diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dbb01141..b8ca0490 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -156,8 +156,7 @@ jobs:
           - llvm: '15'
           - llvm: '16'
           - llvm: '17'
-          # TODO: LLVM 18 Installation broken: https://github.com/llvm/llvm-project/issues/99453
-          # - llvm: '18'
+          - llvm: '18'
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:
@@ -166,6 +165,7 @@ jobs:
         run: rustup update stable --no-self-update
       - name: Install LLVM
         run: |
+          set -eEuxo pipefail
           if type -P clang-"${{ matrix.llvm }}" &>/dev/null; then
             exit 0
           fi
@@ -193,27 +193,35 @@ jobs:
       - run: cargo install --path . --debug
       - name: Test
         run: |
+          set -eEuxo pipefail
           export CC="clang-${{ matrix.llvm }}"
           export CXX="clang++-${{ matrix.llvm }}"
           export LLVM_COV="llvm-cov-${{ matrix.llvm }}"
           export LLVM_PROFDATA="llvm-profdata-${{ matrix.llvm }}"
-          rustup toolchain add 1.60 1.65 1.70 1.73 1.77 --no-self-update
-          cargo clean
-          cargo +1.60 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          cargo clean
-          cargo +1.65 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          cargo clean
-          cargo +1.70 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          cargo clean
-          cargo +1.73 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          cargo clean
-          cargo +1.77 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          # TODO: LLVM 18 Installation broken: https://github.com/llvm/llvm-project/issues/99453
-          # rustup toolchain add 1.78 beta nightly --no-self-update
-          # cargo clean
-          # cargo +1.78 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          # cargo clean
-          # cargo +beta llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
-          # cargo clean
-          # cargo +nightly llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+          case "${{ matrix.llvm }}" in
+            1[0-7])
+              rustup toolchain add 1.60 1.65 1.70 1.73 1.77 --no-self-update
+              cargo clean
+              cargo +1.60 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +1.65 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +1.70 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +1.73 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +1.77 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              ;;
+            *)
+              rustup toolchain add 1.78 beta nightly --no-self-update
+              cargo clean
+              cargo +1.78 llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +stable llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +beta llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              cargo clean
+              cargo +nightly llvm-cov test --text --include-ffi --fail-under-lines 70 -vv
+              ;;
+          esac
         working-directory: tests/fixtures/crates/ffi