[flang] Emit just one warning for a bad format edit descriptor

[klausler]

Summary

An attempt to use an edit descriptor (other than A or L) in a FORMAT
statement without arequired 'w' width will elicit warnings from both
the parser and the I/O checker in semantics. Remove the warning from
the parser.

[clementval]

LGTM

flang/include/flang/Common/format.h

if (token_.kind() == TokenKind::UnsignedInteger) {
     if (wValue_ == 0 &&
         (*argString_ == 'A' || *argString_ == 'L' ||
             stmt_ == IoStmtKind::Read)) { // C1306, 13.7.2.1p6
       ReportError("'%s' edit descriptor 'w' value must be positive");
     }
     NextToken();
     return true;
   }
-  if (*argString_ != 'A') {
+  if (*argString_ != 'A' && *argString_ != 'L') {
     ReportWarning("Expected '%s' edit descriptor 'w' value"); // C1306
   }
   return false;
 }
 
 template <typename CHAR> void FormatValidator<CHAR>::check_m() {
   if (token_.kind() != TokenKind::Point) {
     return;

flang/lib/Parser/io-parsers.cpp

TYPE_PARSER(construct<format::IntrinsicTypeDataEditDesc>(
     construct<format::IntrinsicTypeDataEditDesc>(
         "G " >> pure(format::IntrinsicTypeDataEditDesc::Kind::G) ||
             "L " >> pure(format::IntrinsicTypeDataEditDesc::Kind::L),
         mandatoryWidth, noInt, noInt) ||
     construct<format::IntrinsicTypeDataEditDesc>(
         "A " >> pure(format::IntrinsicTypeDataEditDesc::Kind::A), maybe(width),
         noInt, noInt) ||
     // PGI/Intel extension: omitting width (and all else that follows)
-    extension<LanguageFeature::AbbreviatedEditDescriptor>(
-        "nonstandard usage: abbreviated edit descriptor"_port_en_US,
-        construct<format::IntrinsicTypeDataEditDesc>(
-            "I " >> pure(format::IntrinsicTypeDataEditDesc::Kind::I) ||
-                ("B "_tok / !letter /* don't occlude BN & BZ */) >>
-                    pure(format::IntrinsicTypeDataEditDesc::Kind::B) ||
-                "O " >> pure(format::IntrinsicTypeDataEditDesc::Kind::O) ||
-                "Z " >> pure(format::IntrinsicTypeDataEditDesc::Kind::Z) ||
-                "F " >> pure(format::IntrinsicTypeDataEditDesc::Kind::F) ||
-                ("D "_tok / !letter /* don't occlude DT, DC, & DP */) >>
-                    pure(format::IntrinsicTypeDataEditDesc::Kind::D) ||
-                "E " >>
-                    ("N " >>
-                            pure(format::IntrinsicTypeDataEditDesc::Kind::EN) ||
-                        "S " >>
-                            pure(format::IntrinsicTypeDataEditDesc::Kind::ES) ||
-                        "X " >>
-                            pure(format::IntrinsicTypeDataEditDesc::Kind::EX) ||
-                        pure(format::IntrinsicTypeDataEditDesc::Kind::E)) ||
-                "G " >> pure(format::IntrinsicTypeDataEditDesc::Kind::G) ||
-                "L " >> pure(format::IntrinsicTypeDataEditDesc::Kind::L),
-            noInt, noInt, noInt)))
+    // Parse them just to get them to the I/O checker in semantics;
+    // they are not supported by the runtime.
+    extension<LanguageFeature::AbbreviatedEditDescriptor>(construct<
+        format::IntrinsicTypeDataEditDesc>(
+                ("N " >> pure(format::IntrinsicTypeDataEditDesc::Kind::EN) ||
+                    "S " >> pure(format::IntrinsicTypeDataEditDesc::Kind::ES) ||
+                    "X " >> pure(format::IntrinsicTypeDataEditDesc::Kind::EX) ||
 
 // R1307 data-edit-desc (part 2 of 2)
 // R1312 v -> [sign] digit-string
 constexpr SignedDigitStringIgnoreSpaces scaleFactor;
 TYPE_PARSER(construct<format::DerivedTypeDataEditDesc>(
     "D T" >> defaulted(charLiteralConstantWithoutKind),
     defaulted(parenthesized(nonemptyList(scaleFactor)))))