nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2024-11-25 16:24:46 +00:00
Code Issues Packages Projects Releases Wiki Activity

Multiple candidates with same response is not ambiguous

Browse Source
This commit is contained in:
Michael Goulet 2023-02-09 18:14:13 +00:00
parent 8996ea93b6
commit 3c4e1f85cb
5 changed files with 8 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Cargo.lock
View File

@ -4773,6 +4773,7 @@ checksum = "8ba09476327c4b70ccefb6180f046ef588c26a24cf5d269a9feba316eb4f029f"
name = "rustc_trait_selection" name = "rustc_trait_selection"
version = "0.0.0" version = "0.0.0"
dependencies = [ dependencies = [
"itertools",
"rustc_ast", "rustc_ast",
"rustc_attr", "rustc_attr",
"rustc_data_structures", "rustc_data_structures",

1
compiler/rustc_trait_selection/Cargo.toml
View File

@ -24,3 +24,4 @@ rustc_span = { path = "../rustc_span" }
rustc_target = { path = "../rustc_target" } rustc_target = { path = "../rustc_target" }
rustc_transmute = { path = "../rustc_transmute", features = ["rustc"] } rustc_transmute = { path = "../rustc_transmute", features = ["rustc"] }
smallvec = { version = "1.8.1", features = ["union", "may_dangle"] } smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
itertools = "0.10.1"

8
compiler/rustc_trait_selection/src/solve/assembly.rs
View File

@ -4,6 +4,7 @@ use super::infcx_ext::InferCtxtExt;
#[cfg(doc)] #[cfg(doc)]
use super::trait_goals::structural_traits::*; use super::trait_goals::structural_traits::*;
use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, MaybeCause, QueryResult}; use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
use itertools::Itertools;
use rustc_hir::def_id::DefId; use rustc_hir::def_id::DefId;
use rustc_infer::traits::query::NoSolution; use rustc_infer::traits::query::NoSolution;
use rustc_infer::traits::util::elaborate_predicates; use rustc_infer::traits::util::elaborate_predicates;
@ -489,9 +490,9 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
i += 1; i += 1;
} }
// If there are *STILL* multiple candidates, give up // If there are *STILL* multiple candidates that have *different* response
// and report ambiguity. // results, give up and report ambiguity.
if candidates.len() > 1 { if candidates.len() > 1 && !candidates.iter().map(|cand| cand.result).all_equal() {
let certainty = if candidates.iter().all(|x| { let certainty = if candidates.iter().all(|x| {
matches!(x.result.value.certainty, Certainty::Maybe(MaybeCause::Overflow)) matches!(x.result.value.certainty, Certainty::Maybe(MaybeCause::Overflow))
}) { }) {
@ -503,6 +504,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
} }
} }
// FIXME: What if there are >1 candidates left with the same response, and one is a reservation impl?
Ok(self.discard_reservation_impl(candidates.pop().unwrap()).result) Ok(self.discard_reservation_impl(candidates.pop().unwrap()).result)
} }

2
tests/ui/traits/new-solver/provisional-result-done.rs
View File

@ -1,5 +1,5 @@
// known-bug: unknown
// compile-flags: -Ztrait-solver=next // compile-flags: -Ztrait-solver=next
// check-pass
// This tests checks that we update results in the provisional cache when // This tests checks that we update results in the provisional cache when
// we pop a goal from the stack. // we pop a goal from the stack.

11
tests/ui/traits/new-solver/provisional-result-done.stderr
View File

@ -1,11 +0,0 @@
error[E0283]: type annotations needed: cannot satisfy `Bar<T>: Coinductive`
--> $DIR/provisional-result-done.rs:16:25
|
LL | impl<T> Coinductive for Bar<T>
| ^^^^^^
|
= note: cannot satisfy `Bar<T>: Coinductive`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0283`.