+use crate::consts::{constant, Constant};
+use crate::utils::paths;
+use crate::utils::{is_direct_expn_of, is_expn_of, match_function_call, snippet_opt, span_help_and_lint};
use if_chain::if_chain;
-use rustc::hir::{Expr, ExprKind};
+use rustc::declare_lint_pass;
+use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
-use syntax_pos::Span;
-
-use crate::consts::{constant, Constant};
-use crate::utils::{in_macro_or_desugar, is_direct_expn_of, span_help_and_lint};
+use rustc_session::declare_tool_lint;
+use syntax::ast::LitKind;
declare_clippy_lint! {
/// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls.
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
- let mut is_debug_assert = false;
- let debug_assert_not_in_macro_or_desugar = |span: Span| {
- is_debug_assert = true;
- // Check that `debug_assert!` itself is not inside a macro
- !in_macro_or_desugar(span)
+ let lint_true = || {
+ span_help_and_lint(
+ cx,
+ ASSERTIONS_ON_CONSTANTS,
+ e.span,
+ "`assert!(true)` will be optimized out by the compiler",
+ "remove it",
+ );
+ };
+ let lint_false_without_message = || {
+ span_help_and_lint(
+ cx,
+ ASSERTIONS_ON_CONSTANTS,
+ e.span,
+ "`assert!(false)` should probably be replaced",
+ "use `panic!()` or `unreachable!()`",
+ );
};
- if_chain! {
- if let Some(assert_span) = is_direct_expn_of(e.span, "assert");
- if !in_macro_or_desugar(assert_span)
- || is_direct_expn_of(assert_span, "debug_assert")
- .map_or(false, debug_assert_not_in_macro_or_desugar);
- if let ExprKind::Unary(_, ref lit) = e.node;
- if let Some(bool_const) = constant(cx, cx.tables, lit);
- then {
- match bool_const.0 {
- Constant::Bool(true) => {
- span_help_and_lint(
- cx,
- ASSERTIONS_ON_CONSTANTS,
- e.span,
- "`assert!(true)` will be optimized out by the compiler",
- "remove it"
- );
- },
- Constant::Bool(false) if !is_debug_assert => {
- span_help_and_lint(
- cx,
- ASSERTIONS_ON_CONSTANTS,
- e.span,
- "`assert!(false)` should probably be replaced",
- "use `panic!()` or `unreachable!()`"
- );
- },
- _ => (),
+ let lint_false_with_message = |panic_message: String| {
+ span_help_and_lint(
+ cx,
+ ASSERTIONS_ON_CONSTANTS,
+ e.span,
+ &format!("`assert!(false, {})` should probably be replaced", panic_message),
+ &format!("use `panic!({})` or `unreachable!({})`", panic_message, panic_message),
+ )
+ };
+
+ if let Some(debug_assert_span) = is_expn_of(e.span, "debug_assert") {
+ if debug_assert_span.from_expansion() {
+ return;
+ }
+ if_chain! {
+ if let ExprKind::Unary(_, ref lit) = e.kind;
+ if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.tables, lit);
+ if is_true;
+ then {
+ lint_true();
}
+ };
+ } else if let Some(assert_span) = is_direct_expn_of(e.span, "assert") {
+ if assert_span.from_expansion() {
+ return;
}
+ if let Some(assert_match) = match_assert_with_message(&cx, e) {
+ match assert_match {
+ // matched assert but not message
+ AssertKind::WithoutMessage(false) => lint_false_without_message(),
+ AssertKind::WithoutMessage(true) | AssertKind::WithMessage(_, true) => lint_true(),
+ AssertKind::WithMessage(panic_message, false) => lint_false_with_message(panic_message),
+ };
+ }
+ }
+ }
+}
+
+/// Result of calling `match_assert_with_message`.
+enum AssertKind {
+ WithMessage(String, bool),
+ WithoutMessage(bool),
+}
+
+/// Check if the expression matches
+///
+/// ```rust,ignore
+/// match { let _t = !c; _t } {
+/// true => {
+/// {
+/// ::std::rt::begin_panic(message, _)
+/// }
+/// }
+/// _ => { }
+/// };
+/// ```
+///
+/// where `message` is any expression and `c` is a constant bool.
+fn match_assert_with_message<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) -> Option<AssertKind> {
+ if_chain! {
+ if let ExprKind::Match(ref expr, ref arms, _) = expr.kind;
+ // matches { let _t = expr; _t }
+ if let ExprKind::DropTemps(ref expr) = expr.kind;
+ if let ExprKind::Unary(UnOp::UnNot, ref expr) = expr.kind;
+ // bind the first argument of the `assert!` macro
+ if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.tables, expr);
+ // arm 1 pattern
+ if let PatKind::Lit(ref lit_expr) = arms[0].pat.kind;
+ if let ExprKind::Lit(ref lit) = lit_expr.kind;
+ if let LitKind::Bool(true) = lit.node;
+ // arm 1 block
+ if let ExprKind::Block(ref block, _) = arms[0].body.kind;
+ if block.stmts.len() == 0;
+ if let Some(block_expr) = &block.expr;
+ if let ExprKind::Block(ref inner_block, _) = block_expr.kind;
+ if let Some(begin_panic_call) = &inner_block.expr;
+ // function call
+ if let Some(args) = match_function_call(cx, begin_panic_call, &paths::BEGIN_PANIC);
+ if args.len() == 2;
+ // bind the second argument of the `assert!` macro if it exists
+ if let panic_message = snippet_opt(cx, args[0].span);
+ // second argument of begin_panic is irrelevant
+ // as is the second match arm
+ then {
+ // an empty message occurs when it was generated by the macro
+ // (and not passed by the user)
+ return panic_message
+ .filter(|msg| !msg.is_empty())
+ .map(|msg| AssertKind::WithMessage(msg, is_true))
+ .or(Some(AssertKind::WithoutMessage(is_true)));
}
}
+ None
}
projects / rust.git / blobdiff