[flang-commits] [flang] [flang][semantic] Implement semantic checks and new data structure (PR #203030)

[Eugene Epshteyn via flang-commits]

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@@ -343,11 +350,138 @@ void ArraySpecAnalyzer::Analyze(const parser::ExplicitShapeSpec &x) {
       std::get<parser::SpecificationExpr>(x.t));
 }
 
+std::optional<ArraySpecAnalyzer::ExplicitShapeBoundsResult>
+ArraySpecAnalyzer::checkExplicitShapeBoundsSpec(
+    const parser::ExplicitShapeBoundsSpec &x) {
+  const auto &lowerBoundOpt{std::get<0>(x.t)};
+  const auto &upperBound{std::get<1>(x.t)};
+
+  // Analyze, validate, fold, and wrap one bound expression in a Bound.
+  // Returns the Bound and, for rank-1, the constant extent; for scalar
+  // the extent is 0 (meaning "broadcast").
+  bool hasError{false};
+  auto analyzeBound =
+      [&](const auto &parseBound,
+          bool isUpper) -> std::optional<std::pair<Bound, std::int64_t>> {
+    MaybeExpr expr{AnalyzeExpr(context_, parseBound.thing)};
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eugeneepshteyn wrote:

`expr` is probably not going to be empty here, but let's add a check just in case and return `std::nullopt` if it is.

https://github.com/llvm/llvm-project/pull/203030