1 files changed, 0 insertions, 120 deletions
diff --git a/compiler/rustc_trait_selection/src/solve/search_graph/overflow.rs b/compiler/rustc_trait_selection/src/solve/search_graph/overflow.rs
deleted file mode 100644
index e0a2e0c5c..000000000
--- a/compiler/rustc_trait_selection/src/solve/search_graph/overflow.rs
+++ /dev/null
@@ -1,120 +0,0 @@
-use rustc_infer::infer::canonical::Canonical;
-use rustc_infer::traits::query::NoSolution;
-use rustc_middle::traits::solve::{Certainty, MaybeCause, QueryResult};
-use rustc_middle::ty::TyCtxt;
-use rustc_session::Limit;
-
-use super::SearchGraph;
-use crate::solve::{response_no_constraints, EvalCtxt};
-
-/// When detecting a solver overflow, we return ambiguity. Overflow can be
-/// *hidden* by either a fatal error in an **AND** or a trivial success in an **OR**.
-///
-/// This is in issue in case of exponential blowup, e.g. if each goal on the stack
-/// has multiple nested (overflowing) candidates. To deal with this, we reduce the limit
-/// used by the solver when hitting the default limit for the first time.
-///
-/// FIXME: Get tests where always using the `default_limit` results in a hang and refer
-/// to them here. We can also improve the overflow strategy if necessary.
-pub(super) struct OverflowData {
-    default_limit: Limit,
-    current_limit: Limit,
-    /// When proving an **AND** we have to repeatedly iterate over the yet unproven goals.
-    ///
-    /// Because of this each iteration also increases the depth in addition to the stack
-    /// depth.
-    additional_depth: usize,
-}
-
-impl OverflowData {
-    pub(super) fn new(tcx: TyCtxt<'_>) -> OverflowData {
-        let default_limit = tcx.recursion_limit();
-        OverflowData { default_limit, current_limit: default_limit, additional_depth: 0 }
-    }
-
-    #[inline]
-    pub(super) fn did_overflow(&self) -> bool {
-        self.default_limit.0 != self.current_limit.0
-    }
-
-    #[inline]
-    pub(super) fn has_overflow(&self, depth: usize) -> bool {
-        !self.current_limit.value_within_limit(depth + self.additional_depth)
-    }
-
-    /// Updating the current limit when hitting overflow.
-    fn deal_with_overflow(&mut self) {
-        // When first hitting overflow we reduce the overflow limit
-        // for all future goals to prevent hangs if there's an exponential
-        // blowup.
-        self.current_limit.0 = self.default_limit.0 / 8;
-    }
-}
-
-pub(in crate::solve) trait OverflowHandler<'tcx> {
-    fn search_graph(&mut self) -> &mut SearchGraph<'tcx>;
-
-    fn repeat_while_none<T>(
-        &mut self,
-        on_overflow: impl FnOnce(&mut Self) -> Result<T, NoSolution>,
-        mut loop_body: impl FnMut(&mut Self) -> Option<Result<T, NoSolution>>,
-    ) -> Result<T, NoSolution> {
-        let start_depth = self.search_graph().overflow_data.additional_depth;
-        let depth = self.search_graph().stack.len();
-        while !self.search_graph().overflow_data.has_overflow(depth) {
-            if let Some(result) = loop_body(self) {
-                self.search_graph().overflow_data.additional_depth = start_depth;
-                return result;
-            }
-
-            self.search_graph().overflow_data.additional_depth += 1;
-        }
-        self.search_graph().overflow_data.additional_depth = start_depth;
-        self.search_graph().overflow_data.deal_with_overflow();
-        on_overflow(self)
-    }
-
-    // Increment the `additional_depth` by one and evaluate `body`, or `on_overflow`
-    // if the depth is overflown.
-    fn with_incremented_depth<T>(
-        &mut self,
-        on_overflow: impl FnOnce(&mut Self) -> T,
-        body: impl FnOnce(&mut Self) -> T,
-    ) -> T {
-        let depth = self.search_graph().stack.len();
-        self.search_graph().overflow_data.additional_depth += 1;
-
-        let result = if self.search_graph().overflow_data.has_overflow(depth) {
-            self.search_graph().overflow_data.deal_with_overflow();
-            on_overflow(self)
-        } else {
-            body(self)
-        };
-
-        self.search_graph().overflow_data.additional_depth -= 1;
-        result
-    }
-}
-
-impl<'tcx> OverflowHandler<'tcx> for EvalCtxt<'_, 'tcx> {
-    fn search_graph(&mut self) -> &mut SearchGraph<'tcx> {
-        &mut self.search_graph
-    }
-}
-
-impl<'tcx> OverflowHandler<'tcx> for SearchGraph<'tcx> {
-    fn search_graph(&mut self) -> &mut SearchGraph<'tcx> {
-        self
-    }
-}
-
-impl<'tcx> SearchGraph<'tcx> {
-    pub fn deal_with_overflow(
-        &mut self,
-        tcx: TyCtxt<'tcx>,
-        goal: Canonical<'tcx, impl Sized>,
-    ) -> QueryResult<'tcx> {
-        self.overflow_data.deal_with_overflow();
-        response_no_constraints(tcx, goal, Certainty::Maybe(MaybeCause::Overflow))
-    }
-}