File not found exception when loading assembly from function with double underscore

[paulbatum]

Repro steps

1. Create a C# function with two consecutive underscores in the name such as HttpTriggerCSharp__3.
2. Modify the function to load an assembly using #r such as #r "../bin/MyLibrary.dll"
3. Upload given library to the function app so that it should work

Expected behavior

Library is loaded

Actual

[Error] Exception while executing function: Functions.HttpTriggerCSharp__3. mscorlib: Exception has been thrown by the target of an invocation. f-HttpTriggerCSharp__3__576737419: Could not load file or assembly

Workaround

Avoid using function names with double underscores

Notes

This bug does not exist in functions V2.

[fabiocav]

This is relatively low priority, but an easy fix (an update to the regex used to extract the function information to load its context)