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use crate ::utils ::{ find_macro_calls , is_type_diagnostic_item , return_ty , span_lint_and_then } ;
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use rustc_hir as hir ;
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use rustc_hir ::intravisit ::FnKind ;
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use rustc_lint ::{ LateContext , LateLintPass } ;
use rustc_session ::{ declare_lint_pass , declare_tool_lint } ;
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use rustc_span ::{ sym , Span } ;
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `panic!`, `unimplemented!`, `todo!`, `unreachable!` or assertions in a function of type result.
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///
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/// **Why is this bad?** For some codebases, it is desirable for functions of type result to return an error instead of crashing. Hence panicking macros should be avoided.
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///
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/// **Known problems:** Functions called from a function returning a `Result` may invoke a panicking macro. This is not checked.
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///
/// **Example:**
///
/// ```rust
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/// fn result_with_panic() -> Result<bool, String>
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/// {
/// panic!("error");
/// }
/// ```
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/// Use instead:
/// ```rust
/// fn result_without_panic() -> Result<bool, String> {
/// Err(String::from("error"))
/// }
/// ```
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pub PANIC_IN_RESULT_FN ,
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restriction ,
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" functions of type `Result<..>` that contain `panic!()`, `todo!()`, `unreachable()`, `unimplemented()` or assertion "
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}
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declare_lint_pass! ( PanicInResultFn = > [ PANIC_IN_RESULT_FN ] ) ;
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impl < ' tcx > LateLintPass < ' tcx > for PanicInResultFn {
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fn check_fn (
& mut self ,
cx : & LateContext < ' tcx > ,
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fn_kind : FnKind < ' tcx > ,
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_ : & ' tcx hir ::FnDecl < ' tcx > ,
body : & ' tcx hir ::Body < ' tcx > ,
span : Span ,
hir_id : hir ::HirId ,
) {
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if ! matches! ( fn_kind , FnKind ::Closure ( _ ) )
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& & is_type_diagnostic_item ( cx , return_ty ( cx , hir_id ) , sym ::result_type )
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{
lint_impl_body ( cx , span , body ) ;
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}
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}
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}
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fn lint_impl_body < ' tcx > ( cx : & LateContext < ' tcx > , impl_span : Span , body : & ' tcx hir ::Body < ' tcx > ) {
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let panics = find_macro_calls (
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& [
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" unimplemented " ,
" unreachable " ,
" panic " ,
" todo " ,
" assert " ,
" assert_eq " ,
" assert_ne " ,
" debug_assert " ,
" debug_assert_eq " ,
" debug_assert_ne " ,
] ,
body ,
) ;
if ! panics . is_empty ( ) {
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span_lint_and_then (
cx ,
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PANIC_IN_RESULT_FN ,
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impl_span ,
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" used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result` " ,
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move | diag | {
diag . help (
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" `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing " ,
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) ;
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diag . span_note ( panics , " return Err() instead of panicking " ) ;
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} ,
) ;
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}
}