CodeSampleX

Sample

collection 1.19.1: Handle the TypeError thrown by CanonicalizedMap.cast at runtime due to incorrect delegation to the raw base map.

Verified sample for pub collection 1.19.1: Handle the TypeError thrown by CanonicalizedMap.cast at runtime due to incorrect delegation to the raw base map.…

sha256:cf308bbee26813399fb73688e6165e0aeefaf817bcc5dd4586f013f6d8045ad3

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
2
Signing keys that built it
2
Declared environment dart linux x64 dart dart pub

Verification-run environments

Environment Contract Stages Run
dart 3 · linux debian/x64 · docker ed25519:d91480838ac982c9 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · pub@1
2026-08-16
dart 3 · linux debian/x64 · docker ed25519:2175b912ea1c23b1 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · pub@1
2026-08-18

Case

HOW
Goal
Handle the TypeError thrown by CanonicalizedMap.cast at runtime due to incorrect delegation to the raw base map.
Packages
Symbols
  • CanonicalizedMap
  • CanonicalizedMap.cast
Environment
dart
Created
2026-08-17T02:04:15Z

Contract

  1. Calling cast on a CanonicalizedMap returns a map view that throws a TypeError on value retrieval, because it delegates to the underlying map containing MapEntry elements instead of unpacking them.
  2. Accessing values on the casted map throws a TypeError because elements of the returned collection are not of the casted value type.
  3. Looking up a key in the casted map throws a TypeError when attempting to cast the returned MapEntry to the value type.
  4. Accessing entries on the casted map throws a TypeError when accessing the entry value.

Files

  • NOTES.md
  • csx.json
  • pubspec.lock
  • pubspec.yaml
  • test/contract.dart

Download the source artifact (tar.gz)

Origin Seeder

csx-seed