diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 337cf3b0..5b545cf3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -169,20 +169,39 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: coverage-cargo-${{ hashFiles('**/Cargo.toml') }}
+      - name: install grcov
+        run: |
+          wget https://github.com/mozilla/grcov/releases/download/v${GRCOV_VERSION}/grcov-linux-x86_64.tar.bz2 -qO- | tar -xjvf -
+          mv grcov ~/.cargo/bin
+        env:
+          GRCOV_VERSION: 0.7.1
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: nightly
           override: true
           profile: minimal
-      - run: cargo test --no-default-features --no-fail-fast
-      - run: cargo test --no-default-features --no-fail-fast --features "macros num-bigint num-complex hashbrown serde multiple-pymethods"
-      - uses: actions-rs/grcov@v0.1
-        id: coverage
+          components: llvm-tools-preview
+      - run: LLVM_PROFILE_FILE="coverage-%p-%m.profraw" cargo test --no-default-features --no-fail-fast
+      - run: LLVM_PROFILE_FILE="coverage-features-%p-%m.profraw" cargo test --no-default-features --no-fail-fast --features "macros num-bigint num-complex hashbrown serde multiple-pymethods"
+      # can't yet use actions-rs/grcov with source-based coverage: https://github.com/actions-rs/grcov/issues/105
+      # - uses: actions-rs/grcov@v0.1
+      #   id: coverage
+      # - uses: codecov/codecov-action@v1
+      #   with:
+      #     file: ${{ steps.coverage.outputs.report }}
+      - run: grcov . --binary-path target/debug/deps/ -s . -t lcov --branch --ignore-not-existing -o coverage.lcov
       - uses: codecov/codecov-action@v1
         with:
-          file: ${{ steps.coverage.outputs.report }}
+          file: coverage.lcov
+
     env:
       CARGO_TERM_VERBOSE: true
-      CARGO_INCREMENTAL: 0
-      RUSTFLAGS: "-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests"
-      RUSTDOCFLAGS: "-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests"
+      RUSTFLAGS: "-Zinstrument-coverage"
+      RUSTDOCFLAGS: "-Zinstrument-coverage"
diff --git a/src/err/mod.rs b/src/err/mod.rs
index 02d2dcf6..367f9064 100644
--- a/src/err/mod.rs
+++ b/src/err/mod.rs
@@ -557,12 +557,6 @@ mod tests {
     #[test]
     #[should_panic(expected = "new panic")]
     fn fetching_panic_exception_resumes_unwind() {
-        // TODO replace with #[cfg(panic = "unwind")] once stable
-        if !crate::cfg_panic_unwind() {
-            // panic to meet the expected abort in panic=abort :-/
-            panic!("new panic");
-        }
-
         use crate::panic::PanicException;
 
         let gil = Python::acquire_gil();
diff --git a/src/lib.rs b/src/lib.rs
index 4764011b..2350885d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -425,9 +425,3 @@ pub mod doc_test {
     doctest!("guide/src/trait_bounds.md", guide_trait_bounds_md);
     doctest!("guide/src/types.md", guide_types_md);
 }
-
-// interim helper until #[cfg(panic = ...)] is stable
-#[cfg(test)]
-fn cfg_panic_unwind() -> bool {
-    option_env!("RUSTFLAGS").map_or(true, |var| !var.contains("-Cpanic=abort"))
-}
diff --git a/src/python.rs b/src/python.rs
index 08d40862..8e8d2b3c 100644
--- a/src/python.rs
+++ b/src/python.rs
@@ -695,11 +695,6 @@ mod test {
 
     #[test]
     fn test_allow_threads_panics_safely() {
-        // TODO replace with #[cfg(panic = "unwind")] once stable
-        if !crate::cfg_panic_unwind() {
-            return;
-        }
-
         let gil = Python::acquire_gil();
         let py = gil.python();