func fixMerge(dst, src *cc.Expr) {
syn := dst.SyntaxInfo
syn.Comments.Before = append(syn.Comments.Before, src.Comments.Before...)
syn.Comments.After = append(syn.Comments.After, src.Comments.After...)
syn.Comments.Suffix = append(syn.Comments.Suffix, src.Comments.Suffix...)
*dst = *src
dst.SyntaxInfo = syn
}