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Add a minimal working append_const_msg argument

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Deadbeef 2022-01-16 02:44:57 +08:00
parent fdf7d01088
commit 8b76cad0a7
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GPG key ID: 6D017A96D8E6C2F9
8 changed files with 112 additions and 22 deletions
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37
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View file

@ -310,13 +310,18 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
})
.unwrap_or_default();
let OnUnimplementedNote { message, label, note, enclosing_scope } =
self.on_unimplemented_note(trait_ref, &obligation);
let OnUnimplementedNote {
message,
label,
note,
enclosing_scope,
append_const_msg,
} = self.on_unimplemented_note(trait_ref, &obligation);
let have_alt_message = message.is_some() || label.is_some();
let is_try_conversion = self.is_try_conversion(span, trait_ref.def_id());
let is_unsize =
{ Some(trait_ref.def_id()) == self.tcx.lang_items().unsize_trait() };
let (message, note) = if is_try_conversion {
let (message, note, append_const_msg) = if is_try_conversion {
(
Some(format!(
"`?` couldn't convert the error to `{}`",
@ -327,9 +332,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
conversion on the error value using the `From` trait"
.to_owned(),
),
Some(None),
)
} else {
(message, note)
(message, note, append_const_msg)
};
let mut err = struct_span_err!(
@ -337,12 +343,27 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
span,
E0277,
"{}",
(!predicate_is_const).then(|| message).flatten().unwrap_or_else(
|| format!(
message
.and_then(|cannot_do_this| {
match (predicate_is_const, append_const_msg) {
// do nothing if predicate is not const
(false, _) => Some(cannot_do_this),
// suggested using default post message
(true, Some(None)) => {
Some(format!("{cannot_do_this} in const contexts"))
}
// overriden post message
(true, Some(Some(post_message))) => {
Some(format!("{cannot_do_this}{post_message}"))
}
// fallback to generic message
(true, None) => None,
}
})
.unwrap_or_else(|| format!(
"the trait bound `{}` is not satisfied{}",
trait_predicate, post_message,
)
)
))
);
if is_try_conversion {

21
compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
View file

@ -19,6 +19,7 @@ pub struct OnUnimplementedDirective {
pub label: Option<OnUnimplementedFormatString>,
pub note: Option<OnUnimplementedFormatString>,
pub enclosing_scope: Option<OnUnimplementedFormatString>,
pub append_const_msg: Option<Option<Symbol>>,
}
#[derive(Default)]
@ -27,6 +28,11 @@ pub struct OnUnimplementedNote {
pub label: Option<String>,
pub note: Option<String>,
pub enclosing_scope: Option<String>,
/// Append a message for `~const Trait` errors. `None` means not requested and
/// should fallback to a generic message, `Some(None)` suggests using the default
/// appended message, `Some(Some(s))` suggests use the `s` message instead of the
/// default one..
pub append_const_msg: Option<Option<Symbol>>,
}
fn parse_error(
@ -89,6 +95,7 @@ impl<'tcx> OnUnimplementedDirective {
let mut note = None;
let mut enclosing_scope = None;
let mut subcommands = vec![];
let mut append_const_msg = None;
let parse_value = |value_str| {
OnUnimplementedFormatString::try_parse(tcx, trait_def_id, value_str, span).map(Some)
@ -131,6 +138,14 @@ impl<'tcx> OnUnimplementedDirective {
}
continue;
}
} else if item.has_name(sym::append_const_msg) && append_const_msg.is_none() {
if let Some(msg) = item.value_str() {
append_const_msg = Some(Some(msg));
continue;
} else if item.is_word() {
append_const_msg = Some(None);
continue;
}
}
// nothing found
@ -153,6 +168,7 @@ impl<'tcx> OnUnimplementedDirective {
label,
note,
enclosing_scope,
append_const_msg,
})
}
}
@ -183,6 +199,7 @@ impl<'tcx> OnUnimplementedDirective {
)?),
note: None,
enclosing_scope: None,
append_const_msg: None,
}))
} else {
return Err(ErrorReported);
@ -201,6 +218,7 @@ impl<'tcx> OnUnimplementedDirective {
let mut label = None;
let mut note = None;
let mut enclosing_scope = None;
let mut append_const_msg = None;
info!("evaluate({:?}, trait_ref={:?}, options={:?})", self, trait_ref, options);
for command in self.subcommands.iter().chain(Some(self)).rev() {
@ -235,6 +253,8 @@ impl<'tcx> OnUnimplementedDirective {
if let Some(ref enclosing_scope_) = command.enclosing_scope {
enclosing_scope = Some(enclosing_scope_.clone());
}
append_const_msg = command.append_const_msg.clone();
}
let options: FxHashMap<Symbol, String> =
@ -244,6 +264,7 @@ impl<'tcx> OnUnimplementedDirective {
message: message.map(|m| m.format(tcx, trait_ref, &options)),
note: note.map(|n| n.format(tcx, trait_ref, &options)),
enclosing_scope: enclosing_scope.map(|e_s| e_s.format(tcx, trait_ref, &options)),
append_const_msg,
}
}
}