diff --git a/src/compiler/c.rs b/src/compiler/c.rs
index 2badc6f71..1f753da1e 100644
--- a/src/compiler/c.rs
+++ b/src/compiler/c.rs
@@ -1448,6 +1448,26 @@ mod test {
         );
     }
 
+    #[test]
+    fn test_header_differs() {
+        let args = ovec!["a", "b", "c"];
+        const PREPROCESSED: &[u8] = b"hello world";
+        assert_neq!(
+            hash_key("abcd", Language::C,       &args, &[], &[], PREPROCESSED, false),
+            hash_key("abcd", Language::CHeader, &args, &[], &[], PREPROCESSED, false)
+        );
+    }
+
+    #[test]
+    fn test_plusplus_header_differs() {
+        let args = ovec!["a", "b", "c"];
+        const PREPROCESSED: &[u8] = b"hello world";
+        assert_neq!(
+            hash_key("abcd", Language::Cxx,       &args, &[], &[], PREPROCESSED, true),
+            hash_key("abcd", Language::CxxHeader, &args, &[], &[], PREPROCESSED, true)
+        );
+    }
+
     #[test]
     fn test_hash_key_executable_contents_differs() {
         let args = ovec!["a", "b", "c"];
diff --git a/src/compiler/compiler.rs b/src/compiler/compiler.rs
index a37d20775..812d34087 100644
--- a/src/compiler/compiler.rs
+++ b/src/compiler/compiler.rs
@@ -146,8 +146,10 @@ impl Language {
 
     pub fn as_str(self) -> &'static str {
         match self {
-            Language::C | Language::CHeader => "c",
-            Language::Cxx | Language::CxxHeader => "c++",
+            Language::C => "c",
+            Language::CHeader => "cHeader",
+            Language::Cxx => "c++",
+            Language::CxxHeader => "c++Header",
             Language::GenericHeader => "c/c++",
             Language::ObjectiveC => "objc",
             Language::ObjectiveCxx => "objc++",