From 6ee8d751f63ab3652297aa88adafc6ca549cb899 Mon Sep 17 00:00:00 2001 From: Matthias Seiffert Date: Mon, 7 Oct 2019 22:08:00 +0200 Subject: [PATCH] Reduce duplication --- clippy_lints/src/assertions_on_constants.rs | 123 ++++++++++---------- 1 file changed, 59 insertions(+), 64 deletions(-) diff --git a/clippy_lints/src/assertions_on_constants.rs b/clippy_lints/src/assertions_on_constants.rs index 5bb57be00136..3f84f322500f 100644 --- a/clippy_lints/src/assertions_on_constants.rs +++ b/clippy_lints/src/assertions_on_constants.rs @@ -1,12 +1,11 @@ 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 crate::utils::{is_direct_expn_of, is_expn_of, match_def_path, snippet_opt, span_help_and_lint}; 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; declare_clippy_lint! { /// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls. @@ -34,72 +33,68 @@ 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!()`", - ); - } - } - } + 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!()`", + ); + }; + 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; } - lint_assert_cb(true); + 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((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(), + 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 @@ -113,13 +108,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants { /// }; /// ``` /// -/// 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<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) -> Option { if_chain! { if let ExprKind::Match(ref expr, ref arms, _) = expr.kind; // matches { let _t = expr; _t } @@ -140,12 +130,17 @@ fn assert_with_message<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx 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, ".."); + // 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