Try to solve issue3456. (#3556)

tests/target/multiline_string_in_macro_def.rs

@@ -0,0 +1,14 @@
+macro_rules! assert_approx_eq {
+    ($a:expr, $b:expr, $eps:expr) => {{
+        let (a, b) = (&$a, &$b);
+        assert!(
+            (*a - *b).abs() < $eps,
+            "assertion failed: `(left !== right)` \
+             (left: `{:?}`, right: `{:?}`, expect diff: `{:?}`, real diff: `{:?}`)",
+            *a,
+            *b,
+            $eps,
+            (*a - *b).abs()
+        );
+    }};
+}

tests/target/should_not_format_string_when_format_strings_is_not_set.rs

@@ -0,0 +1,16 @@
+// format_strings is false by default.
+
+println!(
+    "DirEntry {{ \
+        binary_name: {:<64}, \
+        context_id: {:>2}, \
+        file_size: {:>6}, \
+        offset: 0x {:>08X}, \
+        actual_crc: 0x{:>08X} \
+    }}",
+    dir_entry.binary_name,
+    dir_entry.context_id,
+    dir_entry.file_size,
+    dir_entry.offset,
+    dir_entry.actual_crc
+);