fix(forge): debugger should load sourcemaps by file_id

[emo-eth]

Motivation

Summary from #7043:

ContractSources is a mapping of name -> id -> (source code, bytecode)

In src_map, the source for the contract is looked up by name. Since this may return multiple contracts with the same name, the entries are iterated over and the SourceElement's index is compared to the file_id of the current contract source. If they match, the source code is returned.

The problem is that this will never return source code for inherited contracts, because it is only loading source code for (contracts with the same name as) the contract being invoked; if the SourceElement points to a different index (aka file_id), it will never match any of the contract sources loaded from ContractSources.

ContractSources should maintain an index both of name -> id -> (source, bytecode) and id -> (source, bytecode) for looking up cross-source sourcemaps.

Solution

ContractSources now also maintains a mapping of file_id/index -> (source code, bytecode). When the loaded file_id does not match source_element.index, it looks up the contract source using the source_element's index.

I could use some help testing this – it looks to me like the debug.rs test doesn't actually make any assertions, so I don't have much to go off of.

Closes #7043

Before:

After:

[onbjerg]

hyped for this

[DaniPopes]

Needs cargo +nightly fmt

[DaniPopes]

LGTM, thanks! Pending @onbjerg

[mattsse]

ty!
lgtm