ci: test with bootstrap

Author: demosdemon

.github/workflows/ci.yml

@@ -43,17 +43,32 @@ jobs:
           - macos-latest
           - windows-latest
         rust:
-          - '1.86'
-          - '1.87'
-          - '1.88'
-          - '1.89'
-          - '1.90'
+          - "1.86"
+          - "1.87"
+          - "1.88"
+          - "1.89"
+          - "1.90"
           - stable
           - beta
           - nightly
+        rustc_bootstrap:
+          - "0"
+          - "1"
+        exclude:
+          # bootstrap is only relevant for non-nightly toolchains
+          - os: ubuntu-latest
+            rust: nightly
+            rustc_bootstrap: "0"
+          - os: macos-latest
+            rust: nightly
+            rustc_bootstrap: "0"
+          - os: windows-latest
+            rust: nightly
+            rustc_bootstrap: "0"
     runs-on: ${{ matrix.os }}
     env:
       RUSTFLAGS: "-D warnings"
+      RUSTC_BOOTSTRAP: ${{ matrix.rustc_bootstrap }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4