Module dimension_check 

Dimension-aware static analysis — rejects dimension-incoherent quantity arithmetic at COMPILE time, before any code is generated. 2 meters + 1 gram is a type error, not a runtime panic: a length and a mass have no common dimension, so adding them cannot mean anything.

This is a dedicated pass in the crate::analysis::escape::EscapeChecker / crate::analysis::ownership mold, wired as a gate in compile.rs. It runs on the SAME AST the interpreter and the AOT compiler share, so a dimension error is reported identically on every tier before execution.

Soundness is conservative. Every quantity value already carries its dimension at runtime; this pass only adds a static rejection where it can PROVE incompatibility — i.e. when both operands’ dimensions are statically known and differ. A quantity of unknown dimension (a Quantity function parameter, a collection element, a value from an opaque call) is treated as dimension-polymorphic and deferred to the existing runtime check. So this pass never rejects a correct program; it only promotes provable runtime failures to compile-time errors.

Structs

DimensionChecker

DimensionError

A dimension coherence error, with the same shape the other analysis passes use so compile.rs can convert it to a ParseError uniformly.