We’re making a significant change to Mojo’s syntax before completing Phase 1 of the Mojo roadmap: renaming the alias keyword to comptimefor accuracy and consistency. :bullseye: Quick Summary alias was chosen early in Mojo’s development, but as the language has evolved, we’ve realized it doesn’t acc…

All right, just to give everyone a heads up. After quite a bit of debate, we’re moving forward with implementing ‘comptime’ in Mojo. In today’s nightly, and in the 25.7 release (next week) Mojo compiler will take both alias and comptime as synonyms. Error messages, examples and documentation will b…

The term “bind” means “give an identifier a meaning” . Doesn’t seem right for this use case.

The meaning in other languages is “static address”, whereas an alias could be described as a static value, or static constant. If you take this perspective, it seems reasonable that static x = 0 could denote a static value, whereas static var x = 0 could denote a static variable. If Mojo still had …

static is indeed a strong contender, it is appealing on many fronts. It deserves a consideration. I agree with Owen that static implies storage at runtime (per the C and Rust meanings). Specifically, I think it would look counterintuitive when used together with the “alias materialization” concept…

I am not a big fan of static. In my opinion, the keyword is ambiguous, it could either means that the object is statically-allocated or the value is statically-evaluated. The fact is that the keyword has already been widely used for “statically-allocated” objects, yet a mojo alias is a statically-ev…

[image] denis: Currently an alias is “materialized” (explicitly or implicitly) at a place of use. Exaggerated example: the following creates two LLVM store ops in the loop, creating two copies of the lookup table: … My point is, static X .. = computeLookupTable() strongly suggests that X is a …

Given that, I don’t know how bad it would truly be to tweak the norm of what “static” mean Sure, but what keyword should we pick to denote statically allocated objects in the future? The current behaviour of alias is surely not how we want it to work long-term, right? It seems like something th…

[image] Peiming: what keyword should we pick to denote statically allocated objects in the future? Earlier in the thread we discussed using global for this purpose (i.e. mutable variables with static storage). It’s an existing keyword in Python. [image] Peiming: To me, what you really ne…

[image] Nick: [image] denis: My point is, static X .. = computeLookupTable() strongly suggests that X is a value computed and stored in static storage (in RODATA) and that X[j]does not inline-substitute the whole array there. The current behaviour of alias is surely not how we want it to …

I perhaps wasn’t clear earlier, but I am wondering why the compiler can’t just automatically do the equivalent of global g = paramVal in the cases where the function needs to read paramVal’s value and/or address at runtime. (This would happen once per function instantiation distinct value of paramVa…

There are several important questions to ask before we decide whether compiler should/can always automatically turn an alias into global IMO. Are all types materializable to globals? Say Trees/Linked Lists (maybe?). Should the value always have the same type before/after materializing into globals…

Mojo change: renaming `alias` to `comptime`

Mojo

christoph_schlumpf (Christoph Schlumpf) November 14, 2025, 9:14am 45

Somehow related because it also proposes a renaming: Mojo proposal: renaming `read` to `immut`

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Feedback request: Should Mojo adopt "specialization" for what we currently call "parameters"? Mojo mojo-1_0	45	1469	July 20, 2026
Idea: comptime var Language Design	3	136	February 3, 2026
How do you put bytes into rodata? Mojo	15	492	November 3, 2025
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Mojo change: renaming `alias` to `comptime`

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