Two sequential returns at the same level trigger assertion "neighbors.len() <= 1"

[alfiedotwtf]

Related Component

compiler

Problem

I had some code, but needed to do some debugging so I added my debugging to the top of the function and then did a return. Something like this:

fn funcname() -> Option<u8> {
  // lots of debug logging
  ...

  return None;
 
  // lots of code
  ...

  // last line in function
  return None;
} 

Which caused the following error:

thread 'main' panicked at sway-core/src/control_flow_analysis/analyze_return_paths.rs:99:13:
assertion failed: neighbors.len() <= 1
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

I couldn't understand why my debugging was throwing that error and eventually I looked down and saw that last return and then commented it out. Presto it worked. I think assertion failed: neighbors.len() <= 1 may be doing some incorrect optimisation, because if you hide the first return in a branch, then it compiles without an error

Steps

Create the same code as above and try to compile.

Possible Solution(s)

No response

Notes

No response

Installed components

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