fix some edge cases around multiline attributes

packages/autofmt/src/lib.rs

@@ -58,7 +58,7 @@ pub fn fmt_file(contents: &str) -> Vec<FormattedBlock> {
 
     let mut writer = Writer::new(contents);
 
-    // Dont parse nested macros
+    // Don't parse nested macros
     let mut end_span = LineColumn { column: 0, line: 0 };
     for item in macros {
         let macro_path = &item.path.segments[0].ident;
@@ -68,16 +68,11 @@ pub fn fmt_file(contents: &str) -> Vec<FormattedBlock> {
             continue;
         }
 
-        // item.parse_body::<CallBody>();
         let body = item.parse_body::<CallBody>().unwrap();
 
         let rsx_start = macro_path.span().start();
 
-        writer.out.indent = &writer.src[rsx_start.line - 1]
-            .chars()
-            .take_while(|c| *c == ' ')
-            .count()
-            / 4;
+        writer.out.indent = leading_whitespaces(&writer.src[rsx_start.line - 1]) / 4;
 
         write_body(&mut writer, &body);
 
@@ -230,3 +225,14 @@ pub(crate) fn write_ifmt(input: &IfmtInput, writable: &mut impl Write) -> std::f
     let display = DisplayIfmt(input);
     write!(writable, "{}", display)
 }
+
+pub fn leading_whitespaces(input: &str) -> usize {
+    input
+        .chars()
+        .map_while(|c| match c {
+            ' ' => Some(1),
+            '\t' => Some(4),
+            _ => None,
+        })
+        .sum()
+}