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Add message to replace assert!(false) help

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This commit is contained in:
Matthias Seiffert 2019-10-05 16:45:02 +02:00
parent 54bf4ffd62
commit 72a5d7b612
3 changed files with 106 additions and 9 deletions
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98
clippy_lints/src/assertions_on_constants.rs
View file

@ -1,9 +1,11 @@
use rustc::hir::{Expr, ExprKind};
use crate::consts::{constant, Constant};
use crate::utils::{is_direct_expn_of, is_expn_of, match_qpath, 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 crate::consts::{constant, Constant};
use crate::utils::{is_direct_expn_of, is_expn_of, span_help_and_lint};
use syntax::ast::LitKind;
use syntax::source_map::symbol::LocalInternedString;
declare_clippy_lint! {
/// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls.
@ -63,7 +65,93 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
if assert_span.from_expansion() {
return;
}
lint_assert_cb(false);
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.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,
),
);
}
}
}
}
}
// fn get_assert_args(snip: String) -> Option<Vec<String>> {
//
// }
fn assert_with_message<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) -> Option<(LocalInternedString, bool)> {
if_chain! {
if let ExprKind::Match(ref expr, ref arms, MatchSource::IfDesugar { contains_else_clause: false }) = expr.kind;
// match expr
if let ExprKind::DropTemps(ref expr) = expr.kind;
if let ExprKind::Unary(UnOp::UnNot, ref expr) = expr.kind;
//if let ExprKind::Lit(ref lit) = expr.kind;
if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.tables, expr);
//if is_true;
// match arms
// 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;
//if let LitKind::Bool(true) = lit1.node;
// arm 1 block
if let ExprKind::Block(ref block1, _) = arms[0].body.kind;
if let Some(trailing_expr1) = &block1.expr;
if block1.stmts.len() == 0;
//
if let ExprKind::Block(ref actual_block1, _) = trailing_expr1.kind;
if let Some(block1_expr) = &actual_block1.expr;
// function call
if let ExprKind::Call(ref func, ref args) = block1_expr.kind;
if let ExprKind::Path(ref path) = func.kind;
// ["{{root}}", "std", "rt", "begin_panic"] does not work
if match_qpath(path, &["$crate", "rt", "begin_panic"]);
// arguments
if args.len() == 2;
if let ExprKind::Lit(ref lit) = args[0].kind;
if let LitKind::Str(ref s, _) = lit.node;
let panic_message = s.as_str(); // bind the panic message
if let ExprKind::AddrOf(MutImmutable, ref inner) = args[1].kind;
if let ExprKind::Tup(ref elements) = inner.kind;
if elements.len() == 3;
if let ExprKind::Lit(ref lit1) = elements[0].kind;
if let LitKind::Str(ref s1, _) = lit1.node;
if let ExprKind::Lit(ref lit2) = elements[1].kind;
if let LitKind::Int(_, _) = lit2.node;
if let ExprKind::Lit(ref lit3) = elements[2].kind;
if let LitKind::Int(_, _) = lit3.node;
// arm 2 block
if let PatKind::Wild = arms[1].pat.kind;
if let ExprKind::Block(ref block2, _) = arms[1].body.kind;
if let None = &block2.expr;
if block2.stmts.len() == 0;
then {
return Some((panic_message, is_true));
}
}
return None;
}

1
tests/ui/assertions_on_constants.rs
View file

@ -16,6 +16,7 @@ fn main() {
const C: bool = false;
assert!(C);
assert!(C, "C message");
debug_assert!(true);
// Don't lint this, since there is no better way for expressing "Only panic in debug mode".

16
tests/ui/assertions_on_constants.stderr
View file

@ -23,13 +23,13 @@ LL | assert!(true, "true message");
|
= help: remove it
error: `assert!(false)` should probably be replaced
error: `assert!(false, "false message")` should probably be replaced
--> $DIR/assertions_on_constants.rs:12:5
|
LL | assert!(false, "false message");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: use `panic!()` or `unreachable!()`
= help: use `panic!("false message")` or `unreachable!("false message")`
error: `assert!(true)` will be optimized out by the compiler
--> $DIR/assertions_on_constants.rs:15:5
@ -47,8 +47,16 @@ LL | assert!(C);
|
= help: use `panic!()` or `unreachable!()`
error: `assert!(false, "C message")` should probably be replaced
--> $DIR/assertions_on_constants.rs:19:5
|
LL | assert!(C, "C message");
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: use `panic!("C message")` or `unreachable!("C message")`
error: `assert!(true)` will be optimized out by the compiler
--> $DIR/assertions_on_constants.rs:20:5
--> $DIR/assertions_on_constants.rs:21:5
|
LL | debug_assert!(true);
| ^^^^^^^^^^^^^^^^^^^^
@ -56,5 +64,5 @@ LL | debug_assert!(true);
= help: remove it
= note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
error: aborting due to 7 previous errors
error: aborting due to 8 previous errors