alloc_statement
struct statement *stmt = alloc_statement(token->pos, STMT_COMPOUND);
struct statement *alloc_statement(struct position pos, int type);
struct statement *stmt = alloc_statement(expr->pos, STMT_COMPOUND);
struct statement *new = alloc_statement(stmt->pos, STMT_COMPOUND);
struct statement *dup = alloc_statement(stmt->pos, stmt->type);
struct statement *stmt = alloc_statement(expr->pos, STMT_COMPOUND);
struct statement *decl = alloc_statement(expr->pos, STMT_DECLARATION);
fn->stmt = alloc_statement(fn->pos, STMT_COMPOUND);
stmt = alloc_statement(expr->pos, STMT_EXPRESSION);
struct statement *stmt = alloc_statement(sym->pos, STMT_COMPOUND);
struct statement *stmt = alloc_statement(token->pos, STMT_NONE);
stmt = alloc_statement(token->pos, STMT_DECLARATION);
stmt = alloc_statement(token->pos, STMT_NONE);