:
154     specKind = IoSpecKind::Convert;
155     break;
156   case ParseKind::Dispose:
157     specKind = IoSpecKind::Dispose;
158     break;
159   }
160   SetSpecifier(specKind);
161   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
162           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
163     std::string s{Normalize(*charConst)};
164     if (specKind == IoSpecKind::Access) {
165       flags_.set(Flag::KnownAccess);
166       flags_.set(Flag::AccessDirect, s == "DIRECT");
167       flags_.set(Flag::AccessStream, s == "STREAM");
168     }
169     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
170     if (specKind == IoSpecKind::Carriagecontrol &&
171         (s == "FORTRAN" || s == "NONE")) {
172       context_.Say(parser::FindSourceLocation(spec),
173           "Unimplemented %s value '%s'"_err_en_US,
174           parser::ToUpperCaseLetters(common::EnumToString(specKind)),
175           *charConst);
176     }
177   }
178 }
179 
180 void IoChecker::Enter(const parser::ConnectSpec::Newunit &var) {
181   CheckForDefinableVariable(var, "NEWUNIT");
182   SetSpecifier(IoSpecKind::Newunit);
183 }
184 
185 void IoChecker::Enter(const parser::ConnectSpec::Recl &spec) {
186   SetSpecifier(IoSpecKind::Recl);
187   if (const std::optional<std::int64_t> recl{
188           GetConstExpr<std::int64_t>(spec)}) {
189     if (*recl <= 0) {
190       context_.Say(parser::FindSourceLocation(spec),
191           "RECL value (%jd) must be positive"_err_en_US,
192           *recl); // 12.5.6.15
193     }
194   }
195 }
196 
197 void IoChecker::Enter(const parser::EndLabel &) {
198   SetSpecifier(IoSpecKind::End);
199 }
200 
201 void IoChecker::Enter(const parser::EorLabel &) {
202   SetSpecifier(IoSpecKind::Eor);
203 }
204 
205 void IoChecker::Enter(const parser::ErrLabel &) {
206   SetSpecifier(IoSpecKind::Err);
207 }
208 
209 void IoChecker::Enter(const parser::FileUnitNumber &) {
210   SetSpecifier(IoSpecKind::Unit);
211   flags_.set(Flag::NumberUnit);
212 }
213 
214 void IoChecker::Enter(const parser::Format &spec) {
215   SetSpecifier(IoSpecKind::Fmt);
216   flags_.set(Flag::FmtOrNml);
217   common::visit(
218       common::visitors{
219           [&](const parser::Label &) { flags_.set(Flag::LabelFmt); },
220           [&](const parser::Star &) { flags_.set(Flag::StarFmt); },
221           [&](const parser::Expr &format) {
222             const SomeExpr *expr{GetExpr(context_, format)};
223             if (!expr) {
224               return;
225             }
226             auto type{expr->GetType()};
227             if (type && type->category() == TypeCategory::Integer &&
228                 type->kind() ==
229                     context_.defaultKinds().GetDefaultKind(type->category()) &&
230                 expr->Rank() == 0) {
231               flags_.set(Flag::AssignFmt);
232               if (!IsVariable(*expr)) {
233                 context_.Say(format.source,
234                     "Assigned format label must be a scalar variable"_err_en_US);
235               } else if (context_.ShouldWarn(common::LanguageFeature::Assign)) {
236                 context_.Say(format.source,
237                     "Assigned format labels are deprecated"_port_en_US);
238               }
239               return;
240             }
241             if (type && type->category() != TypeCategory::Character &&
242                 (type->category() != TypeCategory::Integer ||
243                     expr->Rank() > 0) &&
244                 context_.IsEnabled(
245                     common::LanguageFeature::NonCharacterFormat)) {
246               // Legacy extension: using non-character variables, typically
247               // DATA-initialized with Hollerith, as format expressions.
248               if (context_.ShouldWarn(
249                       common::LanguageFeature::NonCharacterFormat)) {
250                 context_.Say(format.source,
251                     "Non-character format expression is not standard"_port_en_US);
252               }
253             } else if (!type ||
254                 type->kind() !=
255                     context_.defaultKinds().GetDefaultKind(type->category())) {
256               context_.Say(format.source,
257                   "Format expression must be default character or default scalar integer"_err_en_US);
258               return;
259             }
260             flags_.set(Flag::CharFmt);
261             const std::optional<std::string> constantFormat{
262                 GetConstExpr<std::string>(format)};
263             if (!constantFormat) {
264               return;
265             }
266             // validate constant format -- 12.6.2.2
267             bool isFolded{constantFormat->size() != format.source.size() - 2};
268             parser::CharBlock reporterCharBlock{isFolded
269                     ? parser::CharBlock{format.source}
270                     : parser::CharBlock{format.source.begin() + 1,
271                           static_cast<std::size_t>(0)}};
272             FormatErrorReporter reporter{context_, reporterCharBlock};
273             auto reporterWrapper{
274                 [&](const auto &msg) { return reporter.Say(msg); }};
275             switch (context_.GetDefaultKind(TypeCategory::Character)) {
276             case 1: {
277               common::FormatValidator<char> validator{constantFormat->c_str(),
278                   constantFormat->length(), reporterWrapper, stmt_};
279               validator.Check();
280               break;
281             }
282             case 2: {
283               // TODO: Get this to work.  (Maybe combine with earlier instance?)
284               common::FormatValidator<char16_t> validator{
285                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
286               validator.Check();
287               break;
288             }
289             case 4: {
290               // TODO: Get this to work.  (Maybe combine with earlier instance?)
291               common::FormatValidator<char32_t> validator{
292                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
293               validator.Check();
294               break;
295             }
296             default:
297               CRASH_NO_CASE;
298             }
299           },
300       },
301       spec.u);
302 }
303 
304 void IoChecker::Enter(const parser::IdExpr &) { SetSpecifier(IoSpecKind::Id); }
305 
306 void IoChecker::Enter(const parser::IdVariable &spec) {
307   SetSpecifier(IoSpecKind::Id);
308   const auto *expr{GetExpr(context_, spec)};
309   if (!expr || !expr->GetType()) {
310     return;
311   }
312   CheckForDefinableVariable(spec, "ID");
313   int kind{expr->GetType()->kind()};
314   int defaultKind{context_.GetDefaultKind(TypeCategory::Integer)};
315   if (kind < defaultKind) {
316     context_.Say(
317         "ID kind (%d) is smaller than default INTEGER kind (%d)"_err_en_US,
318         std::move(kind), std::move(defaultKind)); // C1229
319   }
320 }
321 
322 void IoChecker::Enter(const parser::InputItem &spec) {
323   flags_.set(Flag::DataList);
324   const parser::Variable *var{std::get_if<parser::Variable>(&spec.u)};
325   if (!var) {
326     return;
327   }
328   CheckForDefinableVariable(*var, "Input");
329   if (auto expr{AnalyzeExpr(context_, *var)}) {
330     CheckForBadIoType(*expr,
331         flags_.test(Flag::FmtOrNml) ? common::DefinedIo::ReadFormatted
332                                     : common::DefinedIo::ReadUnformatted,
333         var->GetSource());
334   }
335 }
336 
337 void IoChecker::Enter(const parser::InquireSpec &spec) {
338   // InquireSpec context FileNameExpr
339   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
340     SetSpecifier(IoSpecKind::File);
341   }
342 }
343 
344 void IoChecker::Enter(const parser::InquireSpec::CharVar &spec) {
345   IoSpecKind specKind{};
346   using ParseKind = parser::InquireSpec::CharVar::Kind;
347   switch (std::get<ParseKind>(spec.t)) {
348   case ParseKind::Access:
349     specKind = IoSpecKind::Access;
350     break;
351   case ParseKind::Action:
352     specKind = IoSpecKind::Action;
353     break;
354   case ParseKind::Asynchronous:
355     specKind = IoSpecKind::Asynchronous;
356     break;
357   case ParseKind::Blank:
358     specKind = IoSpecKind::Blank;
359     break;
360   case ParseKind::Decimal:
361     specKind = IoSpecKind::Decimal;
362     break;
363   case ParseKind::Delim:
364     specKind = IoSpecKind::Delim;
365     break;
366   case ParseKind::Direct:
367     specKind = IoSpecKind::Direct;
368     break;
369   case ParseKind::Encoding:
370     specKind = IoSpecKind::Encoding;
371     break;
372   case ParseKind::Form:
373     specKind = IoSpecKind::Form;
374     break;
375   case ParseKind::Formatted:
376     specKind = IoSpecKind::Formatted;
377     break;
378   case ParseKind::Iomsg:
379     specKind = IoSpecKind::Iomsg;
380     break;
381   case ParseKind::Name:
382     specKind = IoSpecKind::Name;
383     break;
384   case ParseKind::Pad:
385     specKind = IoSpecKind::Pad;
386     break;
387   case ParseKind::Position:
388     specKind = IoSpecKind::Position;
389     break;
390   case ParseKind::Read:
391     specKind = IoSpecKind::Read;
392     break;
393   case ParseKind::Readwrite:
394     specKind = IoSpecKind::Readwrite;
395     break;
396   case ParseKind::Round:
397     specKind = IoSpecKind::Round;
398     break;
399   case ParseKind::Sequential:
400     specKind = IoSpecKind::Sequential;
401     break;
402   case ParseKind::Sign:
403     specKind = IoSpecKind::Sign;
404     break;
405   case ParseKind::Status:
406     specKind = IoSpecKind::Status;
407     break;
408   case ParseKind::Stream:
409     specKind = IoSpecKind::Stream;
410     break;
411   case ParseKind::Unformatted:
412     specKind = IoSpecKind::Unformatted;
413     break;
414   case ParseKind::Write:
415     specKind = IoSpecKind::Write;
416     break;
417   case ParseKind::Carriagecontrol:
418     specKind = IoSpecKind::Carriagecontrol;
419     break;
420   case ParseKind::Convert:
421     specKind = IoSpecKind::Convert;
422     break;
423   case ParseKind::Dispose:
424     specKind = IoSpecKind::Dispose;
425     break;
426   }
427   CheckForDefinableVariable(std::get<parser::ScalarDefaultCharVariable>(spec.t),
428       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
429   SetSpecifier(specKind);
430 }
431 
432 void IoChecker::Enter(const parser::InquireSpec::IntVar &spec) {
433   IoSpecKind specKind{};
434   using ParseKind = parser::InquireSpec::IntVar::Kind;
435   switch (std::get<parser::InquireSpec::IntVar::Kind>(spec.t)) {
436   case ParseKind::Iostat:
437     specKind = IoSpecKind::Iostat;
438     break;
439   case ParseKind::Nextrec:
440     specKind = IoSpecKind::Nextrec;
441     break;
442   case ParseKind::Number:
443     specKind = IoSpecKind::Number;
444     break;
445   case ParseKind::Pos:
446     specKind = IoSpecKind::Pos;
447     break;
448   case ParseKind::Recl:
449     specKind = IoSpecKind::Recl;
450     break;
451   case ParseKind::Size:
452     specKind = IoSpecKind::Size;
453     break;
454   }
455   CheckForDefinableVariable(std::get<parser::ScalarIntVariable>(spec.t),
456       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
457   SetSpecifier(specKind);
458 }
459 
460 void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
461   IoSpecKind specKind{};
462   using ParseKind = parser::InquireSpec::LogVar::Kind;
463   switch (std::get<parser::InquireSpec::LogVar::Kind>(spec.t)) {
464   case ParseKind::Exist:
465     specKind = IoSpecKind::Exist;
466     break;
467   case ParseKind::Named:
468     specKind = IoSpecKind::Named;
469     break;
470   case ParseKind::Opened:
471     specKind = IoSpecKind::Opened;
472     break;
473   case ParseKind::Pending:
474     specKind = IoSpecKind::Pending;
475     break;
476   }
477   SetSpecifier(specKind);
478 }
479 
480 void IoChecker::Enter(const parser::IoControlSpec &spec) {
481   // IoControlSpec context Name
482   flags_.set(Flag::IoControlList);
483   if (std::holds_alternative<parser::Name>(spec.u)) {
484     SetSpecifier(IoSpecKind::Nml);
485     flags_.set(Flag::FmtOrNml);
486   }
487 }
488 
489 void IoChecker::Enter(const parser::IoControlSpec::Asynchronous &spec) {
490   SetSpecifier(IoSpecKind::Asynchronous);
491   if (const std::optional<std::string> charConst{
492           GetConstExpr<std::string>(spec)}) {
493     flags_.set(Flag::AsynchronousYes, Normalize(*charConst) == "YES");
494     CheckStringValue(IoSpecKind::Asynchronous, *charConst,
495         parser::FindSourceLocation(spec)); // C1223
496   }
497 }
498 
499 void IoChecker::Enter(const parser::IoControlSpec::CharExpr &spec) {
500   IoSpecKind specKind{};
501   using ParseKind = parser::IoControlSpec::CharExpr::Kind;
502   switch (std::get<ParseKind>(spec.t)) {
503   case ParseKind::Advance:
504     specKind = IoSpecKind::Advance;
505     break;
506   case ParseKind::Blank:
507     specKind = IoSpecKind::Blank;
508     break;
509   case ParseKind::Decimal:
510     specKind = IoSpecKind::Decimal;
511     break;
512   case ParseKind::Delim:
513     specKind = IoSpecKind::Delim;
514     break;
515   case ParseKind::Pad:
516     specKind = IoSpecKind::Pad;
517     break;
518   case ParseKind::Round:
519     specKind = IoSpecKind::Round;
520     break;
521   case ParseKind::Sign:
522     specKind = IoSpecKind::Sign;
523     break;
524   }
525   SetSpecifier(specKind);
526   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
527           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
528     if (specKind == IoSpecKind::Advance) {
529       flags_.set(Flag::AdvanceYes, Normalize(*charConst) == "YES");
530     }
531     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
532   }
533 }
534 
535 void IoChecker::Enter(const parser::IoControlSpec::Pos &) {
536   SetSpecifier(IoSpecKind::Pos);
537 }
538 
539 void IoChecker::Enter(const parser::IoControlSpec::Rec &) {
540   SetSpecifier(IoSpecKind::Rec);
541 }
542 
543 void IoChecker::Enter(const parser::IoControlSpec::Size &var) {
544   CheckForDefinableVariable(var, "SIZE");
545   SetSpecifier(IoSpecKind::Size);
546 }
547 
548 void IoChecker::Enter(const parser::IoUnit &spec) {
549   if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
550     // Only now after generic resolution can it be known whether a function
551     // call appearing as UNIT=f() is an integer scalar external unit number
552     // or a character pointer for internal I/O.
553     const auto *expr{GetExpr(context_, *var)};
554     std::optional<evaluate::DynamicType> dyType;
555     if (expr) {
556       dyType = expr->GetType();
557     }
558     if (dyType && dyType->category() == TypeCategory::Integer) {
559       if (expr->Rank() != 0) {
560         context_.Say(parser::FindSourceLocation(*var),
561             "I/O unit number must be scalar"_err_en_US);
562       }
563       // In the case of an integer unit number variable, rewrite the parse
564       // tree as if the unit had been parsed as a FileUnitNumber in order
565       // to ease lowering.
566       auto &mutableSpec{const_cast<parser::IoUnit &>(spec)};
567       auto &mutableVar{std::get<parser::Variable>(mutableSpec.u)};
568       auto source{mutableVar.GetSource()};
569       auto typedExpr{std::move(mutableVar.typedExpr)};
570       auto newExpr{common::visit(
571           [](auto &&indirection) {
572             return parser::Expr{std::move(indirection)};
573           },
574           std::move(mutableVar.u))};
575       newExpr.source = source;
576       newExpr.typedExpr = std::move(typedExpr);
577       mutableSpec.u = parser::FileUnitNumber{
578           parser::ScalarIntExpr{parser::IntExpr{std::move(newExpr)}}};
579     } else if (!dyType || dyType->category() != TypeCategory::Character) {
580       SetSpecifier(IoSpecKind::Unit);
581       context_.Say(parser::FindSourceLocation(*var),
582           "I/O unit must be a character variable or a scalar integer expression"_err_en_US);
583     } else { // CHARACTER variable (internal I/O)
584       if (stmt_ == IoStmtKind::Write) {
585         CheckForDefinableVariable(*var, "Internal file");
586       }
587       if (HasVectorSubscript(*expr)) {
588         context_.Say(parser::FindSourceLocation(*var), // C1201
589             "Internal file must not have a vector subscript"_err_en_US);
590       }
591       SetSpecifier(IoSpecKind::Unit);
592       flags_.set(Flag::InternalUnit);
593     }
594   } else if (std::get_if<parser::Star>(&spec.u)) {
595     SetSpecifier(IoSpecKind::Unit);
596     flags_.set(Flag::StarUnit);
597   }
598 }
599 
600 void IoChecker::Enter(const parser::MsgVariable &var) {
601   if (stmt_ == IoStmtKind::None) {
602     // allocate, deallocate, image control
603     CheckForDefinableVariable(var, "ERRMSG");
604     return;
605   }
606   CheckForDefinableVariable(var, "IOMSG");
607   SetSpecifier(IoSpecKind::Iomsg);
608 }
609 
610 void IoChecker::Enter(const parser::OutputItem &item) {
611   flags_.set(Flag::DataList);
612   if (const auto *x{std::get_if<parser::Expr>(&item.u)}) {
613     if (const auto *expr{GetExpr(context_, *x)}) {
614       if (evaluate::IsBOZLiteral(*expr)) {
615         context_.Say(parser::FindSourceLocation(*x), // C7109
616             "Output item must not be a BOZ literal constant"_err_en_US);
617       } else if (IsProcedure(*expr)) {
618         context_.Say(parser::FindSourceLocation(*x),
619             "Output item must not be a procedure"_err_en_US); // C1233
620       }
621       CheckForBadIoType(*expr,
622           flags_.test(Flag::FmtOrNml) ? common::DefinedIo::WriteFormatted
623                                       : common::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, common::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, common::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_.ShouldWarn(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(common::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(common::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     common::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, common::DefinedIo which,
1144     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     common::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, common::DefinedIo which,
1162     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