Index: include/clang/Basic/DiagnosticLexKinds.td
===================================================================
--- include/clang/Basic/DiagnosticLexKinds.td
+++ include/clang/Basic/DiagnosticLexKinds.td
@@ -403,7 +403,9 @@
 def err_pp_invalid_directive : Error<"invalid preprocessing directive">;
 def err_pp_directive_required : Error<
   "%0 must be used within a preprocessing directive">;
-def err_pp_file_not_found : Error<"'%0' file not found">, DefaultFatal;
+def err_pp_file_not_found : Error<
+  "'%0' file not found%select{|, possibly due to leading or trailing "
+  "non-alphanumeric characters in the file name}1">, DefaultFatal;
 def err_pp_through_header_not_found : Error<
   "'%0' required for precompiled header not found">, DefaultFatal;
 def err_pp_through_header_not_seen : Error<
Index: lib/Lex/PPDirectives.cpp
===================================================================
--- lib/Lex/PPDirectives.cpp
+++ lib/Lex/PPDirectives.cpp
@@ -1859,6 +1859,7 @@
       // If the file could not be located and it was included via angle
       // brackets, we can attempt a lookup as though it were a quoted path to
       // provide the user with a possible fixit.
+      bool isFileNotFoundLikelyTypo = false;
       if (isAngled) {
         File = LookupFile(
             FilenameLoc,
@@ -1868,16 +1869,27 @@
             Callbacks ? &RelativePath : nullptr, &SuggestedModule, &IsMapped);
         if (File) {
           SourceRange Range(FilenameTok.getLocation(), CharEnd);
-          Diag(FilenameTok, diag::err_pp_file_not_found_not_fatal) <<
-            Filename <<
-            FixItHint::CreateReplacement(Range, "\"" + Filename.str() + "\"");
+          Diag(FilenameTok, diag::err_pp_file_not_found_not_fatal)
+              << Filename
+              << FixItHint::CreateReplacement(Range,
+                                              "\"" + Filename.str() + "\"")
+              << isFileNotFoundLikelyTypo;
         }
       }
 
       // If the file is still not found, just go with the vanilla diagnostic
-      if (!File)
-        Diag(FilenameTok, diag::err_pp_file_not_found) << Filename
-                                                       << FilenameRange;
+      if (!File) {
+        // Assuming filename logically starts and end with alphnumeric
+        // character
+        if (!isAlphanumeric(Filename.front()) ||
+            !isAlphanumeric(Filename.back())) {
+          isFileNotFoundLikelyTypo = true;
+          Diag(FilenameTok, diag::err_pp_file_not_found)
+              << Filename << isFileNotFoundLikelyTypo;
+        }
+        Diag(FilenameTok, diag::err_pp_file_not_found)
+            << Filename << FilenameRange << isFileNotFoundLikelyTypo;
+      }
     }
   }
 
Index: lib/Lex/Pragma.cpp
===================================================================
--- lib/Lex/Pragma.cpp
+++ lib/Lex/Pragma.cpp
@@ -514,7 +514,7 @@
                  nullptr, CurDir, nullptr, nullptr, nullptr, nullptr);
   if (!File) {
     if (!SuppressIncludeNotFoundError)
-      Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+      Diag(FilenameTok, diag::err_pp_file_not_found) << Filename << 0;
     return;
   }
 
Index: test/Preprocessor/include-likely-typo.c
===================================================================
--- /dev/null
+++ test/Preprocessor/include-likely-typo.c
@@ -0,0 +1,2 @@
+// RUN: not %clang_cc1 -verify -frewrite-includes
+#include "<hello.h>" @expected-error {{'<hello.h>' file not found, possibly due to leading or trailing non-alphanumeric characters in the file name}}