[flang-commits] [flang] [flang] Fix sequence association for PARAMETER array elements (PR #187348)

[Eugene Epshteyn via flang-commits]

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@@ -5184,7 +5184,29 @@ MaybeExpr ArgumentAnalyzer::AnalyzeExprOrWholeAssumedSizeArray(
     }
   }
   auto restorer{context_.AllowNullPointer()};
-  return context_.Analyze(expr);
+  MaybeExpr result{context_.Analyze(expr)};
+  // If the expression is a subscripted named constant array (PARAMETER array
+  // element), preserve the Designator<ArrayRef> form rather than returning the
+  // folded scalar constant.  Sequence association requires a designator with
+  // an array element subscript (F'2023 15.5.2.5p14); constant folding of
+  // PARAMETER array elements loses this structure.
+  // Note: Analyze(expr) may have converted a FunctionReference to a Designator
+  // in the parse tree (via CheckFuncRefToArrayElement), so check for
+  // ArrayElement only after Analyze(expr) has run.
+  if (isProcedureCall_ && result && result->Rank() == 0) {
+    if (const auto *ae{parser::Unwrap<parser::ArrayElement>(expr)}) {
+      const auto &baseName{parser::GetLastName(ae->Base())};
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eugeneepshteyn wrote:

Thank you, I got confused between "rightmost Name" and "leftmost Name". 

I'll also add a test for `x%y(1)` case.

https://github.com/llvm/llvm-project/pull/187348