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Tweak diagnostic

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This commit is contained in:
Nathan Whitaker 2020-08-18 19:37:50 -04:00
parent ce95122e95
commit 5643a0662a
2 changed files with 10 additions and 11 deletions
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10
compiler/rustc_lint/src/methods.rs
View File

@ -43,12 +43,13 @@ impl<'tcx> LateLintPass<'tcx> for TemporaryCStringAsPtr {
match first_method_call(expr) {
Some((path, args)) if path.ident.name == sym::as_ptr => {
let unwrap_arg = &args[0];
let as_ptr_span = path.ident.span;
match first_method_call(unwrap_arg) {
Some((path, args))
if path.ident.name == sym::unwrap || path.ident.name == sym::expect =>
{
let source_arg = &args[0];
lint_cstring_as_ptr(cx, source_arg, unwrap_arg);
lint_cstring_as_ptr(cx, as_ptr_span, source_arg, unwrap_arg);
}
_ => return,
}
@ -62,6 +63,7 @@ const CSTRING_PATH: [Symbol; 4] = [sym::std, sym::ffi, sym::c_str, sym::CString]
fn lint_cstring_as_ptr(
cx: &LateContext<'_>,
as_ptr_span: Span,
source: &rustc_hir::Expr<'_>,
unwrap: &rustc_hir::Expr<'_>,
) {
@ -70,11 +72,11 @@ fn lint_cstring_as_ptr(
if cx.tcx.is_diagnostic_item(sym::result_type, def.did) {
if let ty::Adt(adt, _) = substs.type_at(0).kind {
if cx.match_def_path(adt.did, &CSTRING_PATH) {
cx.struct_span_lint(TEMPORARY_CSTRING_AS_PTR, source.span, |diag| {
cx.struct_span_lint(TEMPORARY_CSTRING_AS_PTR, as_ptr_span, |diag| {
let mut diag = diag
.build("getting the inner pointer of a temporary `CString`");
diag.span_label(source.span, "this pointer will be invalid");
diag.span_help(
diag.span_label(as_ptr_span, "this pointer will be invalid");
diag.span_label(
unwrap.span,
"this `CString` is deallocated at the end of the expression, bind it to a variable to extend its lifetime",
);

11
src/test/ui/lint/lint-temporary-cstring-as-ptr.stderr
View File

@ -1,15 +1,12 @@
error: getting the inner pointer of a temporary `CString`
--> $DIR/lint-temporary-cstring-as-ptr.rs:6:13
--> $DIR/lint-temporary-cstring-as-ptr.rs:6:48
|
LL | let s = CString::new("some text").unwrap().as_ptr();
| ^^^^^^^^^^^^^^^^^^^^^^^^^ this pointer will be invalid
| ---------------------------------- ^^^^^^ this pointer will be invalid
| |
| this `CString` is deallocated at the end of the expression, bind it to a variable to extend its lifetime
|
= note: `#[deny(temporary_cstring_as_ptr)]` on by default
help: this `CString` is deallocated at the end of the expression, bind it to a variable to extend its lifetime
--> $DIR/lint-temporary-cstring-as-ptr.rs:6:13
|
LL | let s = CString::new("some text").unwrap().as_ptr();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: pointers do not have a lifetime; when calling `as_ptr` the `CString` is deallocated because nothing is referencing it as far as the type system is concerned
error: aborting due to previous error