Fix bug: allow no- '_'-split binary format string, add test

clippy_lints/src/non_octal_unix_permissions.rs

@@ -50,10 +50,15 @@ fn check_binary_unix_permissions(lit_kind: &LitKind, snip: &str) -> bool {
 
         let group_sizes: Vec<usize> = num_lit.integer.split('_').map(str::len).collect();
         // check whether is binary format unix permissions
-        if group_sizes.len() != 3 && group_sizes.len() != 4 {
-            return false;
+        if group_sizes.len() == 1 && (num_lit.integer.len() == 9 || num_lit.integer.len() == 12) {
+            // 0bxxxxxxxxx or 0bxxxxxxxxxxxx
+            true
+        } else if group_sizes.len() == 3 || group_sizes.len() == 4 {
+            // 0bxxx_xxx_xxx or 0bxxx_xxx_xxx_xxx
+            group_sizes.iter().all(|len| *len == 3)
+        } else {
+            false
         }
-        group_sizes.iter().all(|len| *len == 3)
     } else {
         false
     }

tests/ui/non_octal_unix_permissions.fixed

@@ -25,9 +25,13 @@ fn main() {
 
     permissions.set_mode(0o644);
     permissions.set_mode(0o704);
+    // no error
+    permissions.set_mode(0b111_000_100);
 
     // DirBuilderExt::mode
     let mut builder = DirBuilder::new();
     builder.mode(0o755);
     builder.mode(0o406);
+    // no error
+    permissions.set_mode(0b111000100);
 }

tests/ui/non_octal_unix_permissions.rs

@@ -25,9 +25,13 @@ fn main() {
 
     permissions.set_mode(644);
     permissions.set_mode(0o704);
+    // no error
+    permissions.set_mode(0b111_000_100);
 
     // DirBuilderExt::mode
     let mut builder = DirBuilder::new();
     builder.mode(755);
     builder.mode(0o406);
+    // no error
+    permissions.set_mode(0b111000100);
 }

tests/ui/non_octal_unix_permissions.stderr

@@ -20,7 +20,7 @@ LL |     permissions.set_mode(644);
    |                          ^^^ help: consider using an octal literal instead: `0o644`
 
 error: using a non-octal value to set unix file permissions
-  --> $DIR/non_octal_unix_permissions.rs:31:18
+  --> $DIR/non_octal_unix_permissions.rs:33:18
    |
 LL |     builder.mode(755);
    |                  ^^^ help: consider using an octal literal instead: `0o755`