diff --git a/crates/cargo-test-support/src/lib.rs b/crates/cargo-test-support/src/lib.rs
index 64efa03a9..04d6ce9f8 100644
--- a/crates/cargo-test-support/src/lib.rs
+++ b/crates/cargo-test-support/src/lib.rs
@@ -1234,28 +1234,34 @@ pub trait TestEnv: Sized {
             .env("__CARGO_TEST_CHANNEL_OVERRIDE_DO_NOT_USE_THIS", "stable")
             // Keeps cargo within its sandbox.
             .env("__CARGO_TEST_DISABLE_GLOBAL_KNOWN_HOST", "1")
-            // For now disable incremental by default as support hasn't ridden to the
-            // stable channel yet. Once incremental support hits the stable compiler we
-            // can switch this to one and then fix the tests.
+            // Incremental generates a huge amount of data per test, which we
+            // don't particularly need. Tests that specifically need to check
+            // the incremental behavior should turn this back on.
             .env("CARGO_INCREMENTAL", "0")
+            // Don't read the system git config which is out of our control.
+            .env("GIT_CONFIG_NOSYSTEM", "1")
             .env_remove("__CARGO_DEFAULT_LIB_METADATA")
-            .env_remove("RUSTC")
-            .env_remove("RUSTDOC")
-            .env_remove("RUSTC_WRAPPER")
-            .env_remove("RUSTFLAGS")
-            .env_remove("RUSTDOCFLAGS")
-            .env_remove("XDG_CONFIG_HOME") // see #2345
-            .env("GIT_CONFIG_NOSYSTEM", "1") // keep trying to sandbox ourselves
+            .env_remove("ALL_PROXY")
             .env_remove("EMAIL")
-            .env_remove("USER") // not set on some rust-lang docker images
-            .env_remove("MFLAGS")
-            .env_remove("MAKEFLAGS")
-            .env_remove("GIT_AUTHOR_NAME")
             .env_remove("GIT_AUTHOR_EMAIL")
-            .env_remove("GIT_COMMITTER_NAME")
+            .env_remove("GIT_AUTHOR_NAME")
             .env_remove("GIT_COMMITTER_EMAIL")
+            .env_remove("GIT_COMMITTER_NAME")
+            .env_remove("http_proxy")
+            .env_remove("HTTPS_PROXY")
+            .env_remove("https_proxy")
+            .env_remove("MAKEFLAGS")
+            .env_remove("MFLAGS")
+            .env_remove("MSYSTEM") // assume cmd.exe everywhere on windows
+            .env_remove("RUSTC")
+            .env_remove("RUSTC_WORKSPACE_WRAPPER")
+            .env_remove("RUSTC_WRAPPER")
+            .env_remove("RUSTDOC")
+            .env_remove("RUSTDOCFLAGS")
+            .env_remove("RUSTFLAGS")
             .env_remove("SSH_AUTH_SOCK") // ensure an outer agent is never contacted
-            .env_remove("MSYSTEM"); // assume cmd.exe everywhere on windows
+            .env_remove("USER") // not set on some rust-lang docker images
+            .env_remove("XDG_CONFIG_HOME"); // see #2345
         if cfg!(target_os = "macos") {
             // Work-around a bug in macOS 10.15, see `link_or_copy` for details.
             self = self.env("__CARGO_COPY_DONT_LINK_DO_NOT_USE_THIS", "1");