[flang-commits] [flang] [Flang][Semantics] Diagnose missing MODULE prefix in submodule procedures (PR #197173)

[via flang-commits]

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@@ -5976,6 +5976,26 @@ const Symbol *SubprogramVisitor::CheckExtantProc(
 Symbol *SubprogramVisitor::PushSubprogramScope(const parser::Name &name,
     Symbol::Flag subpFlag, const parser::LanguageBindingSpec *bindingSpec,
     bool hasModulePrefix) {
+  if (!inInterfaceBlock() && currScope().IsSubmodule() && !hasModulePrefix) {
+    const Scope &parent{currScope().parent()};
+    if (parent.IsModule() || parent.IsSubmodule()) {
+      if (const Symbol *host{parent.FindSymbol(name.source)}) {
+        const Symbol &hostUlt{host->GetUltimate()};
+        const auto *hostSubp{hostUlt.detailsIf<SubprogramDetails>()};
+        if (hostSubp && hostSubp->isInterface() &&
+            hostUlt.attrs().test(Attr::MODULE)) {
+          context().messages().Warn(/*isInModuleFile=*/InModuleFile(),
+              context().languageFeatures(), common::UsageWarning::Portability,
+              name.source,
+              "Subprogram '%s' in this submodule is missing the MODULE prefix "
+              "to implement the module procedure interface from its parent; "
+              "did you mean 'MODULE %s'?"_port_en_US,
+              name.source,
+              subpFlag == Symbol::Flag::Subroutine ? "SUBROUTINE" : "FUNCTION");
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ShashwathiNavada wrote:

Done!

https://github.com/llvm/llvm-project/pull/197173