Error in alias analysis

[Lorentz Lasson]

When I run this (with latest source or 0.1 release)

app "repro"
    packages {
        # pf: "../basic-webserver/platform/main.roc",
        pf: "https://github.com/roc-lang/basic-webserver/releases/download/0.1/dCL3KsovvV-8A5D_W_0X_abynkcRcoAngsgF0xtvQsk.tar.br",
    }
    imports [
        pf.Task.{ Task },
        pf.Stdout,

        # Unused but needed to build
        pf.Http,
    ]

    provides [main] to pf

main = \_ ->
    when A is
        A ->
            {} <- Stdout.line "" |> Task.await
            respond

        _ ->
            respond

respond =
    Task.ok {
        status: 200,
        headers: [],
        body: [],
    }

I get this

$ RUST_BACKTRACE=full roc build repro.roc

── UNUSED IMPORT ─────────────────────────────────────────────────── repro.roc ─

Nothing from Http is used in this module.

11│          pf.Http,
             ^^^^^^^

Since Http isn't used, you don't need to import it.

────────────────────────────────────────────────────────────────────────────────

thread 'main' panicked at 'Error in alias analysis: error in module ModName("UserApp"), function definition FuncName("\x12\x00\x00\x00\x02\x00\x00\x00B\xf6\xc1\x05.\xbf\xec\xc7"), definition of value binding ValueId(3): could not find func in module ModName("UserApp") with name FuncName("%\x00\x00\x00\x04\x00\x00\x00B\xf6\xc1\x05.\xbf\xec\xc7")', crates/compiler/gen_llvm/src/llvm/build.rs:5743:19
stack backtrace:
   0:     0x555b894dded3 - <unknown>
   1:     0x555b8884717f - <unknown>
   2:     0x555b894d98a7 - <unknown>
   3:     0x555b894ddca5 - <unknown>
   4:     0x555b894df860 - <unknown>
   5:     0x555b894df624 - <unknown>
   6:     0x555b894dfd69 - <unknown>
   7:     0x555b894dfc74 - <unknown>
   8:     0x555b894de526 - <unknown>
   9:     0x555b894df9f2 - <unknown>
  10:     0x555b88746ea3 - <unknown>
  11:     0x555b88d7ee6c - <unknown>
  12:     0x555b88d78068 - <unknown>
  13:     0x555b88a43ccf - <unknown>
  14:     0x555b88a48319 - <unknown>
  15:     0x555b88a4705c - <unknown>
  16:     0x555b88b33d40 - <unknown>
  17:     0x555b88a15949 - <unknown>
  18:     0x555b88a094d3 - <unknown>
  19:     0x555b88a094f3 - <unknown>
  20:     0x555b894d0a45 - <unknown>
  21:     0x555b88a17d05 - <unknown>
  22:     0x7fb2b4229d90 - __libc_start_call_main
                               at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
  23:     0x7fb2b4229e40 - __libc_start_main_impl
                               at ./csu/../csu/libc-start.c:392:3
  24:     0x555b887dbe3e - <unknown>
  25:                0x0 - <unknown>

But if I remove the stdout line

@@ -16,7 +16,7 @@ app "repro"
 main = \_ ->
     when A is
         A ->
-            {} <- Stdout.line "" |> Task.await
+            # {} <- Stdout.line "" |> Task.await
             respond

         _ ->

or if I inline one of the task (which one doesn't matter)

@@ -20,7 +20,11 @@ main = \_ ->
             respond

         _ ->
-            respond
+            Task.ok {
+                status: 200,
+                headers: [],
+                body: [],
+            }

it compiles.

This is the minimal example I can come up with. Not sure if issues belongs here or for the compiler, but I haven't been able to repro with the basic-cli platform.

I am on ubuntu 22

[Anton-4]

Thanks for reporting @lorentzlasson!
This should be roc-lang/roc#5701 but we can leave this open to make sure this is also fixed when 5701 is fixed.