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​​Name Resolution, Salsa Brainstorming

​​Goal: Make name resolution incremental

​​

​​Queries

• ​​Name resolution results

• ​​Expansion of a macro

​​Scenario #1

​​

​​// crate C0

​​


​​lazy_static! { // ID L0

​​    static ref HASHMAP: HashMap<u32, &'static str> = {

​​        let mut m = HashMap::new();

​​        m.insert(0, "foo");

​​//        m.insert(1, "bar"); <-- change is to alter this line

​​        m.insert(2, "baz");

​​        m

​​    };

​​}

​​

​​Concept

• ​​name_resolution_results(C0): Map<Identifier, Id>​

• ​​fixed point process

• ​​to expand macro invocation L0​ we have to figure out what lazy_static​ refers to

• ​​we use the map we are building, we get back the id of a definition D0​

• ​​expand_macro_invocation(D0, L0)​ // source D0, arguments L0

• ​​but what are the arguments to this query — particularly the id of the **invocation**

• ​​challenge is that we need ids that can map to the result of expansion

​​

• ​​what does the id map to

• ​​span in a concrete file

• ​​span into the result of a macro expansion (D0, L0)

​​

• ​​recursive macro invocation:

• ​​macro A expands to b!(…)​

• ​​expand_macro_invocation(a_def, a_use_site)​

• ​​make an id (a_def, a_use_site)​ and call it b_use_site​

​​

• ​​name resolution

• ​​definitions_from_macro_invocation(a_def, a_use_site)​

• ​​vec![b_use_site]​

• ​​definitions_from_macro_invocation(b_def, b_use_site)​

• ​​
  

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