diff --git a/clang/include/clang/Basic/DiagnosticSerializationKinds.td b/clang/include/clang/Basic/DiagnosticSerializationKinds.td
index a1ae23a628021..3cb2cd32cf6d0 100644
--- a/clang/include/clang/Basic/DiagnosticSerializationKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSerializationKinds.td
@@ -62,7 +62,7 @@ def err_ast_file_out_of_date : Error<
   "%select{PCH|module|AST}0 file '%1' is out of date and "
   "needs to be rebuilt%select{|: %3}2">, DefaultFatal;
 def err_ast_file_invalid : Error<
-  "file '%1' is not a valid precompiled %select{PCH|module|AST}0 file">, DefaultFatal;
+  "file '%1' is not a valid precompiled %select{PCH|module|AST}0 file: %2">, DefaultFatal;
 def note_module_file_imported_by : Note<
   "imported by %select{|module '%2' in }1'%0'">;
 def err_module_file_not_module : Error<
diff --git a/clang/test/Modules/explicit-build.cpp b/clang/test/Modules/explicit-build.cpp
index 16eb604708c9d..7fca0082ea28a 100644
--- a/clang/test/Modules/explicit-build.cpp
+++ b/clang/test/Modules/explicit-build.cpp
@@ -161,7 +161,7 @@
 // RUN:            -fmodule-file=%t/not.pcm \
 // RUN:            %s 2>&1 | FileCheck --check-prefix=CHECK-BAD-FILE %s
 //
-// CHECK-BAD-FILE: fatal error: file '{{.*}}not.pcm' is not a valid precompiled module file
+// CHECK-BAD-FILE: fatal error: file '{{.*}}not.pcm' is not a valid precompiled module file: file too small to contain AST file magic
 
 // RUN: not %clang_cc1 -x c++ -std=c++11 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -Rmodule-build -fno-modules-error-recovery \
 // RUN:            -fmodule-file=%t/nonexistent.pcm \