UNIXServer does not create socket file when launches with -d option

[SlayerShadow]

When program launches on debug mode, unix socket file does not appear on file system.
The code as simple as possible:

require "socket"
s = UNIXServer.new "test.sock" # same for "/tmp/test.sock"
p File.exists?( "test.sock" ) # or "/tmp/test.sock"

crystal run server.cr -d returns false but the same ruby launching and crystal run server.cr returns true.

crystal -v:
Crystal 0.20.1 [18e7617] (2016-12-05)

uname -a:
Linux LocalName 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64 GNU/Linux

[asterite]

Compiling with -d --emit llvm-ir to the compiler gives this error:

Module validation failed: inlinable function call in a function with debug info must have a !dbg location
  %83 = call %"String::Builder"* @"*String::Builder::new<Int32>:String::Builder"(i32 119)
inlinable function call in a function with debug info must have a !dbg location
  %84 = call %"String::Builder"* @"*String::Builder@IO#<<<String>:String::Builder"(%"String::Builder"* %83, %String* bitcast ({ i32, i32, i32, [11 x i8] }* @"'cast from '" to %String*))
inlinable function call in a function with debug info must have a !dbg location
  %94 = call %"String::Builder"* @"*String::Builder@IO#<<<(PrettyPrint::Breakable:Class | PrettyPrint::Text:Class)>:String::Builder"(%"String::Builder"* %84, %"(PrettyPrint::Breakable:Class | PrettyPrint::Text:Class)" %93)
inlinable function call in a function with debug info must have a !dbg location
  %95 = call %"String::Builder"* @"*String::Builder@IO#<<<String>:String::Builder"(%"String::Builder"* %94, %String* bitcast ({ i32, i32, i32, [29 x i8] }* @"' to PrettyPrint::Te...'" to %String*))
inlinable function call in a function with debug info must have a !dbg location
  %96 = call %"String::Builder"* @"*String::Builder@IO#<<<String>:String::Builder"(%"String::Builder"* %95, %String* bitcast ({ i32, i32, i32, [67 x i8] }* @"', at /Users/asterit...'" to %String*))
inlinable function call in a function with debug info must have a !dbg location
  %97 = call %String* @"*String::Builder#to_s:String"(%"String::Builder"* %96)
inlinable function call in a function with debug info must have a !dbg location
  %98 = call %TypeCastError* @"*TypeCastError::new<String>:TypeCastError"(%String* %97)

It's strange that the error doesn't happen without passing --emit llvm-ir, seems the verification pass we are invoking doesn't do much regarding debug info...

[asterite]

Probably similar to #3584