gives up on a `box` pattern

The following expression:

matches!(stmt, ast::Stmt{kind: ast::StmtKind::MacCall(box ast::MacCallStmt {style : ast::MacStmtStyle::Braces,..}),..})

refuses to get formatted (line formatted, but exceeded maximum width).

Whereas if I remove the box, it gets formatted just fine:

matches!(
    stmt,
    ast::Stmt {
        kind: ast::StmtKind::MacCall(ast::MacCallStmt {
            style: ast::MacStmtStyle::Braces,
            ..
        }),
        ..
    }
)

(I've never touched rustfmt source code before, but I could try working on this, with some help)

Start by running rustfmt on the reported matches! expression and compare it with the version without box. Trace the formatting path for Rust patterns, then verify that the box form formats successfully without exceeding the maximum width while preserving the expected structure.