Find All References sometimes doesn't work on a let binding in implementation file

[0101]

Repro steps

1. In FSharp.Compiler.Service project go to Utilities/range.fs
2. Find module Position
3. Do "Find All References" on mkPos

Expected behavior

• References are found

Actual behavior

• Nothing is found

• However, if you do the same on mkPos' signature or one of the call sites, they are found

Known workarounds

Go to signature and find references from there.

Related information

• Same thing happens with e.g. Position.pos0 or Range.mkFileIndexRange.

• But e.g. Position.posGt and Range.mkRange work fine.