move considering_regions to the infcx

compiler/rustc_infer/src/infer/at.rs

@@ -65,6 +65,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         Self {
             tcx: self.tcx,
             defining_use_anchor: self.defining_use_anchor,
+            considering_regions: self.considering_regions,
             in_progress_typeck_results: self.in_progress_typeck_results,
             inner: self.inner.clone(),
             skip_leak_check: self.skip_leak_check.clone(),

compiler/rustc_infer/src/infer/mod.rs

@@ -265,6 +265,11 @@ pub struct InferCtxt<'a, 'tcx> {
     /// might come up during inference or typeck.
     pub defining_use_anchor: DefiningAnchor,
 
+    /// Whether this inference context should care about region obligations in
+    /// the root universe. Most notably, this is used during hir typeck as region
+    /// solving is left to borrowck instead.
+    pub considering_regions: bool,
+
     /// During type-checking/inference of a body, `in_progress_typeck_results`
     /// contains a reference to the typeck results being built up, which are
     /// used for reading closure kinds/signatures as they are inferred,
@@ -539,8 +544,9 @@ impl<'tcx> fmt::Display for FixupError<'tcx> {
 /// without using `Rc` or something similar.
 pub struct InferCtxtBuilder<'tcx> {
     tcx: TyCtxt<'tcx>,
-    fresh_typeck_results: Option<RefCell<ty::TypeckResults<'tcx>>>,
     defining_use_anchor: DefiningAnchor,
+    considering_regions: bool,
+    fresh_typeck_results: Option<RefCell<ty::TypeckResults<'tcx>>>,
 }
 
 pub trait TyCtxtInferExt<'tcx> {
@@ -552,6 +558,7 @@ impl<'tcx> TyCtxtInferExt<'tcx> for TyCtxt<'tcx> {
         InferCtxtBuilder {
             tcx: self,
             defining_use_anchor: DefiningAnchor::Error,
+            considering_regions: true,
             fresh_typeck_results: None,
         }
     }
@@ -577,6 +584,11 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
         self
     }
 
+    pub fn ignoring_regions(mut self) -> Self {
+        self.considering_regions = false;
+        self
+    }
+
     /// Given a canonical value `C` as a starting point, create an
     /// inference context that contains each of the bound values
     /// within instantiated as a fresh variable. The `f` closure is
@@ -601,11 +613,17 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
     }
 
     pub fn enter<R>(&mut self, f: impl for<'a> FnOnce(InferCtxt<'a, 'tcx>) -> R) -> R {
-        let InferCtxtBuilder { tcx, defining_use_anchor, ref fresh_typeck_results } = *self;
+        let InferCtxtBuilder {
+            tcx,
+            defining_use_anchor,
+            considering_regions,
+            ref fresh_typeck_results,
+        } = *self;
         let in_progress_typeck_results = fresh_typeck_results.as_ref();
         f(InferCtxt {
             tcx,
             defining_use_anchor,
+            considering_regions,
             in_progress_typeck_results,
             inner: RefCell::new(InferCtxtInner::new()),
             lexical_region_resolutions: RefCell::new(None),