EC
TS2517
TypeScriptERRORNotableTypeHIGH confidence

Cannot assign an abstract constructor type to a non-abstract constructor type.

Production Risk

Build will fail; resolve before shipping.

What this means

A type-checking error (TS2517): Cannot assign an abstract constructor type to a non-abstract constructor type.. This diagnostic is emitted by the TypeScript compiler when cannot assign an abstract constructor type to a non-abstract constructor type..

Why it happens
  1. 1A concrete class extends an abstract class but does not implement all abstract members
How to reproduce

TypeScript compiler reports TS2517 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS2517
// Cannot assign an abstract constructor type to a non-abstract constructor type.

expected output

error TS2517: Cannot assign an abstract constructor type to a non-abstract constructor type.

Fix

Implement all abstract members

WHEN Extending an abstract class

Implement all abstract members
abstract class Base {
  abstract doWork(): void;
}
class Derived extends Base {
  doWork(): void { /* implementation */ }
}

Why this works

All abstract members must be implemented in concrete subclasses.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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