Merge #1034

1034: HIR diagnostics API r=matklad a=matklad

This PR introduces diagnostics API for HIR, so we can now start issuing errors and warnings! Here are requirements that this solution aims to fulfill:

* structured diagnostics: rather than immediately rendering error to string, we provide a well-typed blob of data with error-description. These data is used by IDE to provide fixes
* open set diagnostics: there's no single enum with all possible diagnostics, which hopefully should result in better modularity

The `Diagnostic` trait describes "a diagnostic", which can be downcast to a specific diagnostic kind. Diagnostics are expressed in terms of macro-expanded syntax tree: they store pointers to syntax nodes. Diagnostics are self-contained: you don't need any context, besides `db`, to fully understand the meaning of a diagnostic. 

Because diagnostics are tied to the source, we can't store them in salsa. So subsystems like type-checking produce subsystem-local diagnostic (which is a closed `enum`), which is expressed in therms of subsystem IR. A separate step converts these proto-diagnostics into `Diagnostic`, by merging them with source-maps.

Note that this PR stresses type-system quite a bit: we now type-check every function in open files to compute errors!

Discussion on Zulip: https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/Diagnostics.20API

Co-authored-by: Aleksey Kladov <[email protected]>

1 files changed, 2 insertions, 17 deletions

diff --git a/crates/ra_hir/src/code_model_impl/module.rs b/crates/ra_hir/src/code_model_impl/module.rs
index 52a33e981..14237060c 100644
--- a/crates/ra_hir/src/code_model_impl/module.rs
+++ b/crates/ra_hir/src/code_model_impl/module.rs
@@ -1,8 +1,8 @@
 use ra_db::FileId;
-use ra_syntax::{ast, SyntaxNode, TreeArc, AstNode};
+use ra_syntax::{ast, TreeArc, AstNode};
 
 use crate::{
-    Module, ModuleSource, Problem, Name,
+    Module, ModuleSource, Name,
     nameres::{CrateModuleId, ImportId},
     HirDatabase, DefDatabase,
     HirFileId, SourceItemId,
@@ -108,19 +108,4 @@ impl Module {
         let parent_id = def_map[self.module_id].parent?;
         Some(self.with_module_id(parent_id))
     }
-
-    pub(crate) fn problems_impl(
-        &self,
-        db: &impl HirDatabase,
-    ) -> Vec<(TreeArc<SyntaxNode>, Problem)> {
-        let def_map = db.crate_def_map(self.krate);
-        let (my_file_id, _) = self.definition_source(db);
-        // FIXME: not entirely corret filterint by module
-        def_map
-            .problems()
-            .iter()
-            .filter(|(source_item_id, _problem)| my_file_id == source_item_id.file_id)
-            .map(|(source_item_id, problem)| (db.file_item(*source_item_id), problem.clone()))
-            .collect()
-    }
 }