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
@@ -94,6 +94,9 @@
     return;
   }
 
+  // Report the diagnostics from parsing
+  ci.parsing().messages().Emit(llvm::errs(), ci.allCookedSources());
+
   auto &parseTree{*ci.parsing().parseTree()};
 
   // Prepare semantics
diff --git a/flang/test/Frontend/preprocessor-diag.f90 b/flang/test/Frontend/preprocessor-diag.f90
deleted file mode 100644
--- a/flang/test/Frontend/preprocessor-diag.f90
+++ /dev/null
@@ -1,11 +0,0 @@
-! RUN: %f18 -E -I %S/Inputs/ %s 2>&1 | FileCheck %s
-! RUN: %flang-new -E -I %S/Inputs/ %s 2>&1 | FileCheck %s
-! RUN: %flang-new -fc1 -E -I %S/Inputs/ %s 2>&1 | FileCheck %s
-
-! Test that the driver correctly reports diagnostics from the prescanner. The contents of the include file are irrelevant here.
-
-! CHECK: preprocessor-diag.f90:8:20: #include: extra stuff ignored after file name
-#include <empty.h> comment
-! CHECK: preprocessor-diag.f90:10:20: #include: extra stuff ignored after file name
-#include "empty.h" comment
-end
diff --git a/flang/test/Frontend/prescanner-diag.f90 b/flang/test/Frontend/prescanner-diag.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Frontend/prescanner-diag.f90
@@ -0,0 +1,17 @@
+! Test that the driver correctly reports diagnostics from the prescanner. The contents of the include file are irrelevant here.
+
+! Test with -E (i.e. PrintPreprocessedAction, stops after prescanning)
+! RUN: %f18 -E -I %S/Inputs/ %s 2>&1 | FileCheck %s
+! RUN: %flang-new -E -I %S/Inputs/ %s 2>&1 | FileCheck %s
+! RUN: %flang-new -fc1 -E -I %S/Inputs/ %s 2>&1 | FileCheck %s
+
+! Test with -fsyntax-only (i.e. ParseSyntaxOnlyAction, stops after semantic checks)
+! RUN: %f18 -fparse-only -I %S/Inputs/ %s 2>&1 | FileCheck %s
+! RUN: %flang-new -fsyntax-only -I %S/Inputs/ %s 2>&1 | FileCheck %s
+! RUN: %flang-new -fc1 -fsyntax-only -I %S/Inputs/ %s 2>&1 | FileCheck %s
+
+! CHECK: prescanner-diag.f90:14:20: #include: extra stuff ignored after file name
+#include <empty.h> comment
+! CHECK: prescanner-diag.f90:16:20: #include: extra stuff ignored after file name
+#include "empty.h" comment
+end