[flang][runtime][NFC] Clean up Fortran::common::optional<> usage (#155728)

When somebody replaced uses of std::optional<> in the runtime with a new
optional<> defined locally, many needless top-level Fortran:: namespace
qualifiers were added, which are inconsistent with namespace usage in
the runtime. Clean them up.

Author: klausler

flang-rt/include/flang-rt/runtime/connection.h

@@ -26,10 +26,10 @@ enum class Access { Sequential, Direct, Stream };
 // established in an OPEN statement.
 struct ConnectionAttributes {
   Access access{Access::Sequential}; // ACCESS='SEQUENTIAL', 'DIRECT', 'STREAM'
-  Fortran::common::optional<bool> isUnformatted; // FORM='UNFORMATTED' if true
+  common::optional<bool> isUnformatted; // FORM='UNFORMATTED' if true
   bool isUTF8{false}; // ENCODING='UTF-8'
   unsigned char internalIoCharKind{0}; // 0->external, 1/2/4->internal
-  Fortran::common::optional<std::int64_t> openRecl; // RECL= on OPEN
+  common::optional<std::int64_t> openRecl; // RECL= on OPEN
 
   RT_API_ATTRS bool IsRecordFile() const {
     // Formatted stream files are viewed as having records, at least on input
@@ -82,15 +82,14 @@ struct ConnectionState : public ConnectionAttributes {
     unterminatedRecord = false;
   }
 
-  RT_API_ATTRS Fortran::common::optional<std::int64_t>
-  EffectiveRecordLength() const {
+  RT_API_ATTRS common::optional<std::int64_t> EffectiveRecordLength() const {
     // When an input record is longer than an explicit RECL= from OPEN
     // it is effectively truncated on input.
     return openRecl && recordLength && *openRecl < *recordLength ? openRecl
                                                                  : recordLength;
   }
 
-  Fortran::common::optional<std::int64_t> recordLength;
+  common::optional<std::int64_t> recordLength;
 
   std::int64_t currentRecordNumber{1}; // 1 is first
 
@@ -106,12 +105,11 @@ struct ConnectionState : public ConnectionAttributes {
   std::int64_t furthestPositionInRecord{0}; // max(position+bytes)
 
   // Set at end of non-advancing I/O data transfer
-  Fortran::common::optional<std::int64_t>
-      leftTabLimit; // offset in current record
+  common::optional<std::int64_t> leftTabLimit; // offset in current record
 
   // currentRecordNumber value captured after ENDFILE/REWIND/BACKSPACE statement
   // or an end-of-file READ condition on a sequential access file
-  Fortran::common::optional<std::int64_t> endfileRecordNumber;
+  common::optional<std::int64_t> endfileRecordNumber;
 
   // Mutable modes set at OPEN() that can be overridden in READ/WRITE & FORMAT
   MutableModes modes; // BLANK=, DECIMAL=, SIGN=, ROUND=, PAD=, DELIM=, kP

flang-rt/include/flang-rt/runtime/environment.h

@@ -31,7 +31,7 @@ RT_OFFLOAD_VAR_GROUP_END
 // External unformatted I/O data conversions
 enum class Convert { Unknown, Native, LittleEndian, BigEndian, Swap };
 
-RT_API_ATTRS Fortran::common::optional<Convert> GetConvertFromString(
+RT_API_ATTRS common::optional<Convert> GetConvertFromString(
     const char *, std::size_t);
 
 struct ExecutionEnvironment {

flang-rt/include/flang-rt/runtime/file.h

@@ -37,11 +37,10 @@ class OpenFile {
   void set_mayAsynchronous(bool yes) { mayAsynchronous_ = yes; }
   bool isTerminal() const { return isTerminal_; }
   bool isWindowsTextFile() const { return isWindowsTextFile_; }
-  Fortran::common::optional<FileOffset> knownSize() const { return knownSize_; }
+  common::optional<FileOffset> knownSize() const { return knownSize_; }
 
   bool IsConnected() const { return fd_ >= 0; }
-  void Open(OpenStatus, Fortran::common::optional<Action>, Position,
-      IoErrorHandler &);
+  void Open(OpenStatus, common::optional<Action>, Position, IoErrorHandler &);
   void Predefine(int fd);
   void Close(CloseStatus, IoErrorHandler &);
 
@@ -95,10 +94,10 @@ class OpenFile {
   bool mayWrite_{false};
   bool mayPosition_{false};
   bool mayAsynchronous_{false};
-  Fortran::common::optional<Position>
+  common::optional<Position>
       openPosition_; // from Open(); reset after positioning
   FileOffset position_{0};
-  Fortran::common::optional<FileOffset> knownSize_;
+  common::optional<FileOffset> knownSize_;
   bool isTerminal_{false};
   bool isWindowsTextFile_{false}; // expands LF to CR+LF on write
 

flang-rt/include/flang-rt/runtime/format-implementation.h

@@ -302,7 +302,7 @@ RT_API_ATTRS int FormatControl<CONTEXT>::CueUpNextDataEdit(
     }
   }
   while (true) {
-    Fortran::common::optional<int> repeat;
+    common::optional<int> repeat;
     bool unlimited{false};
     auto maybeReversionPoint{offset_};
     CharType ch{GetNextChar(context)};
@@ -498,8 +498,8 @@ RT_API_ATTRS int FormatControl<CONTEXT>::CueUpNextDataEdit(
 
 // Returns the next data edit descriptor
 template <typename CONTEXT>
-RT_API_ATTRS Fortran::common::optional<DataEdit>
-FormatControl<CONTEXT>::GetNextDataEdit(Context &context, int maxRepeat) {
+RT_API_ATTRS common::optional<DataEdit> FormatControl<CONTEXT>::GetNextDataEdit(
+    Context &context, int maxRepeat) {
   int repeat{CueUpNextDataEdit(context)};
   auto start{offset_};
   DataEdit edit;
@@ -530,7 +530,7 @@ FormatControl<CONTEXT>::GetNextDataEdit(Context &context, int maxRepeat) {
         }
         if (edit.ioTypeChars >= edit.maxIoTypeChars) {
           ReportBadFormat(context, "Excessive DT'iotype' in FORMAT", start);
-          return Fortran::common::nullopt;
+          return common::nullopt;
         }
         edit.ioType[edit.ioTypeChars++] = ch;
         if (ch == quote) {
@@ -539,7 +539,7 @@ FormatControl<CONTEXT>::GetNextDataEdit(Context &context, int maxRepeat) {
       }
       if (!ok) {
         ReportBadFormat(context, "Unclosed DT'iotype' in FORMAT", start);
-        return Fortran::common::nullopt;
+        return common::nullopt;
       }
     }
     if (PeekNext() == '(') {
@@ -554,7 +554,7 @@ FormatControl<CONTEXT>::GetNextDataEdit(Context &context, int maxRepeat) {
         }
         if (edit.vListEntries >= edit.maxVListEntries) {
           ReportBadFormat(context, "Excessive DT(v_list) in FORMAT", start);
-          return Fortran::common::nullopt;
+          return common::nullopt;
         }
         edit.vList[edit.vListEntries++] = n;
         auto ch{static_cast<char>(GetNextChar(context))};
@@ -565,7 +565,7 @@ FormatControl<CONTEXT>::GetNextDataEdit(Context &context, int maxRepeat) {
       }
       if (!ok) {
         ReportBadFormat(context, "Unclosed DT(v_list) in FORMAT", start);
-        return Fortran::common::nullopt;
+        return common::nullopt;
       }
     }
   } else { // not DT'iotype'

flang-rt/include/flang-rt/runtime/format.h

@@ -76,9 +76,9 @@ struct DataEdit {
   }
 
   char variation{'\0'}; // N, S, or X for EN, ES, EX; G/l for original G/list
-  Fortran::common::optional<int> width; // the 'w' field; optional for A
-  Fortran::common::optional<int> digits; // the 'm' or 'd' field
-  Fortran::common::optional<int> expoDigits; // 'Ee' field
+  common::optional<int> width; // the 'w' field; optional for A
+  common::optional<int> digits; // the 'm' or 'd' field
+  common::optional<int> expoDigits; // 'Ee' field
   MutableModes modes;
   int repeat{1};
 
@@ -116,7 +116,7 @@ template <typename CONTEXT> class FormatControl {
   // Extracts the next data edit descriptor, handling control edit descriptors
   // along the way.  If maxRepeat==0, this is a peek at the next data edit
   // descriptor.
-  RT_API_ATTRS Fortran::common::optional<DataEdit> GetNextDataEdit(
+  RT_API_ATTRS common::optional<DataEdit> GetNextDataEdit(
       Context &, int maxRepeat = 1);
 
   // Emit any remaining character literals after the last data item (on output)