bjoernager/rust
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const eval errors: display the current item instance if there are generics involved

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This commit is contained in:
Rémy Rakic 2021-05-27 22:42:07 +02:00
parent 949aca6eeb
commit c31ca9a42c
9 changed files with 28 additions and 15 deletions
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18
compiler/rustc_mir/src/const_eval/eval_queries.rs
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@ -16,6 +16,7 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::{self, subst::Subst, TyCtxt};
use rustc_span::source_map::Span;
use rustc_target::abi::{Abi, LayoutOf};
use std::borrow::Cow;
use std::convert::TryInto;
pub fn note_on_undefined_behavior_error() -> &'static str {
@ -328,11 +329,22 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
))
} else {
let msg = if is_static {
"could not evaluate static initializer"
Cow::from("could not evaluate static initializer")
} else {
"evaluation of constant value failed"
// If the current item has generics, we'd like to enrich the message with the
// instance and its substs: to show the actual compile-time values, in addition to
// the expression, leading to the const eval error.
let instance = &key.value.instance;
if !instance.substs.is_empty() {
let instance = with_no_trimmed_paths(|| instance.to_string());
let msg = format!("evaluation of `{}` failed", instance);
Cow::from(msg)
} else {
Cow::from("evaluation of constant value failed")
}
};
Err(err.report_as_error(ecx.tcx.at(ecx.cur_span()), msg))
Err(err.report_as_error(ecx.tcx.at(ecx.cur_span()), &msg))
}
}
Ok(mplace) => {