> ## Documentation Index
> Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Dart Rethrow Statement
The `rethrow` statement in Dart is a control flow keyword used exclusively within a `catch` block to propagate a caught exception up the call stack while preserving its original stack trace.
When an exception is caught, the Dart runtime captures both the exception object and the stack trace originating from the initial `throw` point. If an exception is re-raised using `throw e;` (where `e` is the caught exception), the runtime resets the stack trace to the location of that new `throw` statement. The `rethrow` keyword circumvents this reset, ensuring that the upstream error handler receives the exact execution context of the original failure.
```dart theme={"dark"}
try {
// Code that generates an exception
throw FormatException('Invalid input');
} catch (e, stackTrace) {
// Local inspection or side-effects occur here
rethrow; // Propagates the original exception and stackTrace
}
```
## Technical Characteristics
* **Lexical Scope Restriction:** The `rethrow` keyword is syntactically invalid and will result in a compile-time error if invoked outside the lexical scope of a `catch` clause.
* **Stack Trace Integrity:** It guarantees that the `StackTrace` object associated with the exception remains unmodified during propagation.
* **Unconditional Termination:** Execution of the current block terminates immediately at the `rethrow` statement. Control flow is unconditionally transferred to the nearest dynamically enclosing `try-catch` block.
* **Type Preservation:** The runtime type of the exception remains identical to the originally thrown object, allowing upstream `on` clauses to match the specific exception type accurately.
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