@errorCast(...) with inferred error set hits assertion during semantic analysis

[tauoverpi]

Zig Version

0.14.0-dev.2643+fb43e91b2

Steps to Reproduce and Observed Behavior

found by Narctis on matrix, the following:

pub fn main() !void {
    return @errorCast(error.Foo);
}

results in tripping an assertion:

$ zig build-exe -fno-emit-bin bar.zig
thread 30939 panic: reached unreachable code
Analyzing bar.zig
      %2 = ret_type() 
      %3 = dbg_stmt(2, 12)
      %4 = error_value("Foo") 
    > %5 = extended(error_cast(%2, %4)) 
      %6 = dbg_stmt(2, 5)
      %7 = restore_err_ret_index_fn_entry(%5) 
      %8 = ret_node(%5) 
    For full context, use the command
      zig ast-check -t bar.zig

  in /home/tau/tmp/zig/zig-out/lib/zig/std/start.zig
    > %2052 = is_non_err(%2051) 
  in /home/tau/tmp/zig/zig-out/lib/zig/std/start.zig
    > %2054 = block({%2049..%2053}) 
  in /home/tau/tmp/zig/zig-out/lib/zig/std/start.zig
    > %2016 = switch_block(%2011,
        else => {%2034..%2138},
        @void_type => {%2017..%2025},
        @noreturn_type, @u8_type => {%2026..%2033}) 
  in /home/tau/tmp/zig/zig-out/lib/zig/std/start.zig
    > %1812 = call(.auto, %1810, []) 
  in /home/tau/tmp/zig/zig-out/lib/zig/std/start.zig
    > %1633 = call(.auto, %1631, [
        {%1634},
        {%1635},
        {%1636},
      ]) 
  in /home/tau/tmp/zig/zig-out/lib/zig/std/start.zig
    > %1630 = field_call(nodiscard .auto, %1628, "exit", [
        {%1631..%1637},
      ]) 

/home/tau/tmp/zig/src/Type.zig:3122:22: 0x2d01de5 in errorSetNames (zig)
            .signed => try pt.intValue(dest_ty, 0),
                     ^
/home/tau/tmp/zig/src/Sema.zig:23186:53: 0x2a00654 in zirErrorCast (zig)
            .val = if (addr == 0) .none else (try pt.ptrIntValue(ptr_ty.childType(zcu), addr)).toIntern(),
                                                    ^
/home/tau/tmp/zig/src/Sema.zig:1367:65: 0x25c7d4e in analyzeBodyInner (zig)
                    .shl_with_overflow  => try sema.zirOverflowArithmetic(block, extended, extended.opcode),
                                                                ^
/home/tau/tmp/zig/src/Sema.zig:998:26: 0x291cc14 in analyzeFnBody (zig)

                         ^
/home/tau/tmp/zig/src/Zcu/PerThread.zig:2704:23: 0x256a704 in analyzeFnBodyInner (zig)
        else => |e| return e,
                      ^
/home/tau/tmp/zig/src/Zcu/PerThread.zig:1643:40: 0x21f0142 in analyzeFuncBody (zig)

                                       ^
/home/tau/tmp/zig/src/Zcu/PerThread.zig:1563:66: 0x1eb5615 in ensureFuncBodyUpToDate (zig)
    };
                                                                 ^
/home/tau/tmp/zig/src/Sema.zig:35793:38: 0x25dac60 in resolveInferredErrorSet (zig)
            "struct '{}' depends on itself",
                                     ^
/home/tau/tmp/zig/src/Sema.zig:32546:69: 0x2a26c1f in analyzeIsNonErrComptimeOnly (zig)
    const child_ty = ptr_ty.childType(zcu);
                                                                    ^
/home/tau/tmp/zig/src/Sema.zig:32575:56: 0x2db6db6 in analyzeIsNonErr (zig)
    if (payload_ty.zigTypeTag(zcu) == .noreturn) {
                                                       ^
/home/tau/tmp/zig/src/Sema.zig:19342:32: 0x2994fce in zirIsNonErr (zig)
fn zirIsNonNullPtr(
                               ^
/home/tau/tmp/zig/src/Sema.zig:1180:66: 0x25c147c in analyzeBodyInner (zig)
            .func_fancy                   => try sema.zirFuncFancy(block, inst),
                                                                 ^
/home/tau/tmp/zig/src/Sema.zig:6238:34: 0x2dd70c5 in resolveBlockBody (zig)
) CompileError!Air.Inst.Ref {
                                 ^
/home/tau/tmp/zig/src/Sema.zig:6215:33: 0x2a217ac in zirBlock (zig)
        .src_base_inst = parent_block.src_base_inst,
                                ^
/home/tau/tmp/zig/src/Sema.zig:1670:37: 0x25cac25 in analyzeBodyInner (zig)

                                    ^
/home/tau/tmp/zig/src/Sema.zig:6238:34: 0x2dd70c5 in resolveBlockBody (zig)
) CompileError!Air.Inst.Ref {
                                 ^
/home/tau/tmp/zig/src/Sema.zig:10906:45: 0x2dcee65 in resolveProngComptime (zig)
                );
                                            ^
/home/tau/tmp/zig/src/Sema.zig:13396:36: 0x2dd91f4 in resolveSwitchComptime (zig)
        special.has_tag_capture,
                                   ^
/home/tau/tmp/zig/src/Sema.zig:13224:34: 0x2dce496 in resolveSwitchComptimeLoop (zig)
            multi_cases_len,
                                 ^
/home/tau/tmp/zig/src/Sema.zig:12431:49: 0x29a4d8e in zirSwitchBlock (zig)
                    special,
                                                ^
/home/tau/tmp/zig/src/Sema.zig:1203:69: 0x25c19da in analyzeBodyInner (zig)
            .ret_err_value_code           => try sema.zirRetErrValueCode(inst),
                                                                    ^
/home/tau/tmp/zig/src/Sema.zig:998:26: 0x291cc14 in analyzeFnBody (zig)

                         ^
/home/tau/tmp/zig/src/Sema.zig:8211:27: 0x2a3de6b in analyzeCall (zig)
                const param_name = zir_datas[@intFromEnum(inst)].str_tok.get(sema.code);
                          ^
/home/tau/tmp/zig/src/Sema.zig:7207:43: 0x29883f9 in zirCall__anon_451992 (zig)
        .num_args = args_len,
                                          ^
/home/tau/tmp/zig/src/Sema.zig:1136:62: 0x25c09d1 in analyzeBodyInner (zig)
            .bit_not                      => try sema.zirBitNot(block, inst),
                                                             ^
/home/tau/tmp/zig/src/Sema.zig:998:26: 0x291cc14 in analyzeFnBody (zig)

                         ^
/home/tau/tmp/zig/src/Sema.zig:8211:27: 0x2a3de6b in analyzeCall (zig)
                const param_name = zir_datas[@intFromEnum(inst)].str_tok.get(sema.code);
                          ^
/home/tau/tmp/zig/src/Sema.zig:7207:43: 0x29883f9 in zirCall__anon_451992 (zig)
        .num_args = args_len,
                                          ^
/home/tau/tmp/zig/src/Sema.zig:1136:62: 0x25c09d1 in analyzeBodyInner (zig)
            .bit_not                      => try sema.zirBitNot(block, inst),
                                                             ^
/home/tau/tmp/zig/src/Sema.zig:1016:30: 0x221e74e in analyzeInlineBody (zig)
/// return `error.ComptimeBreak`. If `block.isComptime()`, this function will never return `null`.
                             ^
/home/tau/tmp/zig/src/Sema.zig:1049:39: 0x1ec6001 in resolveInlineBody (zig)
/// body at comptime to a single result value.
                                      ^
/home/tau/tmp/zig/src/Sema.zig:7514:65: 0x2e4f596 in analyzeArg (zig)

                                                                ^
/home/tau/tmp/zig/src/Sema.zig:7750:41: 0x2a36b24 in analyzeCall (zig)
            break :ty param_ty;
                                        ^
/home/tau/tmp/zig/src/Sema.zig:7207:43: 0x29894d8 in zirCall__anon_451994 (zig)
        .num_args = args_len,
                                          ^
/home/tau/tmp/zig/src/Sema.zig:1137:62: 0x25c0a0c in analyzeBodyInner (zig)
            .bit_or                       => try sema.zirBitwise(block, inst, .bit_or),
                                                             ^
/home/tau/tmp/zig/src/Sema.zig:998:26: 0x291cc14 in analyzeFnBody (zig)

                         ^
/home/tau/tmp/zig/src/Zcu/PerThread.zig:2704:23: 0x256a704 in analyzeFnBodyInner (zig)
        else => |e| return e,
                      ^
/home/tau/tmp/zig/src/Zcu/PerThread.zig:1643:40: 0x21f0142 in analyzeFuncBody (zig)

                                       ^
/home/tau/tmp/zig/src/Zcu/PerThread.zig:1563:66: 0x1eb5615 in ensureFuncBodyUpToDate (zig)
    };
                                                                 ^
/home/tau/tmp/zig/src/Compilation.zig:3737:38: 0x1c97861 in processOneJob (zig)

                                     ^
/home/tau/tmp/zig/src/Compilation.zig:3674:30: 0x1b2ad5d in performAllTheWorkInner (zig)
        // https://github.com/llvm/llvm-project/issues/43698#issuecomment-2542660611
                             ^
/home/tau/tmp/zig/src/Compilation.zig:3533:36: 0x1a08def in performAllTheWork (zig)
            referenced_by = ref.referencer;
                                   ^
/home/tau/tmp/zig/src/Compilation.zig:2261:31: 0x1a01cc8 in update (zig)
                comp.root_name,
                              ^
/home/tau/tmp/zig/src/main.zig:4474:20: 0x1a3931d in updateModule (zig)
            // ASLR is probably a good default for better debugging experience/programming
                   ^
/home/tau/tmp/zig/src/main.zig:3664:21: 0x1a6f7f5 in buildOutputType (zig)
            var server = try addr.listen(.{
                    ^
/home/tau/tmp/zig/src/main.zig:264:31: 0x19407a6 in mainArgs (zig)
        }
                              ^
/home/tau/tmp/zig/src/main.zig:205:20: 0x193d86a in main (zig)
        return mainArgs(gpa_tracy.allocator(), arena, args);
                   ^
/home/tau/tmp/zig/lib/std/start.zig:656:37: 0x193d0f2 in posixCallMainAndExit (zig)
            const result = root.main() catch |err| {
                                    ^
/home/tau/tmp/zig/lib/std/start.zig:271:5: 0x193ccdd in _start (zig)
    asm volatile (switch (native_arch) {
    ^

Expected Behavior

Likely compile error as there's no known error set.