diff --git a/src/lib.rs b/src/lib.rs
index e8bd331f9680..80b0764e513e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -645,7 +645,7 @@ pub fn format_code_block(code_snippet: &str, config: &Config) -> Option<String>
     // then unindent the whole code block.
     let formatted = format_snippet(&snippet, config)?;
     // 2 = "}\n"
-    let block_len = formatted.len().checked_sub(2).unwrap_or(0);
+    let block_len = formatted.rfind('}').unwrap_or(formatted.len());
     let mut is_indented = true;
     for (kind, ref line) in LineClasses::new(&formatted[FN_MAIN_PREFIX.len()..block_len]) {
         if !is_first {
diff --git a/tests/config/issue-2641.toml b/tests/config/issue-2641.toml
new file mode 100644
index 000000000000..11c9dca8a06c
--- /dev/null
+++ b/tests/config/issue-2641.toml
@@ -0,0 +1 @@
+newline_style = "Windows"
diff --git a/tests/source/issue-2641.rs b/tests/source/issue-2641.rs
new file mode 100644
index 000000000000..c7ad60674fd5
--- /dev/null
+++ b/tests/source/issue-2641.rs
@@ -0,0 +1,3 @@
+macro_rules! a {
+    () => {{}}
+}
diff --git a/tests/target/issue-2641.rs b/tests/target/issue-2641.rs
new file mode 100644
index 000000000000..fbf5326c330d
--- /dev/null
+++ b/tests/target/issue-2641.rs
@@ -0,0 +1,3 @@
+macro_rules! a {
+    () => {{}};
+}