From 94d9b7ce604ff416a1902cd041f10f4c4a6e72bb Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval@gmail.com>
Date: Wed, 15 Mar 2023 17:35:00 +0100
Subject: [PATCH] [flang] Detect fir.class nested in fir.box as invalid element
 type

Catch invalid element type in fir.box in the verifier so
it does not propagate later in lowering.

Reviewed By: PeteSteinfeld

Differential Revision: https://reviews.llvm.org/D146078
---
 flang/lib/Optimizer/Dialect/FIRType.cpp | 2 ++
 flang/test/Fir/invalid-types.fir        | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/flang/lib/Optimizer/Dialect/FIRType.cpp b/flang/lib/Optimizer/Dialect/FIRType.cpp
index d9f703a679d4..c25c683b3e7d 100644
--- a/flang/lib/Optimizer/Dialect/FIRType.cpp
+++ b/flang/lib/Optimizer/Dialect/FIRType.cpp
@@ -456,6 +456,8 @@ static bool cannotBePointerOrHeapElementType(mlir::Type eleTy) {
 mlir::LogicalResult
 fir::BoxType::verify(llvm::function_ref<mlir::InFlightDiagnostic()> emitError,
                      mlir::Type eleTy) {
+  if (eleTy.isa<fir::BaseBoxType>())
+    return emitError() << "invalid element type\n";
   // TODO
   return mlir::success();
 }
diff --git a/flang/test/Fir/invalid-types.fir b/flang/test/Fir/invalid-types.fir
index 67360df27186..18bc9f7b4896 100644
--- a/flang/test/Fir/invalid-types.fir
+++ b/flang/test/Fir/invalid-types.fir
@@ -167,3 +167,8 @@ func.func private @oth3() -> !fir.vector<10:>
 
 // expected-error@+1 {{invalid element type}}
 func.func private @upe() -> !fir.class<!fir.box<i32>>
+
+// -----
+
+// expected-error@+1 {{invalid element type}}
+func.func private @upe() -> !fir.box<!fir.class<none>>