[flang-commits] [flang] Recognition of the Fortran 2023 ENUMERATION TYPE. (PR #185497)

[Peter Klausler via flang-commits]

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@@ -669,6 +669,34 @@ TYPE_PARSER(
 TYPE_PARSER(recovery("END ENUM"_tok, constructEndStmtErrorRecovery) >>
     construct<EndEnumStmt>())
 
+// R766 enumeration-type-def ->
+//        enumeration-type-stmt
+//        enumeration-enumerator-stmt [ enumeration-enumerator-stmt ]...
+//        end-enumeration-type-stmt
+TYPE_CONTEXT_PARSER("enumeration type definition"_en_US,
+    construct<EnumerationTypeDef>(statement(Parser<EnumerationTypeStmt>{}),
+        some(unambiguousStatement(Parser<EnumerationEnumeratorStmt>{})),
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klausler wrote:

`some` will fail if there are no enumerators, leading to a parse failure for the program.  If you use `many` instead, you can diagnose the error in semantics and fail more gracefully.

https://github.com/llvm/llvm-project/pull/185497