rust/clippy_lints/src/panic_unimplemented.rs
2019-01-24 20:32:18 +01:00

104 lines
3.4 KiB
Rust

use crate::utils::{is_direct_expn_of, is_expn_of, match_def_path, opt_def_id, paths, resolve_node, span_lint};
use if_chain::if_chain;
use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::{declare_tool_lint, lint_array};
use syntax::ast::LitKind;
use syntax::ptr::P;
use syntax_pos::Span;
/// **What it does:** Checks for missing parameters in `panic!`.
///
/// **Why is this bad?** Contrary to the `format!` family of macros, there are
/// two forms of `panic!`: if there are no parameters given, the first argument
/// is not a format string and used literally. So while `format!("{}")` will
/// fail to compile, `panic!("{}")` will not.
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// panic!("This `panic!` is probably missing a parameter there: {}");
/// ```
declare_clippy_lint! {
pub PANIC_PARAMS,
style,
"missing parameters in `panic!` calls"
}
/// **What it does:** Checks for usage of `unimplemented!`.
///
/// **Why is this bad?** This macro should not be present in production code
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// unimplemented!();
/// ```
declare_clippy_lint! {
pub UNIMPLEMENTED,
restriction,
"`unimplemented!` should not be present in production code"
}
pub struct Pass;
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(PANIC_PARAMS, UNIMPLEMENTED)
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if_chain! {
if let ExprKind::Block(ref block, _) = expr.node;
if let Some(ref ex) = block.expr;
if let ExprKind::Call(ref fun, ref params) = ex.node;
if let ExprKind::Path(ref qpath) = fun.node;
if let Some(fun_def_id) = opt_def_id(resolve_node(cx, qpath, fun.hir_id));
if match_def_path(cx.tcx, fun_def_id, &paths::BEGIN_PANIC);
if params.len() == 2;
then {
if is_expn_of(expr.span, "unimplemented").is_some() {
let span = get_outer_span(expr);
span_lint(cx, UNIMPLEMENTED, span,
"`unimplemented` should not be present in production code");
} else {
match_panic(params, expr, cx);
}
}
}
}
}
fn get_outer_span(expr: &Expr) -> Span {
if_chain! {
if let Some(first) = expr.span.ctxt().outer().expn_info();
if let Some(second) = first.call_site.ctxt().outer().expn_info();
then {
second.call_site
} else {
expr.span
}
}
}
fn match_panic(params: &P<[Expr]>, expr: &Expr, cx: &LateContext<'_, '_>) {
if_chain! {
if let ExprKind::Lit(ref lit) = params[0].node;
if is_direct_expn_of(expr.span, "panic").is_some();
if let LitKind::Str(ref string, _) = lit.node;
let string = string.as_str().replace("{{", "").replace("}}", "");
if let Some(par) = string.find('{');
if string[par..].contains('}');
if params[0].span.source_callee().is_none();
if params[0].span.lo() != params[0].span.hi();
then {
span_lint(cx, PANIC_PARAMS, params[0].span,
"you probably are missing some parameter in your format string");
}
}
}