diff --git a/compiler/rustc_borrowck/src/nll.rs b/compiler/rustc_borrowck/src/nll.rs
index d85af52b01e36..a47ac980eb0b8 100644
--- a/compiler/rustc_borrowck/src/nll.rs
+++ b/compiler/rustc_borrowck/src/nll.rs
@@ -1,9 +1,9 @@
 //! The entry point of the NLL borrow checker.
 
+use std::io;
 use std::path::PathBuf;
 use std::rc::Rc;
 use std::str::FromStr;
-use std::{env, io};
 
 use polonius_engine::{Algorithm, Output};
 use rustc_data_structures::fx::FxIndexMap;
@@ -21,6 +21,7 @@ use rustc_mir_dataflow::impls::MaybeInitializedPlaces;
 use rustc_mir_dataflow::move_paths::MoveData;
 use rustc_mir_dataflow::points::DenseLocationMap;
 use rustc_session::config::MirIncludeSpans;
+use rustc_span::Symbol;
 use rustc_span::symbol::sym;
 use tracing::{debug, instrument};
 
@@ -179,9 +180,11 @@ pub(crate) fn compute_regions<'a, 'tcx>(
         }
 
         if polonius_output {
-            let algorithm =
-                env::var("POLONIUS_ALGORITHM").unwrap_or_else(|_| String::from("Hybrid"));
-            let algorithm = Algorithm::from_str(&algorithm).unwrap();
+            let algorithm = infcx
+                .tcx
+                .env_var(Symbol::intern("POLONIUS_ALGORITHM"))
+                .unwrap_or_else(|| Symbol::intern("Hybrid"));
+            let algorithm = Algorithm::from_str(algorithm.as_str()).unwrap();
             debug!("compute_regions: using polonius algorithm {:?}", algorithm);
             let _prof_timer = infcx.tcx.prof.generic_activity("polonius_analysis");
             Some(Rc::new(Output::compute(all_facts, algorithm, false)))
diff --git a/compiler/rustc_lint/src/non_local_def.rs b/compiler/rustc_lint/src/non_local_def.rs
index 56f930ea7f62e..86375c1b93762 100644
--- a/compiler/rustc_lint/src/non_local_def.rs
+++ b/compiler/rustc_lint/src/non_local_def.rs
@@ -6,7 +6,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::{declare_lint, impl_lint_pass};
 use rustc_span::def_id::{DefId, LOCAL_CRATE};
 use rustc_span::symbol::kw;
-use rustc_span::{ExpnKind, MacroKind, Span, sym};
+use rustc_span::{ExpnKind, MacroKind, Span, Symbol, sym};
 
 use crate::lints::{NonLocalDefinitionsCargoUpdateNote, NonLocalDefinitionsDiag};
 use crate::{LateContext, LateLintPass, LintContext, fluent_generated as fluent};
@@ -105,8 +105,10 @@ impl<'tcx> LateLintPass<'tcx> for NonLocalDefinitions {
         // determining if we are in a doctest context can't currently be determined
         // by the code itself (there are no specific attributes), but fortunately rustdoc
         // sets a perma-unstable env var for libtest so we just reuse that for now
-        let is_at_toplevel_doctest =
-            || self.body_depth == 2 && std::env::var("UNSTABLE_RUSTDOC_TEST_PATH").is_ok();
+        let is_at_toplevel_doctest = || {
+            self.body_depth == 2
+                && cx.tcx.env_var(Symbol::intern("UNSTABLE_RUSTDOC_TEST_PATH")).is_some()
+        };
 
         match item.kind {
             ItemKind::Impl(impl_) => {