use crate::consts::{constant, Constant};
-use crate::utils::paths;
-use crate::utils::{is_direct_expn_of, is_expn_of, match_def_path, span_help_and_lint, snippet};
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::source::snippet_opt;
+use clippy_utils::{is_direct_expn_of, is_expn_of, match_panic_call};
use if_chain::if_chain;
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
-use syntax::ast::LitKind;
-use std::borrow::Cow;
+use rustc_hir::{Expr, ExprKind, UnOp};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
/// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls.
///
/// **Why is this bad?** Will be optimized out by the compiler or should probably be replaced by a
- /// panic!() or unreachable!()
+ /// `panic!()` or `unreachable!()`
///
/// **Known problems:** None
///
/// **Example:**
/// ```rust,ignore
/// assert!(false)
- /// // or
/// assert!(true)
- /// // or
/// const B: bool = false;
/// assert!(B)
/// ```
declare_lint_pass!(AssertionsOnConstants => [ASSERTIONS_ON_CONSTANTS]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
- let lint_assert_cb = |is_debug_assert: bool| {
- if let ExprKind::Unary(_, ref lit) = e.kind {
- if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.tables, lit) {
- if is_true {
- span_help_and_lint(
- cx,
- ASSERTIONS_ON_CONSTANTS,
- e.span,
- "`assert!(true)` will be optimized out by the compiler",
- "remove it",
- );
- } else if !is_debug_assert {
- span_help_and_lint(
- cx,
- ASSERTIONS_ON_CONSTANTS,
- e.span,
- "`assert!(false)` should probably be replaced",
- "use `panic!()` or `unreachable!()`",
- );
- }
- }
- }
+impl<'tcx> LateLintPass<'tcx> for AssertionsOnConstants {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+ let lint_true = |is_debug: bool| {
+ span_lint_and_help(
+ cx,
+ ASSERTIONS_ON_CONSTANTS,
+ e.span,
+ if is_debug {
+ "`debug_assert!(true)` will be optimized out by the compiler"
+ } else {
+ "`assert!(true)` will be optimized out by the compiler"
+ },
+ None,
+ "remove it",
+ );
};
+ let lint_false_without_message = || {
+ span_lint_and_help(
+ cx,
+ ASSERTIONS_ON_CONSTANTS,
+ e.span,
+ "`assert!(false)` should probably be replaced",
+ None,
+ "use `panic!()` or `unreachable!()`",
+ );
+ };
+ let lint_false_with_message = |panic_message: String| {
+ span_lint_and_help(
+ cx,
+ ASSERTIONS_ON_CONSTANTS,
+ e.span,
+ &format!("`assert!(false, {})` should probably be replaced", panic_message),
+ None,
+ &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;
}
- lint_assert_cb(true);
+ if_chain! {
+ if let ExprKind::Unary(_, ref lit) = e.kind;
+ if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.typeck_results(), lit);
+ if is_true;
+ then {
+ lint_true(true);
+ }
+ };
} else if let Some(assert_span) = is_direct_expn_of(e.span, "assert") {
if assert_span.from_expansion() {
return;
}
- if let Some((panic_message, is_true)) = assert_with_message(&cx, e) {
- if is_true {
- span_help_and_lint(
- cx,
- ASSERTIONS_ON_CONSTANTS,
- e.span,
- "`assert!(true)` will be optimized out by the compiler",
- "remove it",
- );
- } else if panic_message.is_empty() || panic_message.starts_with("\"assertion failed: ") {
- span_help_and_lint(
- cx,
- ASSERTIONS_ON_CONSTANTS,
- e.span,
- "`assert!(false)` should probably be replaced",
- "use `panic!()` or `unreachable!()`",
- );
- } else {
- 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(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(false),
+ 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, _)
-/// }
-/// }
-/// _ => { }
-/// };
+/// if !c {
+/// {
+/// ::std::rt::begin_panic(message, _)
+/// }
+/// }
/// ```
///
-/// where `message` is a string literal and `c` is a constant bool.
-///
-/// TODO extend this to match anything as message not just string literals
-///
-/// Returns the `message` argument of `begin_panic` and the value of `c` which is the
-/// first argument of `assert!`.
-fn assert_with_message<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) -> Option<(Cow<'a, str>, bool)> {
+/// where `message` is any expression and `c` is a constant bool.
+fn match_assert_with_message<'tcx>(cx: &LateContext<'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;
+ if let ExprKind::If(ref cond, ref then, _) = expr.kind;
+ if let ExprKind::Unary(UnOp::Not, ref expr) = cond.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((Constant::Bool(is_true), _)) = constant(cx, cx.typeck_results(), expr);
+ // block
+ if let ExprKind::Block(ref block, _) = then.kind;
+ if block.stmts.is_empty();
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;
+ // inner block is optional. unwrap it if it exists, or use the expression as is otherwise.
+ if let Some(begin_panic_call) = match block_expr.kind {
+ ExprKind::Block(ref inner_block, _) => &inner_block.expr,
+ _ => &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
- let panic_message_arg = snippet(cx, args[0].span, "..");
+ if let Some(args) = match_panic_call(cx, begin_panic_call);
+ if args.len() == 1;
+ // 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 {
- return Some((panic_message_arg, is_true));
+ // 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
}
-
-/// Matches a function call with the given path and returns the arguments.
-///
-/// Usage:
-///
-/// ```rust,ignore
-/// if let Some(args) = match_function_call(cx, begin_panic_call, &paths::BEGIN_PANIC);
-/// ```
-fn match_function_call<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, path: &[&str]) -> Option<&'a [Expr]> {
- if_chain! {
- if let ExprKind::Call(ref fun, ref args) = expr.kind;
- if let ExprKind::Path(ref qpath) = fun.kind;
- if let Some(fun_def_id) = cx.tables.qpath_res(qpath, fun.hir_id).opt_def_id();
- if match_def_path(cx, fun_def_id, path);
- then {
- return Some(&args)
- }
- };
- None
-}
projects / rust.git / blobdiff