[SAOC 2025] Separate Semantic Routines from AST Nodes Weekly Update #8

[Mohamed El Shorbagy]

# Summary of Progress (Nov. 03 - Nov. 10)

This week I worked on the following:

1. Filtering the dependency graph so that it contains only paths 
to semantic files (forming a dependency tree). This could be 
achieved through simple depth-first traversal on the complete 
graph, taking the file of interest as the source node. Some 
AST-related files not only have semantic dependencies near the 
root but also really deep in the tree. The proper approach we 
thought of is to tackle the dependencies near the root first in 
all files, then go breadth-first.

2. `mtype.d` is still dependent on `typesem.d` in many places, so 
it should be tackled one at a time. `Type.toBaseType` is such an 
example. This function is used in many places across the frontend 
code; however, we are interested in the AST-related files, which 
are:
    - `cond.d`, specifically in `StaticForEach.ready` (see [Merged 
PR](https://github.com/dlang/dmd/pull/22065/files)).
    - `dtemplate.d`, specifically `reliesOn*` functions (see 
[Merged PR](https://github.com/dlang/dmd/pull/22064)).
    - `expression.d` in some free functions (see [Merged 
PR](https://github.com/dlang/dmd/pull/22066/)) and `normalize`, 
which is tricky. `toInteger`, `toUInteger`, `toReal`, and 
`toComplex` are all dependent on `normalize`, and they are 
handled [here](https://github.com/dlang/dmd/pull/22073) and 
[here](https://github.com/dlang/dmd/pull/22076). The trick is 
that the constructor of `IntegerExp` still depends on that 
function, so I am still figuring out the best approach for that.