internal: move diagnostics to hir

The idea here is to eventually get rid of `dyn Diagnostic` and
`DiagnosticSink` infrastructure altogether, and just have a `enum
hir::Diagnostic` instead.

The problem with `dyn Diagnostic` is that it is defined in the lowest
level of the stack (hir_expand), but is used by the highest level (ide).

As a first step, we free hir_expand and hir_def from `dyn Diagnostic`
and kick the can up to `hir_ty`, as an intermediate state. The plan is
then to move DiagnosticSink similarly to the hir crate, and, as final
third step, remove its usage from the ide.

One currently unsolved problem is testing. You can notice that the test
which checks precise diagnostic ranges, unresolved_import_in_use_tree,
was moved to the ide layer. Logically, only IDE should have the infra to
render a specific range.

At the same time, the range is determined with the data produced in
hir_def and hir crates, so this layering is rather unfortunate. Working
on hir_def shouldn't require compiling `ide` for testing.

crates/hir/src/lib.rs

@@ -35,12 +35,18 @@ use std::{iter, sync::Arc};
 
 use arrayvec::ArrayVec;
 use base_db::{CrateDisplayName, CrateId, Edition, FileId};
+use diagnostics::{
+    InactiveCode, MacroError, UnresolvedExternCrate, UnresolvedImport, UnresolvedMacroCall,
+    UnresolvedModule, UnresolvedProcMacro,
+};
 use either::Either;
 use hir_def::{
     adt::{ReprKind, VariantData},
+    body::BodyDiagnostic,
     expr::{BindingAnnotation, LabelId, Pat, PatId},
     item_tree::ItemTreeNode,
     lang_item::LangItemTarget,
+    nameres,
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
     src::HasSource as _,
@@ -50,11 +56,12 @@ use hir_def::{
     LocalEnumVariantId, LocalFieldId, Lookup, ModuleId, StaticId, StructId, TraitId, TypeAliasId,
     TypeParamId, UnionId,
 };
-use hir_expand::{diagnostics::DiagnosticSink, name::name, MacroDefKind};
+use hir_expand::{name::name, MacroCallKind, MacroDefKind};
 use hir_ty::{
     autoderef,
     consteval::ConstExt,
     could_unify,
+    diagnostics_sink::DiagnosticSink,
     method_resolution::{self, def_crates, TyFingerprint},
     primitive::UintTy,
     subst_prefix,
@@ -65,11 +72,12 @@ use hir_ty::{
     WhereClause,
 };
 use itertools::Itertools;
+use nameres::diagnostics::DefDiagnosticKind;
 use rustc_hash::FxHashSet;
 use stdx::{format_to, impl_from};
 use syntax::{
     ast::{self, AttrsOwner, NameOwner},
-    AstNode, SmolStr,
+    AstNode, AstPtr, SmolStr, SyntaxKind, SyntaxNodePtr,
 };
 use tt::{Ident, Leaf, Literal, TokenTree};
 
@@ -442,7 +450,137 @@ impl Module {
             format!("{:?}", self.name(db).map_or("<unknown>".into(), |name| name.to_string()))
         });
         let def_map = self.id.def_map(db.upcast());
-        def_map.add_diagnostics(db.upcast(), self.id.local_id, sink);
+        for diag in def_map.diagnostics() {
+            if diag.in_module != self.id.local_id {
+                // FIXME: This is accidentally quadratic.
+                continue;
+            }
+            match &diag.kind {
+                DefDiagnosticKind::UnresolvedModule { ast: declaration, candidate } => {
+                    let decl = declaration.to_node(db.upcast());
+                    sink.push(UnresolvedModule {
+                        file: declaration.file_id,
+                        decl: AstPtr::new(&decl),
+                        candidate: candidate.clone(),
+                    })
+                }
+                DefDiagnosticKind::UnresolvedExternCrate { ast } => {
+                    let item = ast.to_node(db.upcast());
+                    sink.push(UnresolvedExternCrate {
+                        file: ast.file_id,
+                        item: AstPtr::new(&item),
+                    });
+                }
+
+                DefDiagnosticKind::UnresolvedImport { ast, index } => {
+                    let use_item = ast.to_node(db.upcast());
+                    let hygiene = Hygiene::new(db.upcast(), ast.file_id);
+                    let mut cur = 0;
+                    let mut tree = None;
+                    ModPath::expand_use_item(
+                        db.upcast(),
+                        InFile::new(ast.file_id, use_item),
+                        &hygiene,
+                        |_mod_path, use_tree, _is_glob, _alias| {
+                            if cur == *index {
+                                tree = Some(use_tree.clone());
+                            }
+
+                            cur += 1;
+                        },
+                    );
+
+                    if let Some(tree) = tree {
+                        sink.push(UnresolvedImport { file: ast.file_id, node: AstPtr::new(&tree) });
+                    }
+                }
+
+                DefDiagnosticKind::UnconfiguredCode { ast, cfg, opts } => {
+                    let item = ast.to_node(db.upcast());
+                    sink.push(InactiveCode {
+                        file: ast.file_id,
+                        node: AstPtr::new(&item).into(),
+                        cfg: cfg.clone(),
+                        opts: opts.clone(),
+                    });
+                }
+
+                DefDiagnosticKind::UnresolvedProcMacro { ast } => {
+                    let mut precise_location = None;
+                    let (file, ast, name) = match ast {
+                        MacroCallKind::FnLike { ast_id, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
+                        }
+                        MacroCallKind::Derive { ast_id, derive_name, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+
+                            // Compute the precise location of the macro name's token in the derive
+                            // list.
+                            // FIXME: This does not handle paths to the macro, but neither does the
+                            // rest of r-a.
+                            let derive_attrs =
+                                node.attrs().filter_map(|attr| match attr.as_simple_call() {
+                                    Some((name, args)) if name == "derive" => Some(args),
+                                    _ => None,
+                                });
+                            'outer: for attr in derive_attrs {
+                                let tokens =
+                                    attr.syntax().children_with_tokens().filter_map(|elem| {
+                                        match elem {
+                                            syntax::NodeOrToken::Node(_) => None,
+                                            syntax::NodeOrToken::Token(tok) => Some(tok),
+                                        }
+                                    });
+                                for token in tokens {
+                                    if token.kind() == SyntaxKind::IDENT
+                                        && token.text() == derive_name.as_str()
+                                    {
+                                        precise_location = Some(token.text_range());
+                                        break 'outer;
+                                    }
+                                }
+                            }
+
+                            (
+                                ast_id.file_id,
+                                SyntaxNodePtr::from(AstPtr::new(&node)),
+                                Some(derive_name.clone()),
+                            )
+                        }
+                    };
+                    sink.push(UnresolvedProcMacro {
+                        file,
+                        node: ast,
+                        precise_location,
+                        macro_name: name,
+                    });
+                }
+
+                DefDiagnosticKind::UnresolvedMacroCall { ast, path } => {
+                    let node = ast.to_node(db.upcast());
+                    sink.push(UnresolvedMacroCall {
+                        file: ast.file_id,
+                        node: AstPtr::new(&node),
+                        path: path.clone(),
+                    });
+                }
+
+                DefDiagnosticKind::MacroError { ast, message } => {
+                    let (file, ast) = match ast {
+                        MacroCallKind::FnLike { ast_id, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                        }
+                        MacroCallKind::Derive { ast_id, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                        }
+                    };
+                    sink.push(MacroError { file, node: ast, message: message.clone() });
+                }
+            }
+        }
         for decl in self.declarations(db) {
             match decl {
                 crate::ModuleDef::Function(f) => f.diagnostics(db, sink),
@@ -865,7 +1003,37 @@ impl Function {
 
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
         let krate = self.module(db).id.krate();
-        hir_def::diagnostics::validate_body(db.upcast(), self.id.into(), sink);
+
+        let source_map = db.body_with_source_map(self.id.into()).1;
+        for diag in source_map.diagnostics() {
+            match diag {
+                BodyDiagnostic::InactiveCode { node, cfg, opts } => sink.push(InactiveCode {
+                    file: node.file_id,
+                    node: node.value.clone(),
+                    cfg: cfg.clone(),
+                    opts: opts.clone(),
+                }),
+                BodyDiagnostic::MacroError { node, message } => sink.push(MacroError {
+                    file: node.file_id,
+                    node: node.value.clone().into(),
+                    message: message.to_string(),
+                }),
+                BodyDiagnostic::UnresolvedProcMacro { node } => sink.push(UnresolvedProcMacro {
+                    file: node.file_id,
+                    node: node.value.clone().into(),
+                    precise_location: None,
+                    macro_name: None,
+                }),
+                BodyDiagnostic::UnresolvedMacroCall { node, path } => {
+                    sink.push(UnresolvedMacroCall {
+                        file: node.file_id,
+                        node: node.value.clone(),
+                        path: path.clone(),
+                    })
+                }
+            }
+        }
+
         hir_ty::diagnostics::validate_module_item(db, krate, self.id.into(), sink);
         hir_ty::diagnostics::validate_body(db, self.id.into(), sink);
     }