## IL ret not allowed in a try region

### Scope
Edge

### Version Introduced
4.6

### Source Analyzer Status
Planned

### Change Description
Unlike the JIT64 just-in-time compiler, RyuJIT (used in .NET 4.6) does not allow an IL ret instruction in a try region. Returning from a try region is disallowed by the ECMA-335 specification, and no known managed compiler generates such IL. However, the JIT64 compiler will execute such IL if it is generated using reflection emit.

- [x] Quirked
- [ ] Build-time break

### Recommended Action
If an app is generating IL that includes a ret opcode in a try region, the app may target .NET 4.5 to use the old JIT and avoid this break. Alternatively, the generated IL may be updated to return after the try region.

### Affected APIs
* Not detectable via API analysis

### Category
JIT

[More information](https://msdn.microsoft.com/en-us/library/dn833125(v=vs.110).aspx#RyuJIT)

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    ### Notes
    We could maybe detect this by looking for apps that emit ret opcodes, but we'd have to also know whether they were emitted into a try block.
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