Enforce that abstract members are implemented

This adds a check that abstract members must be implemented.
If any members lack an implementation, an error is thrown describing
the missing members.

Also: we have a bug in `pkl:base`; class `Set` does not implement all
members of class `Collection`.

.github/workflows/__lockfile__.yml

@@ -19,7 +19,7 @@ jobs:
     - name: EnricoMi/publish-unit-test-result-action@v2
       uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
     - name: actions/checkout@v6
-      uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+      uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
     - name: actions/create-github-app-token@v2
       uses: actions/create-github-app-token@fee1f7d63c2ff003460e3d139729b119787bc349 # v2
     - name: actions/download-artifact@v6
@@ -31,9 +31,9 @@ jobs:
     - name: dawidd6/action-download-artifact@v11
       uses: dawidd6/action-download-artifact@ac66b43f0e6a346234dd65d4d0c8fbb31cb316e5 # v11
     - name: github/codeql-action/analyze@v4
-      uses: github/codeql-action/analyze@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+      uses: github/codeql-action/analyze@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
     - name: github/codeql-action/init@v4
-      uses: github/codeql-action/init@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+      uses: github/codeql-action/init@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
     - name: gradle/actions/dependency-submission@v6
       uses: gradle/actions/dependency-submission@50e97c2cd7a37755bbfafc9c5b7cafaece252f6e # v6
     - name: gradle/actions/setup-gradle@v5

.github/workflows/build.yml

@@ -19,7 +19,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -60,7 +60,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -100,7 +100,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -126,7 +126,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -166,7 +166,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -185,7 +185,7 @@ jobs:
         if [[ "$RUNNER_DEBUG" -eq 1 ]]; then
           echo "DEBUG_ARGS=--info --stacktrace" >> $GITHUB_ENV
         fi
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - name: gradle build java executables
@@ -217,7 +217,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -263,7 +263,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -314,7 +314,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -360,7 +360,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -408,7 +408,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -526,7 +526,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -573,7 +573,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -619,7 +619,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -670,7 +670,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -716,7 +716,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -764,7 +764,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -882,7 +882,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5

.github/workflows/codeql.yml

@@ -15,15 +15,15 @@ jobs:
       security-events: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
-    - uses: github/codeql-action/init@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+    - uses: github/codeql-action/init@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
       with:
         languages: actions
         build-mode: none
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+      uses: github/codeql-action/analyze@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
       with:
         category: /language:actions
   analyze-java-kotlin:
@@ -32,15 +32,15 @@ jobs:
       security-events: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
-    - uses: github/codeql-action/init@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+    - uses: github/codeql-action/init@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
       with:
         languages: java-kotlin
         build-mode: autobuild
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+      uses: github/codeql-action/analyze@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
       with:
         category: /language:java-kotlin
   analyze-javascript-typescript:
@@ -49,14 +49,14 @@ jobs:
       security-events: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
-    - uses: github/codeql-action/init@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+    - uses: github/codeql-action/init@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
       with:
         languages: javascript-typescript
         build-mode: none
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@7211b7c8077ea37d8641b6271f6a365a22a5fbfa # v4
+      uses: github/codeql-action/analyze@8aad20d150bbac5944a9f9d289da16a4b0d87c1e # v4
       with:
         category: /language:javascript-typescript

.github/workflows/main.yml

@@ -17,7 +17,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -58,7 +58,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -98,7 +98,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -124,7 +124,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -164,7 +164,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -183,7 +183,7 @@ jobs:
         if [[ "$RUNNER_DEBUG" -eq 1 ]]; then
           echo "DEBUG_ARGS=--info --stacktrace" >> $GITHUB_ENV
         fi
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - name: gradle build java executables
@@ -215,7 +215,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -261,7 +261,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -312,7 +312,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -358,7 +358,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -406,7 +406,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -524,7 +524,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -571,7 +571,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -617,7 +617,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -668,7 +668,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -714,7 +714,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -762,7 +762,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -880,7 +880,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -943,7 +943,7 @@ jobs:
       LANG: en_US.UTF-8
     environment: maven-release
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -961,7 +961,7 @@ jobs:
         if [[ "$RUNNER_DEBUG" -eq 1 ]]; then
           echo "DEBUG_ARGS=--info --stacktrace" >> $GITHUB_ENV
         fi
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6
@@ -980,7 +980,7 @@ jobs:
       contents: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5

.github/workflows/prb.yml

@@ -13,7 +13,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -56,7 +56,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -100,7 +100,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -148,7 +148,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -200,7 +200,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -248,7 +248,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -298,7 +298,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -418,7 +418,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -466,7 +466,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -514,7 +514,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -566,7 +566,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -614,7 +614,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -664,7 +664,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -784,7 +784,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -861,7 +861,7 @@ jobs:
   check-pkl-github-actions:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - name: Setup Pkl

.github/workflows/release-branch.yml

@@ -17,7 +17,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -58,7 +58,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -98,7 +98,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -124,7 +124,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -164,7 +164,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -183,7 +183,7 @@ jobs:
         if [[ "$RUNNER_DEBUG" -eq 1 ]]; then
           echo "DEBUG_ARGS=--info --stacktrace" >> $GITHUB_ENV
         fi
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - name: gradle build java executables
@@ -215,7 +215,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -261,7 +261,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -312,7 +312,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -358,7 +358,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -406,7 +406,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -524,7 +524,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -571,7 +571,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -617,7 +617,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -668,7 +668,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -714,7 +714,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -762,7 +762,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -880,7 +880,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5

.github/workflows/release.yml

@@ -17,7 +17,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -58,7 +58,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -98,7 +98,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -124,7 +124,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -164,7 +164,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
         fetch-depth: 0
@@ -184,7 +184,7 @@ jobs:
         if [[ "$RUNNER_DEBUG" -eq 1 ]]; then
           echo "DEBUG_ARGS=--info --stacktrace" >> $GITHUB_ENV
         fi
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - name: gradle build java executables
@@ -216,7 +216,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -263,7 +263,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -315,7 +315,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -362,7 +362,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -411,7 +411,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -530,7 +530,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -578,7 +578,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -625,7 +625,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -677,7 +677,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -724,7 +724,7 @@ jobs:
     steps:
     - name: Install deps
       run: dnf install -y git binutils gcc glibc-devel zlib-devel libstdc++-static glibc-langpack-en
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -773,7 +773,7 @@ jobs:
     env:
       LANG: en_US.UTF-8
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -892,7 +892,7 @@ jobs:
       LANG: en_US.UTF-8
       JAVA_HOME: /jdk
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -956,7 +956,7 @@ jobs:
       LANG: en_US.UTF-8
     environment: maven-release
     steps:
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5
@@ -975,7 +975,7 @@ jobs:
         if [[ "$RUNNER_DEBUG" -eq 1 ]]; then
           echo "DEBUG_ARGS=--info --stacktrace" >> $GITHUB_ENV
         fi
-    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       with:
         persist-credentials: false
     - uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6

gradle/libs.versions.toml

@@ -29,7 +29,7 @@ graalVmSha256-windows-x64 = "fde83c5ceec2c75560c747ccd9f314f90e4cf5c5287416e67c4
 #noinspection UnusedVersionCatalogEntry
 graalVmSha256-windows-aarch64 = "unavailable"
 ideaExtPlugin = "1.4.1"
-javaPoet = "0.15.0"
+javaPoet = "0.16.0"
 javaxInject = "1"
 jimfs = "1.3.1"
 jline = "4.1.3"
@@ -56,7 +56,7 @@ msgpack = "0.9.12"
 nexusPublishPlugin = "2.0.0"
 nullaway = "0.13.4"
 nullawayPlugin = "3.0.0"
-nuValidator = "26.5.22"
+nuValidator = "26.5.29"
 paguro = "3.10.3"
 shadowPlugin = "9.4.2"
 slf4j = "2.0.18"

pkl-core/src/main/java/org/pkl/core/ast/member/ClassProperty.java

@@ -24,7 +24,7 @@ import org.pkl.core.ast.VmModifier;
 import org.pkl.core.runtime.*;
 
 public final class ClassProperty extends ClassMember {
-  private final @Nullable PropertyTypeNode typeNode;
+  private @Nullable PropertyTypeNode typeNode;
   private final ObjectMember initializer;
 
   public ClassProperty(
@@ -64,6 +64,11 @@ public final class ClassProperty extends ClassMember {
     return VmModifier.getMirrors(mods, false);
   }
 
+  public void lateInitTypeNodeAndModifiers(@Nullable PropertyTypeNode typeNode, int modifiers) {
+    this.typeNode = typeNode;
+    this.modifiers = modifiers;
+  }
+
   public @Nullable PropertyTypeNode getTypeNode() {
     return typeNode;
   }

pkl-core/src/main/java/org/pkl/core/ast/member/Member.java

@@ -25,7 +25,7 @@ public abstract class Member {
 
   protected final SourceSection headerSection;
 
-  protected final int modifiers;
+  protected int modifiers;
 
   protected final @Nullable Identifier name;
 

pkl-core/src/main/java/org/pkl/core/runtime/VmClass.java

@@ -22,6 +22,7 @@ import com.oracle.truffle.api.dsl.Idempotent;
 import com.oracle.truffle.api.frame.FrameDescriptor;
 import com.oracle.truffle.api.source.SourceSection;
 import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.*;
 import org.graalvm.collections.*;
 import org.jspecify.annotations.Nullable;
@@ -84,6 +85,13 @@ public final class VmClass extends VmValue {
 
   private final Object allHiddenPropertyNamesLock = new Object();
 
+  @GuardedBy("finalizersLock")
+  private @Nullable List<Runnable> __finalizers = null;
+
+  private final Object finalizersLock = new Object();
+
+  private final AtomicInteger uninitializedSuperclassCount = new AtomicInteger(0);
+
   // Helps to overcome recursive initialization issues
   // between classes and annotations in pkl.base.
   @CompilationFinal private volatile boolean isInitialized;
@@ -150,6 +158,83 @@ public final class VmClass extends VmValue {
     prototype.lateInitParent(superclass.getPrototype());
   }
 
+  @TruffleBoundary
+  private void checkAbstractMembers() {
+    if (this.isAbstract()) return;
+    // minimize allocations in the non-error case
+    if (!hasAbstractMember()) return;
+    var abstractMembers = getAbstractMembers();
+    if (abstractMembers.size() == 1) {
+      var member = abstractMembers.get(0);
+      var message =
+          member instanceof ClassProperty
+              ? "noImplementationForAbstractProperty"
+              : "noImplementationForAbstractMethod";
+      throw new VmExceptionBuilder()
+          .evalError(message, getDisplayName(), member.getName().toString())
+          .withSourceSection(getHeaderSection())
+          .build();
+    }
+    var memberList = new StringBuilder();
+    var isFirst = true;
+    for (var member : abstractMembers) {
+      if (isFirst) {
+        isFirst = false;
+      } else {
+        memberList.append('\n');
+      }
+      memberList.append("* ");
+      if (member instanceof ClassProperty) {
+        memberList.append("property ");
+      } else {
+        memberList.append("method ");
+      }
+      memberList.append('`').append(member.getName()).append('`');
+    }
+    throw new VmExceptionBuilder()
+        .evalError("noImplementationForAbstractMembers", getDisplayName(), memberList.toString())
+        .withSourceSection(getHeaderSection())
+        .build();
+  }
+
+  private boolean hasAbstractMember() {
+    var propertyCursor = getAllProperties().getEntries();
+    while (propertyCursor.advance()) {
+      var property = propertyCursor.getValue();
+      if (property.isAbstract()) {
+        return true;
+      }
+    }
+    var methodCursor = getAllMethods().getEntries();
+    while (methodCursor.advance()) {
+      var method = methodCursor.getValue();
+      if (method.isAbstract()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private List<ClassMember> getAbstractMembers() {
+    assert this.superclass != null;
+    var result = new ArrayList<ClassMember>();
+    var propertyCursor = getAllProperties().getEntries();
+    while (propertyCursor.advance()) {
+      var property = propertyCursor.getValue();
+      if (property.isAbstract()) {
+        result.add(property);
+      }
+    }
+    var methodCursor = getAllMethods().getEntries();
+    while (methodCursor.advance()) {
+      var method = methodCursor.getValue();
+      if (method.isAbstract()) {
+        result.add(method);
+      }
+    }
+    return result;
+  }
+
   @TruffleBoundary
   public void addProperty(ClassProperty property) {
     prototype.addProperty(property.getInitializer());
@@ -190,8 +275,46 @@ public final class VmClass extends VmValue {
     }
   }
 
+  private void onInitialized(Runnable runnable) {
+    synchronized (finalizersLock) {
+      if (this.__finalizers == null) {
+        this.__finalizers = new ArrayList<>();
+      }
+      this.__finalizers.add(runnable);
+    }
+  }
+
   // Note: Superclasses may not have finished their initialization when this method is called.
   public void notifyInitialized() {
+    var sc = superclass;
+    var isAllInitialized = true;
+    var uninitializedCount = 0;
+    while (sc != null) {
+      if (!sc.isInitialized) {
+        sc.onInitialized(
+            () -> {
+              var count = uninitializedSuperclassCount.decrementAndGet();
+              if (count == 0) {
+                checkAbstractMembers();
+              }
+            });
+        uninitializedCount++;
+        isAllInitialized = false;
+      }
+      sc = sc.superclass;
+    }
+    uninitializedSuperclassCount.set(uninitializedCount);
+    if (isAllInitialized) {
+      checkAbstractMembers();
+    }
+    lock:
+    synchronized (finalizersLock) {
+      if (__finalizers == null) break lock;
+      for (var finalizer : __finalizers) {
+        finalizer.run();
+      }
+      this.__finalizers = null;
+    }
     isInitialized = true;
   }
 
@@ -735,13 +858,27 @@ public final class VmClass extends VmValue {
     for (var property : EconomicMaps.getValues(declaredProperties)) {
       if (property.isLocal()) continue;
 
-      // A property is considered a class property definition
+      // A property is considered a class property definition if any of the following are true:
-      // if it has a type annotation or has no superdefinition (ad-hoc case).
+      //
+      // 1. It has a type annotation.
+      // 2. It has no superdefinition.
+      // 3. It is not abstract but its superclass is.
+      //
       // Otherwise, it is considered an object property definition,
       // which means it affects the class prototype but not the class itself.
       // An example for the latter is when `Module.output` is overridden with `output { ... }`.
-      if (property.getTypeNode() != null || !EconomicMaps.containsKey(result, property.getName())) {
+      if (property.getTypeNode() != null) {
         EconomicMaps.put(result, property.getName(), property);
+      } else {
+        var existingProperty = EconomicMaps.get(result, property.getName());
+        if (existingProperty != null && existingProperty.isAbstract() && !this.isAbstract()) {
+          property.lateInitTypeNodeAndModifiers(
+              existingProperty.getTypeNode(),
+              existingProperty.getModifiers() & ~VmModifier.ABSTRACT);
+          EconomicMaps.put(result, property.getName(), property);
+        } else if (existingProperty == null) {
+          EconomicMaps.put(result, property.getName(), property);
+        }
       }
     }
 

pkl-core/src/main/resources/org/pkl/core/errorMessages.properties

@@ -1176,3 +1176,13 @@ Cannot follow redirect from ''https:'' URL to ''http:'' URL.\
 \n\
 HTTP Request: `GET {0}`\n\
 Redirected to: `{1}`
+
+noImplementationForAbstractProperty=\
+Class `{0}` should either be declared `abstract`, or should implement property `{1}`.
+
+noImplementationForAbstractMethod=\
+Class `{0}` should either be declared `abstract`, or should implement method `{1}`.
+
+noImplementationForAbstractMembers=\
+Class `{0}` should either be declared `abstract`, or implement the following members:\n\
+{1}

pkl-core/src/test/files/LanguageSnippetTests/input-helper/classes/AbstractModule.pkl

@@ -0,0 +1,3 @@
+abstract module Foo
+
+abstract bar: Int

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented1.pkl

@@ -0,0 +1,19 @@
+abstract class AbstractProperty {
+  abstract foo: Int
+}
+
+abstract class AbstractMethod {
+  abstract function foo(): Int
+}
+
+abstract class AbstractPropertiesAndMethods {
+  abstract foo: Int
+  abstract bar: Int
+  abstract function foo(): Int
+  abstract function bar(): Int
+}
+
+class MyClass extends AbstractProperty {
+}
+
+foo: MyClass

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented2.pkl

@@ -0,0 +1,9 @@
+abstract class AbstractMethod {
+  abstract function foo(): Int
+}
+
+class MyClass extends AbstractMethod {
+}
+
+foo: MyClass
+

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented3.pkl

@@ -0,0 +1,10 @@
+abstract class AbstractPropertiesAndMethods {
+  abstract foo: Int
+  abstract bar: Int
+  abstract function foo(): Int
+  abstract function bar(): Int
+}
+
+class MyClass extends AbstractPropertiesAndMethods {}
+
+foo: MyClass

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented4.pkl

@@ -0,0 +1 @@
+extends "../../input-helper/classes/AbstractModule.pkl"

pkl-core/src/test/files/LanguageSnippetTests/output/api/reflectedDeclaration.pcf

@@ -889,7 +889,7 @@ alias {
             ```
             !"".isNotBlank
             !"   ".isNotBlank
-            "\\t\\n\\r".isNotBlank
+            !"\\t\\n\\r".isNotBlank
             "abc".isNotBlank
             ```
             """
@@ -1254,7 +1254,7 @@ alias {
             ```
             !"".isNotBlank
             !"   ".isNotBlank
-            "\\t\\n\\r".isNotBlank
+            !"\\t\\n\\r".isNotBlank
             "abc".isNotBlank
             ```
             """

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented1.err

@@ -0,0 +1,10 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented1#MyClass` should either be declared `abstract`, or should implement property `foo`.
+
+xx | class MyClass extends AbstractProperty {
+     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented1#MyClass (file:///$snippetsDir/input/errors/abstractMemberNotImplemented1.pkl)
+
+xx | foo: MyClass
+          ^^^^^^^
+at abstractMemberNotImplemented1 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented1.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented2.err

@@ -0,0 +1,10 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented2#MyClass` should either be declared `abstract`, or should implement method `foo`.
+
+x | class MyClass extends AbstractMethod {
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented2#MyClass (file:///$snippetsDir/input/errors/abstractMemberNotImplemented2.pkl)
+
+x | foo: MyClass
+         ^^^^^^^
+at abstractMemberNotImplemented2 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented2.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented3.err

@@ -0,0 +1,14 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented3#MyClass` should either be declared `abstract`, or implement the following members:
+* property `foo`
+* property `bar`
+* method `foo`
+* method `bar`
+
+x | class MyClass extends AbstractPropertiesAndMethods {}
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented3#MyClass (file:///$snippetsDir/input/errors/abstractMemberNotImplemented3.pkl)
+
+xx | foo: MyClass
+          ^^^^^^^
+at abstractMemberNotImplemented3 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented3.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented4.err

@@ -0,0 +1,6 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented4` should either be declared `abstract`, or should implement property `bar`.
+
+x | extends "../../input-helper/classes/AbstractModule.pkl"
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented4 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented4.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMethodsNotImplemented.err

@@ -0,0 +1,10 @@
+–– Pkl Error ––
+Class `abstractMethodsNotImplemented#MyClass` either needs to be abstract, or should implement property `foo`.
+
+x | class MyClass extends MyAbstractClass {
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMethodsNotImplemented#MyClass (file:///$snippetsDir/input/errors/abstractMethodsNotImplemented.pkl)
+
+x | foo: MyClass
+         ^^^^^^^
+at abstractMethodsNotImplemented (file:///$snippetsDir/input/errors/abstractMethodsNotImplemented.pkl)

stdlib/base.pkl

@@ -1314,7 +1314,7 @@ external class String extends Any {
   /// ```
   /// !"".isNotBlank
   /// !"   ".isNotBlank
-  /// "\t\n\r".isNotBlank
+  /// !"\t\n\r".isNotBlank
   /// "abc".isNotBlank
   /// ```
   @Since { version = "0.31.0" }
@@ -1904,7 +1904,6 @@ external class DataSize extends Any {
   /// Facts:
   /// ```
   /// 1024.kb.toBinaryUnit() == 1000.kib
-  /// 1024.mb.toBinaryUnit() == 1000.mib
   ///
   /// 1000.kib.toBinaryUnit() == 1000.kib
   /// 1000.b.toBinaryUnit() == 1000.b
@@ -1918,7 +1917,6 @@ external class DataSize extends Any {
   /// Facts:
   /// ```
   /// 1000.kib.toDecimalUnit() == 1024.kb
-  /// 1000.mib.toDecimalUnit() == 1024.mb
   ///
   /// 1000.kb.toDecimalUnit() == 1000.kb
   /// 1000.b.toDecimalUnit() == 1000.b
@@ -2673,7 +2671,7 @@ abstract external class Collection<out Element> extends Any {
   /// Facts:
   /// ```
   /// List(1, 2, 3).any((n) -> n.isEven)
-  /// !List(1, 2, 3).any((n) -> n.isEven)
+  /// !List(1, 3, 5).any((n) -> n.isEven)
   /// !List().any((n) -> n.isEven)
   /// ```
   @AlsoKnownAs { names { "exists" } }
@@ -3066,7 +3064,7 @@ external class IntSeq extends Any {
   ///
   /// Facts:
   /// ```
-  /// IntSeq(2, 5).start == 5
+  /// IntSeq(2, 5).end == 5
   /// ```
   external end: Int
 
@@ -3249,7 +3247,7 @@ external class List<out Element> extends Collection<Element> {
   ///
   /// Facts:
   /// ```
-  /// List("a", "b", "abc").isDistinctBy((it) -> it.length)
+  /// List("a", "bb", "ccc").isDistinctBy((it) -> it.length)
   /// !List("a", "ab", "c").isDistinctBy((it) -> it.length)
   /// ```
   @AlsoKnownAs { names { "isUniqueBy" } }
@@ -3272,7 +3270,7 @@ external class List<out Element> extends Collection<Element> {
   ///
   /// Facts:
   /// ```
-  /// List("a", "b", "abc").distinctBy((it) -> it.length) == List("a", "b", "abc")
+  /// List("a", "bb", "ccc").distinctBy((it) -> it.length) == List("a", "bb", "ccc")
   /// List("a", "ab", "c").distinctBy((it) -> it.length) == List("a", "ab")
   /// ```
   @AlsoKnownAs { names { "uniqueBy" } }
@@ -3564,6 +3562,18 @@ external class Set<out Element> extends Collection<Element> {
 
   /// The difference of this set and [other].
   external function difference(other: Set): Set<Element>
+
+  function indexOf(_): Int = throw("Set does not implement `indexOf`")
+  function indexOfOrNull(_): Int? = throw("Set does not implement `indexOfOrNull`")
+
+  function lastIndexOf(_): Int = throw("Set does not implement `lastIndexOf`")
+  function lastIndexOfOrNull(_): Int? = throw("Set does not implement `lastIndexOfOrNull`")
+
+  function findIndex(_): Int = throw("Set does not implement `findIndex`")
+  function findIndexOrNull(_): Int? = throw("Set does not implement `findIndexOrNull`")
+
+  function findLastIndex(_): Int = throw("Set does not implement `findLastIndex`")
+  function findLastIndexOrNull(_): Int? = throw("Set does not implement `findLastIndexOrNull`")
 }
 
 /// Creates a map containing the given alternating [keysAndValues].
@@ -3573,7 +3583,7 @@ external class Set<out Element> extends Collection<Element> {
 /// ```
 /// Map().isEmpty
 /// Map("name", "Pigeon", "age", 42).keys == Set("name", "age")
-/// Map("name", "Pigeon", "age", 42).values == Set("Pigeon", 42)
+/// Map("name", "Pigeon", "age", 42).values == List("Pigeon", 42)
 /// ```
 external const function Map<Key, Value>(keysAndValues: VarArgs<Key | Value>): Map<Key, Value>