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Improve non_fmt_panics suggestion based on trait impls.

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This commit is contained in:
Mara Bos 2021-08-16 17:25:35 +02:00
parent 23461b210f
commit 0a313250a4
3 changed files with 54 additions and 12 deletions
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1
Cargo.lock
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@ -3932,6 +3932,7 @@ dependencies = [
"rustc_feature",
"rustc_hir",
"rustc_index",
"rustc_infer",
"rustc_middle",
"rustc_parse_format",
"rustc_serialize",

1
compiler/rustc_lint/Cargo.toml
View File

@ -21,3 +21,4 @@ rustc_session = { path = "../rustc_session" }
rustc_serialize = { path = "../rustc_serialize" }
rustc_trait_selection = { path = "../rustc_trait_selection" }
rustc_parse_format = { path = "../rustc_parse_format" }
rustc_infer = { path = "../rustc_infer" }

64
compiler/rustc_lint/src/non_fmt_panic.rs
View File

@ -2,12 +2,15 @@ use crate::{LateContext, LateLintPass, LintContext};
use rustc_ast as ast;
use rustc_errors::{pluralize, Applicability};
use rustc_hir as hir;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty;
use rustc_middle::ty::subst::InternalSubsts;
use rustc_parse_format::{ParseMode, Parser, Piece};
use rustc_session::lint::FutureIncompatibilityReason;
use rustc_span::edition::Edition;
use rustc_span::{hygiene, sym, symbol::kw, symbol::SymbolStr, InnerSpan, Span, Symbol};
use rustc_trait_selection::infer::InferCtxtExt;
declare_lint! {
/// The `non_fmt_panics` lint detects `panic!(..)` invocations where the first
@ -129,20 +132,57 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
ty.ty_adt_def(),
Some(ty_def) if cx.tcx.is_diagnostic_item(sym::string_type, ty_def.did),
);
l.span_suggestion_verbose(
arg_span.shrink_to_lo(),
"add a \"{}\" format string to Display the message",
"\"{}\", ".into(),
if is_str {
Applicability::MachineApplicable
} else {
Applicability::MaybeIncorrect
},
);
if !is_str && panic == sym::std_panic_macro {
let (suggest_display, suggest_debug) = cx.tcx.infer_ctxt().enter(|infcx| {
let display = is_str || cx.tcx.get_diagnostic_item(sym::display_trait).map(|t| {
infcx.type_implements_trait(t, ty, InternalSubsts::empty(), cx.param_env).may_apply()
}) == Some(true);
let debug = !display && cx.tcx.get_diagnostic_item(sym::debug_trait).map(|t| {
infcx.type_implements_trait(t, ty, InternalSubsts::empty(), cx.param_env).may_apply()
}) == Some(true);
(display, debug)
});
let suggest_panic_any = !is_str && panic == sym::std_panic_macro;
let fmt_applicability = if suggest_panic_any {
// If we can use panic_any, use that as the MachineApplicable suggestion.
Applicability::MaybeIncorrect
} else {
// If we don't suggest panic_any, using a format string is our best bet.
Applicability::MachineApplicable
};
if suggest_display {
l.span_suggestion_verbose(
arg_span.shrink_to_lo(),
"add a \"{}\" format string to Display the message",
"\"{}\", ".into(),
fmt_applicability,
);
} else if suggest_debug {
l.span_suggestion_verbose(
arg_span.shrink_to_lo(),
&format!(
"add a \"{{:?}}\" format string to use the Debug implementation of `{}`",
ty,
),
"\"{:?}\", ".into(),
fmt_applicability,
);
}
if suggest_panic_any {
if let Some((open, close, del)) = find_delimiters(cx, span) {
l.multipart_suggestion(
"or use std::panic::panic_any instead",
&format!(
"{}use std::panic::panic_any instead",
if suggest_display || suggest_debug {
"or "
} else {
""
},
),
if del == '(' {
vec![(span.until(open), "std::panic::panic_any".into())]
} else {