Unreachable in analyze.cpp from comptime function call that takes optional error parameter

[alinebee]

Zig Version

0.10.0-dev.1447+1bd595cee

Steps to Reproduce

Compile and test the following program with zig test:

fn doSomethingWithRequiredError(_: anyerror) void {}
fn doSomethingWithOptionalError(_: ?anyerror) void {}

test "✅ Function call that takes required error compiles when called at runtime" {
    doSomethingWithRequiredError(error.OutOfMemory);
}

test "✅ Function call that takes required error compiles when called at compile time" {
    comptime doSomethingWithRequiredError(error.OutOfMemory);
}

test "✅ Function call that takes optional error compiles when called at runtime" {
    doSomethingWithOptionalError(error.OutOfMemory);
}

test "💥 Function call that takes optional error fails to compile when called at compile time" {
    // Comment this out and compilation will succeed
    comptime doSomethingWithOptionalError(error.OutOfMemory);
}

Expected Behavior

Running zig test on the program above compiles and executes the tests, or fails with a compilation error on the offending line.

Actual Behavior

Running zig test on the program above panics with the following message:

[snip]/zig/src/stage1/analyze.cpp:5884 in can_mutate_comptime_var_state. This is a bug in the Zig compiler.thread 2877888 panic: 
[snip]/zig/src/stage1.zig:178:5: 0x1044b114f in stage2_panic (zig1)
    @panic(ptr[0..len]);
    ^
???:?:?: 0x1096db95f in __Z9zig_panicPKcz (???)
???:?:?: 0x10532b933 in __ZL29can_mutate_comptime_var_stateP8ZigValue (???)
???:?:?: 0x10532b86f in __ZL29can_mutate_comptime_var_stateP8ZigValue (???)
???:?:?: 0x10532b44b in __Z17fn_eval_cacheableP5ScopeP7ZigType (???)
???:?:?: 0x105423ab3 in __ZL18ir_analyze_fn_callP9IrAnalyzeP5ScopeP7AstNodeP5ZigFnP7ZigTypeP13Stage1AirInstSA_S4_12CallModifierSA_S4_bPSA_mSA_P9ResultLoc (???)
???:?:?: 0x10542336f in __ZL22ir_analyze_fn_call_srcP9IrAnalyzeP17Stage1ZirInstCallP5ZigFnP7ZigTypeP13Stage1AirInstS8_P7AstNode12CallModifier (???)
???:?:?: 0x1053e2e23 in __ZL27ir_analyze_instruction_callP9IrAnalyzeP17Stage1ZirInstCall (???)
???:?:?: 0x1053d7693 in __ZL27ir_analyze_instruction_baseP9IrAnalyzeP13Stage1ZirInst (???)
???:?:?: 0x1053d68e7 in __Z10ir_analyzeP7CodeGenP9Stage1ZirP9Stage1AirPmS5_P7ZigTypeP7AstNodeP8ZigValueP5ZigFn (???)
???:?:?: 0x105339ee7 in __ZL13analyze_fn_irP7CodeGenP5ZigFnP7AstNode (???)
???:?:?: 0x1053288b3 in __ZL15analyze_fn_bodyP7CodeGenP5ZigFn (???)
???:?:?: 0x10532972b in __Z16semantic_analyzeP7CodeGen (???)
???:?:?: 0x10538a8eb in __ZL15gen_root_sourceP7CodeGen (???)
???:?:?: 0x10538942b in __Z20codegen_build_objectP7CodeGen (???)
???:?:?: 0x10545c1b7 in _zig_stage1_build_object (???)
[snip]/zig/src/stage1.zig:149:32: 0x1048501c7 in Module.build_object (zig1)
        zig_stage1_build_object(mod);
                               ^
[snip]/zig/src/Compilation.zig:5010:31: 0x10482df37 in Compilation.updateStage1Module (zig1)
    stage1_module.build_object();
                              ^
[snip]/zig/src/Compilation.zig:3076:36: 0x10462901b in Compilation.processOneJob (zig1)
            comp.updateStage1Module(main_progress_node) catch |err| {
                                   ^
[snip]/zig/src/Compilation.zig:2685:30: 0x10461e21b in Compilation.performAllTheWork (zig1)
            try processOneJob(self, work_item, main_progress_node);
                             ^
[snip]/zig/src/Compilation.zig:2090:31: 0x104618bbf in Compilation.update (zig1)
    try comp.performAllTheWork();
                              ^
[snip]/zig/src/main.zig:3094:20: 0x1045b7e9f in main.updateModule (zig1)
    try comp.update();
                   ^
[snip]/zig/src/main.zig:2781:17: 0x1044e6313 in main.buildOutputType (zig1)
    updateModule(gpa, comp, hook) catch |err| switch (err) {
                ^
[snip]/zig/src/main.zig:216:31: 0x1044afe9b in main.mainArgs (zig1)
        return buildOutputType(gpa, arena, args, .zig_test);
                              ^
[snip]/zig/src/stage1.zig:48:24: 0x1044af7c3 in main (zig1)
        stage2.mainArgs(gpa, arena, args) catch unreachable;