[flang] Fix clang warning that crept into codebase over weekend

Original-commit: flang-compiler/f18@8c8ad4c0d8db06f5421cfeb5fe2529ed06fe53c9
Reviewed-on: https://github.com/flang-compiler/f18/pull/406

diff --git a/flang/lib/semantics/tools.h b/flang/lib/semantics/tools.h
index d434350..b3eb1e2 100644 (file)
--- a/flang/lib/semantics/tools.h
+++ b/flang/lib/semantics/tools.h
@@ -29,7 +29,7 @@ struct Variable;
 }
 
 namespace Fortran::evaluate {
-class GenericExprWrapper;
+struct GenericExprWrapper;
 }
 
 namespace Fortran::semantics {