diff --git a/src/macros.rs b/src/macros.rs
index 16897e57dcb..eed6238acfc 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -256,7 +256,8 @@ fn rewrite_macro_inner(
         }
     };
 
-    if !arg_vec.is_empty() && arg_vec.iter().all(MacroArg::is_item) {
+    let has_item = arg_vec.iter().any(MacroArg::is_item);
+    if has_item && arg_vec.iter().all(MacroArg::is_item) {
         return rewrite_macro_with_items(
             context,
             &arg_vec,
@@ -268,6 +269,9 @@ fn rewrite_macro_inner(
             mac.span(),
         );
     }
+    if has_item {
+        return return_macro_parse_failure_fallback(context, shape.indent, position, mac.span());
+    }
 
     match style {
         Delimiter::Parenthesis => {
diff --git a/tests/source/issue-6629.rs b/tests/source/issue-6629.rs
new file mode 100644
index 00000000000..1ed9927f132
--- /dev/null
+++ b/tests/source/issue-6629.rs
@@ -0,0 +1,13 @@
+macro_rules! reproduce {
+    (type Fail = $ty:ty; arr = $($arr:expr),+) => {
+        ( vec![$($arr),+] )
+    };
+    ( $expr:expr, $($arr:item),+) => {
+        1
+    };
+}
+
+fn main() {
+    reproduce!(type Fail = char; arr = 1);
+    reproduce!(23, type Fail = char;, type Fail = char;);
+}
diff --git a/tests/target/issue-6629.rs b/tests/target/issue-6629.rs
new file mode 100644
index 00000000000..1ed9927f132
--- /dev/null
+++ b/tests/target/issue-6629.rs
@@ -0,0 +1,13 @@
+macro_rules! reproduce {
+    (type Fail = $ty:ty; arr = $($arr:expr),+) => {
+        ( vec![$($arr),+] )
+    };
+    ( $expr:expr, $($arr:item),+) => {
+        1
+    };
+}
+
+fn main() {
+    reproduce!(type Fail = char; arr = 1);
+    reproduce!(23, type Fail = char;, type Fail = char;);
+}