diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -61,6 +61,9 @@
     return;
   }
 
+  // Print diagnostics from the preprocessor
+  ci.parsing().messages().Emit(llvm::errs(), ci.allCookedSources());
+
   // Create a file and save the preprocessed output there
   if (auto os{ci.CreateDefaultOutputFile(
           /*Binary=*/true, /*InFile=*/GetCurrentFileOrBufferName())}) {
diff --git a/flang/test/Frontend/Inputs/empty.h b/flang/test/Frontend/Inputs/empty.h
new file mode 100644
diff --git a/flang/test/Frontend/preprocessor-diag.f90 b/flang/test/Frontend/preprocessor-diag.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Frontend/preprocessor-diag.f90
@@ -0,0 +1,11 @@
+! RUN: %f18 -E -I %S/Inputs/ %s 2>&1 | FileCheck %s --check-prefix=ERROR
+! RUN: %flang-new -E -I %S/Inputs/ %s 2>&1 | FileCheck %s --check-prefix=ERROR
+! RUN: %flang-new -fc1 -E -I %S/Inputs/ %s 2>&1 | FileCheck %s --check-prefix=ERROR
+
+! Test that the driver correctly reports diagnostics from the prescanner. The contents of the include file are irrelevant here.
+
+! ERROR: :8:20: #include: extra stuff ignored after file name
+#include <empty.h> comment
+! ERROR: :10:20: #include: extra stuff ignored after file name
+#include "empty.h" comment
+end