[flang-commits] [flang] [flang][OpenMP] Catch threadprivate common block vars that appear in equivalence (PR #127642)

[Kiran Chandramohan via flang-commits]

================
@@ -1479,7 +1479,22 @@ void OmpStructureChecker::CheckThreadprivateOrDeclareTargetVar(
                 }
               }
             },
-            [&](const parser::Name &) {}, // common block
+            [&](const parser::Name &name) {
+              if (!name.symbol) {
+                return;
+              }
+              if (auto *cb{name.symbol->detailsIf<CommonBlockDetails>()}) {
+                for (const auto &obj : cb->objects()) {
+                  if (FindEquivalenceSet(*obj)) {
+                    context_.Say(name.source,
+                        "A variable in a %s directive cannot appear in an EQUIVALENCE statement"
+                        " (variable '%s' from common block '/%s/')"_err_en_US,
+                        ContextDirectiveAsFortran(), obj->name(),
+                        name.symbol->name());
+                  }
+                }
+              }
----------------
kiranchandramohan wrote:

Nit: The frontend style is to nest 
```
if (name.symbol) {
   if (auto *cb{name.symbol->detailsIf<CommonBlockDetails>()}) {
              ....
   }
}
```

https://github.com/llvm/llvm-project/pull/127642