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 <aleksey.kladov@gmail.com>

crates/ra_hir/src/code_model_api.rs

@@ -1,8 +1,7 @@
 use std::sync::Arc;
 
-use relative_path::RelativePathBuf;
 use ra_db::{CrateId, SourceRootId, Edition};
-use ra_syntax::{ast::self, TreeArc, SyntaxNode};
+use ra_syntax::{ast::self, TreeArc};
 
 use crate::{
     Name, ScopesWithSourceMap, Ty, HirFileId,
@@ -17,6 +16,7 @@ use crate::{
     ids::{FunctionId, StructId, EnumId, AstItemDef, ConstId, StaticId, TraitId, TypeId},
     impl_block::ImplBlock,
     resolve::Resolver,
+    diagnostics::DiagnosticSink,
 };
 
 /// hir::Crate describes a single crate. It's the main interface with which
@@ -95,11 +95,6 @@ pub enum ModuleSource {
     Module(TreeArc<ast::Module>),
 }
 
-#[derive(Clone, Debug, Hash, PartialEq, Eq)]
-pub enum Problem {
-    UnresolvedModule { candidate: RelativePathBuf },
-}
-
 impl Module {
     /// Name of this module.
     pub fn name(&self, db: &impl HirDatabase) -> Option<Name> {
@@ -171,8 +166,24 @@ impl Module {
         db.crate_def_map(self.krate)[self.module_id].scope.clone()
     }
 
-    pub fn problems(&self, db: &impl HirDatabase) -> Vec<(TreeArc<SyntaxNode>, Problem)> {
-        self.problems_impl(db)
+    pub fn diagnostics(&self, db: &impl HirDatabase, sink: &mut DiagnosticSink) {
+        db.crate_def_map(self.krate).add_diagnostics(db, self.module_id, sink);
+        for decl in self.declarations(db) {
+            match decl {
+                crate::ModuleDef::Function(f) => f.diagnostics(db, sink),
+                crate::ModuleDef::Module(f) => f.diagnostics(db, sink),
+                _ => (),
+            }
+        }
+
+        for impl_block in self.impl_blocks(db) {
+            for item in impl_block.items(db) {
+                match item {
+                    crate::ImplItem::Method(f) => f.diagnostics(db, sink),
+                    _ => (),
+                }
+            }
+        }
     }
 
     pub fn resolver(&self, db: &impl HirDatabase) -> Resolver {
@@ -519,6 +530,10 @@ impl Function {
         let r = if !p.params.is_empty() { r.push_generic_params_scope(p) } else { r };
         r
     }
+
+    pub fn diagnostics(&self, db: &impl HirDatabase, sink: &mut DiagnosticSink) {
+        self.infer(db).add_diagnostics(db, *self, sink);
+    }
 }
 
 impl Docs for Function {

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()
-    }
 }

crates/ra_hir/src/diagnostics.rs

@@ -0,0 +1,115 @@
+use std::{fmt, any::Any};
+
+use ra_syntax::{SyntaxNodePtr, TreeArc, AstPtr, TextRange, ast, SyntaxNode};
+use relative_path::RelativePathBuf;
+
+use crate::{HirFileId, HirDatabase};
+
+/// Diagnostic defines hir API for errors and warnings.
+///
+/// It is used as a `dyn` object, which you can downcast to a concrete
+/// diagnostic. DiagnosticSink are structured, meaning that they include rich
+/// information which can be used by IDE to create fixes. DiagnosticSink are
+/// expressed in terms of macro-expanded syntax tree nodes (so, it's a bad idea
+/// to diagnostic in a salsa value).
+///
+/// Internally, various subsystems of hir produce diagnostics specific to a
+/// subsystem (typically, an `enum`), which are safe to store in salsa but do not
+/// include source locations. Such internal diagnostic are transformed into an
+/// instance of `Diagnostic` on demand.
+pub trait Diagnostic: Any + Send + Sync + fmt::Debug + 'static {
+    fn message(&self) -> String;
+    fn file(&self) -> HirFileId;
+    fn syntax_node_ptr(&self) -> SyntaxNodePtr;
+    fn highlight_range(&self) -> TextRange {
+        self.syntax_node_ptr().range()
+    }
+    fn as_any(&self) -> &(dyn Any + Send + 'static);
+}
+
+impl dyn Diagnostic {
+    pub fn syntax_node(&self, db: &impl HirDatabase) -> TreeArc<SyntaxNode> {
+        let source_file = db.hir_parse(self.file());
+        self.syntax_node_ptr().to_node(&source_file).to_owned()
+    }
+    pub fn downcast_ref<D: Diagnostic>(&self) -> Option<&D> {
+        self.as_any().downcast_ref()
+    }
+}
+
+pub struct DiagnosticSink<'a> {
+    callbacks: Vec<Box<dyn FnMut(&dyn Diagnostic) -> Result<(), ()> + 'a>>,
+    default_callback: Box<dyn FnMut(&dyn Diagnostic) + 'a>,
+}
+
+impl<'a> DiagnosticSink<'a> {
+    pub fn new(cb: impl FnMut(&dyn Diagnostic) + 'a) -> DiagnosticSink<'a> {
+        DiagnosticSink { callbacks: Vec::new(), default_callback: Box::new(cb) }
+    }
+
+    pub fn on<D: Diagnostic, F: FnMut(&D) + 'a>(mut self, mut cb: F) -> DiagnosticSink<'a> {
+        let cb = move |diag: &dyn Diagnostic| match diag.downcast_ref::<D>() {
+            Some(d) => {
+                cb(d);
+                Ok(())
+            }
+            None => Err(()),
+        };
+        self.callbacks.push(Box::new(cb));
+        self
+    }
+
+    pub(crate) fn push(&mut self, d: impl Diagnostic) {
+        let d: &dyn Diagnostic = &d;
+        for cb in self.callbacks.iter_mut() {
+            match cb(d) {
+                Ok(()) => return,
+                Err(()) => (),
+            }
+        }
+        (self.default_callback)(d)
+    }
+}
+
+#[derive(Debug)]
+pub struct NoSuchField {
+    pub file: HirFileId,
+    pub field: AstPtr<ast::NamedField>,
+}
+
+impl Diagnostic for NoSuchField {
+    fn message(&self) -> String {
+        "no such field".to_string()
+    }
+    fn file(&self) -> HirFileId {
+        self.file
+    }
+    fn syntax_node_ptr(&self) -> SyntaxNodePtr {
+        self.field.into()
+    }
+    fn as_any(&self) -> &(Any + Send + 'static) {
+        self
+    }
+}
+
+#[derive(Debug)]
+pub struct UnresolvedModule {
+    pub file: HirFileId,
+    pub decl: AstPtr<ast::Module>,
+    pub candidate: RelativePathBuf,
+}
+
+impl Diagnostic for UnresolvedModule {
+    fn message(&self) -> String {
+        "unresolved module".to_string()
+    }
+    fn file(&self) -> HirFileId {
+        self.file
+    }
+    fn syntax_node_ptr(&self) -> SyntaxNodePtr {
+        self.decl.into()
+    }
+    fn as_any(&self) -> &(Any + Send + 'static) {
+        self
+    }
+}

crates/ra_hir/src/expr.rs

@@ -5,7 +5,7 @@ use rustc_hash::FxHashMap;
 
 use ra_arena::{Arena, RawId, impl_arena_id, map::ArenaMap};
 use ra_syntax::{
-    SyntaxNodePtr, AstNode,
+    SyntaxNodePtr, AstPtr, AstNode,
     ast::{self, LoopBodyOwner, ArgListOwner, NameOwner, LiteralFlavor, TypeAscriptionOwner}
 };
 
@@ -54,6 +54,7 @@ pub struct BodySourceMap {
     expr_map_back: ArenaMap<ExprId, SyntaxNodePtr>,
     pat_map: FxHashMap<SyntaxNodePtr, PatId>,
     pat_map_back: ArenaMap<PatId, SyntaxNodePtr>,
+    field_map: FxHashMap<(ExprId, usize), AstPtr<ast::NamedField>>,
 }
 
 impl Body {
@@ -138,6 +139,10 @@ impl BodySourceMap {
     pub fn node_pat(&self, node: &ast::Pat) -> Option<PatId> {
         self.pat_map.get(&SyntaxNodePtr::new(node.syntax())).cloned()
     }
+
+    pub fn field_syntax(&self, expr: ExprId, field: usize) -> AstPtr<ast::NamedField> {
+        self.field_map[&(expr, field)].clone()
+    }
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -629,8 +634,10 @@ impl ExprCollector {
             }
             ast::ExprKind::StructLit(e) => {
                 let path = e.path().and_then(Path::from_ast);
+                let mut field_ptrs = Vec::new();
                 let fields = if let Some(nfl) = e.named_field_list() {
                     nfl.fields()
+                        .inspect(|field| field_ptrs.push(AstPtr::new(*field)))
                         .map(|field| StructLitField {
                             name: field
                                 .name_ref()
@@ -657,7 +664,11 @@ impl ExprCollector {
                     Vec::new()
                 };
                 let spread = e.spread().map(|s| self.collect_expr(s));
-                self.alloc_expr(Expr::StructLit { path, fields, spread }, syntax_ptr)
+                let res = self.alloc_expr(Expr::StructLit { path, fields, spread }, syntax_ptr);
+                for (i, ptr) in field_ptrs.into_iter().enumerate() {
+                    self.source_map.field_map.insert((res, i), ptr);
+                }
+                res
             }
             ast::ExprKind::FieldExpr(e) => {
                 let expr = self.collect_expr_opt(e.expr());

crates/ra_hir/src/lib.rs

@@ -35,6 +35,7 @@ mod expr;
 mod generics;
 mod docs;
 mod resolve;
+pub mod diagnostics;
 
 mod code_model_api;
 mod code_model_impl;
@@ -63,7 +64,7 @@ pub use self::{
 
 pub use self::code_model_api::{
     Crate, CrateDependency,
-    Module, ModuleDef, ModuleSource, Problem,
+    Module, ModuleDef, ModuleSource,
     Struct, Enum, EnumVariant,
     Function, FnSignature,
     StructField, FieldSource,

crates/ra_hir/src/mock.rs

@@ -9,7 +9,7 @@ use relative_path::RelativePathBuf;
 use test_utils::{parse_fixture, CURSOR_MARKER, extract_offset};
 use rustc_hash::FxHashMap;
 
-use crate::{db, HirInterner};
+use crate::{db, HirInterner, diagnostics::DiagnosticSink};
 
 pub const WORKSPACE: SourceRootId = SourceRootId(0);
 
@@ -70,6 +70,22 @@ impl MockDatabase {
         self.set_crate_graph(Arc::new(crate_graph))
     }
 
+    pub fn diagnostics(&self) -> String {
+        let mut buf = String::from("\n");
+        let mut files: Vec<FileId> = self.files.values().map(|&it| it).collect();
+        files.sort();
+        for file in files {
+            let module = crate::source_binder::module_from_file_id(self, file).unwrap();
+            module.diagnostics(
+                self,
+                &mut DiagnosticSink::new(|d| {
+                    buf += &format!("{:?}: {}\n", d.syntax_node(self).text(), d.message());
+                }),
+            )
+        }
+        buf
+    }
+
     fn from_fixture(fixture: &str) -> (MockDatabase, Option<FilePosition>) {
         let mut db = MockDatabase::default();
 

crates/ra_hir/src/nameres.rs

@@ -61,9 +61,11 @@ use ra_db::{FileId, Edition};
 use test_utils::tested_by;
 
 use crate::{
-    ModuleDef, Name, Crate, Module, Problem,
+    ModuleDef, Name, Crate, Module,
     DefDatabase, Path, PathKind, HirFileId,
     ids::{SourceItemId, SourceFileItemId, MacroCallId},
+    diagnostics::DiagnosticSink,
+    nameres::diagnostics::DefDiagnostic,
 };
 
 pub(crate) use self::raw::{RawItems, ImportId, ImportSourceMap};
@@ -85,7 +87,7 @@ pub struct CrateDefMap {
     macros: Arena<CrateMacroId, mbe::MacroRules>,
     public_macros: FxHashMap<Name, CrateMacroId>,
     macro_resolutions: FxHashMap<MacroCallId, (Crate, CrateMacroId)>,
-    problems: CrateDefMapProblems,
+    diagnostics: Vec<DefDiagnostic>,
 }
 
 impl std::ops::Index<CrateModuleId> for CrateDefMap {
@@ -125,21 +127,6 @@ pub(crate) struct ModuleData {
     pub(crate) definition: Option<FileId>,
 }
 
-#[derive(Default, Debug, PartialEq, Eq)]
-pub(crate) struct CrateDefMapProblems {
-    problems: Vec<(SourceItemId, Problem)>,
-}
-
-impl CrateDefMapProblems {
-    fn add(&mut self, source_item_id: SourceItemId, problem: Problem) {
-        self.problems.push((source_item_id, problem))
-    }
-
-    pub(crate) fn iter<'a>(&'a self) -> impl Iterator<Item = (&'a SourceItemId, &'a Problem)> + 'a {
-        self.problems.iter().map(|(s, p)| (s, p))
-    }
-}
-
 #[derive(Debug, Default, PartialEq, Eq, Clone)]
 pub struct ModuleScope {
     items: FxHashMap<Name, Resolution>,
@@ -212,7 +199,7 @@ impl CrateDefMap {
                 macros: Arena::default(),
                 public_macros: FxHashMap::default(),
                 macro_resolutions: FxHashMap::default(),
-                problems: CrateDefMapProblems::default(),
+                diagnostics: Vec::new(),
             }
         };
         let def_map = collector::collect_defs(db, def_map);
@@ -224,10 +211,6 @@ impl CrateDefMap {
         self.root
     }
 
-    pub(crate) fn problems(&self) -> &CrateDefMapProblems {
-        &self.problems
-    }
-
     pub(crate) fn mk_module(&self, module_id: CrateModuleId) -> Module {
         Module { krate: self.krate, module_id }
     }
@@ -240,6 +223,15 @@ impl CrateDefMap {
         &self.extern_prelude
     }
 
+    pub(crate) fn add_diagnostics(
+        &self,
+        db: &impl DefDatabase,
+        module: CrateModuleId,
+        sink: &mut DiagnosticSink,
+    ) {
+        self.diagnostics.iter().for_each(|it| it.add_to(db, module, sink))
+    }
+
     pub(crate) fn resolve_macro(
         &self,
         macro_call_id: MacroCallId,
@@ -452,3 +444,48 @@ impl CrateDefMap {
         }
     }
 }
+
+mod diagnostics {
+    use relative_path::RelativePathBuf;
+    use ra_syntax::{AstPtr, AstNode, ast};
+
+    use crate::{
+        SourceItemId, DefDatabase,
+        nameres::CrateModuleId,
+        diagnostics::{DiagnosticSink, UnresolvedModule},
+};
+
+    #[derive(Debug, PartialEq, Eq)]
+    pub(super) enum DefDiagnostic {
+        UnresolvedModule {
+            module: CrateModuleId,
+            declaration: SourceItemId,
+            candidate: RelativePathBuf,
+        },
+    }
+
+    impl DefDiagnostic {
+        pub(super) fn add_to(
+            &self,
+            db: &impl DefDatabase,
+            target_module: CrateModuleId,
+            sink: &mut DiagnosticSink,
+        ) {
+            match self {
+                DefDiagnostic::UnresolvedModule { module, declaration, candidate } => {
+                    if *module != target_module {
+                        return;
+                    }
+                    let syntax = db.file_item(*declaration);
+                    let decl = ast::Module::cast(&syntax).unwrap();
+                    sink.push(UnresolvedModule {
+                        file: declaration.file_id,
+                        decl: AstPtr::new(&decl),
+                        candidate: candidate.clone(),
+                    })
+                }
+            }
+        }
+    }
+
+}

crates/ra_hir/src/nameres/collector.rs

@@ -6,14 +6,17 @@ use ra_db::FileId;
 
 use crate::{
     Function, Module, Struct, Enum, Const, Static, Trait, TypeAlias,
-    DefDatabase, HirFileId, Name, Path, Problem, Crate,
+    DefDatabase, HirFileId, Name, Path, Crate,
     KnownName,
-    nameres::{Resolution, PerNs, ModuleDef, ReachedFixedPoint, ResolveMode, raw},
+    nameres::{
+        Resolution, PerNs, ModuleDef, ReachedFixedPoint, ResolveMode,
+        CrateDefMap, CrateModuleId, ModuleData, CrateMacroId,
+        diagnostics::DefDiagnostic,
+        raw,
+    },
     ids::{AstItemDef, LocationCtx, MacroCallLoc, SourceItemId, MacroCallId},
 };
 
-use super::{CrateDefMap, CrateModuleId, ModuleData, CrateMacroId};
-
 pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
     // populate external prelude
     for dep in def_map.krate.dependencies(db) {
@@ -405,25 +408,27 @@ where
             raw::ModuleData::Declaration { name, source_item_id } => {
                 let source_item_id = source_item_id.with_file_id(self.file_id);
                 let is_root = self.def_collector.def_map.modules[self.module_id].parent.is_none();
-                let (file_ids, problem) =
-                    resolve_submodule(self.def_collector.db, self.file_id, name, is_root);
-
-                if let Some(problem) = problem {
-                    self.def_collector.def_map.problems.add(source_item_id, problem)
-                }
-
-                if let Some(&file_id) = file_ids.first() {
-                    let module_id =
-                        self.push_child_module(name.clone(), source_item_id, Some(file_id));
-                    let raw_items = self.def_collector.db.raw_items(file_id);
-                    ModCollector {
-                        def_collector: &mut *self.def_collector,
-                        module_id,
-                        file_id: file_id.into(),
-                        raw_items: &raw_items,
+                match resolve_submodule(self.def_collector.db, self.file_id, name, is_root) {
+                    Ok(file_id) => {
+                        let module_id =
+                            self.push_child_module(name.clone(), source_item_id, Some(file_id));
+                        let raw_items = self.def_collector.db.raw_items(file_id);
+                        ModCollector {
+                            def_collector: &mut *self.def_collector,
+                            module_id,
+                            file_id: file_id.into(),
+                            raw_items: &raw_items,
+                        }
+                        .collect(raw_items.items())
                     }
-                    .collect(raw_items.items())
-                }
+                    Err(candidate) => self.def_collector.def_map.diagnostics.push(
+                        DefDiagnostic::UnresolvedModule {
+                            module: self.module_id,
+                            declaration: source_item_id,
+                            candidate,
+                        },
+                    ),
+                };
             }
         }
     }
@@ -524,7 +529,7 @@ fn resolve_submodule(
     file_id: HirFileId,
     name: &Name,
     is_root: bool,
-) -> (Vec<FileId>, Option<Problem>) {
+) -> Result<FileId, RelativePathBuf> {
     // FIXME: handle submodules of inline modules properly
     let file_id = file_id.original_file(db);
     let source_root_id = db.file_source_root(file_id);
@@ -545,17 +550,10 @@ fn resolve_submodule(
         candidates.push(file_dir_mod.clone());
     };
     let sr = db.source_root(source_root_id);
-    let points_to = candidates
-        .into_iter()
-        .filter_map(|path| sr.files.get(&path))
-        .map(|&it| it)
-        .collect::<Vec<_>>();
-    let problem = if points_to.is_empty() {
-        Some(Problem::UnresolvedModule {
-            candidate: if is_dir_owner { file_mod } else { file_dir_mod },
-        })
-    } else {
-        None
-    };
-    (points_to, problem)
+    let mut points_to = candidates.into_iter().filter_map(|path| sr.files.get(&path)).map(|&it| it);
+    // FIXME: handle ambiguity
+    match points_to.next() {
+        Some(file_id) => Ok(file_id),
+        None => Err(if is_dir_owner { file_mod } else { file_dir_mod }),
+    }
 }

crates/ra_hir/src/nameres/tests.rs

@@ -552,3 +552,22 @@ foo: v
 "###
     );
 }
+
+#[test]
+fn unresolved_module_diagnostics() {
+    let diagnostics = MockDatabase::with_files(
+        r"
+        //- /lib.rs
+        mod foo;
+        mod bar;
+        mod baz {}
+        //- /foo.rs
+        ",
+    )
+    .diagnostics();
+
+    assert_snapshot_matches!(diagnostics, @r###"
+"mod bar;": unresolved module
+"###
+    );
+}

crates/ra_hir/src/ty/infer.rs

@@ -36,7 +36,9 @@ use crate::{
     path::{GenericArgs, GenericArg},
     adt::VariantDef,
     resolve::{Resolver, Resolution},
-    nameres::Namespace
+    nameres::Namespace,
+    ty::infer::diagnostics::InferenceDiagnostic,
+    diagnostics::DiagnosticSink,
 };
 use super::{Ty, TypableDef, Substs, primitive, op, FnSig, ApplicationTy, TypeCtor};
 
@@ -96,6 +98,7 @@ pub struct InferenceResult {
     field_resolutions: FxHashMap<ExprId, StructField>,
     /// For each associated item record what it resolves to
     assoc_resolutions: FxHashMap<ExprOrPatId, ImplItem>,
+    diagnostics: Vec<InferenceDiagnostic>,
     pub(super) type_of_expr: ArenaMap<ExprId, Ty>,
     pub(super) type_of_pat: ArenaMap<PatId, Ty>,
 }
@@ -113,6 +116,14 @@ impl InferenceResult {
     pub fn assoc_resolutions_for_pat(&self, id: PatId) -> Option<ImplItem> {
         self.assoc_resolutions.get(&id.into()).map(|it| *it)
     }
+    pub(crate) fn add_diagnostics(
+        &self,
+        db: &impl HirDatabase,
+        owner: Function,
+        sink: &mut DiagnosticSink,
+    ) {
+        self.diagnostics.iter().for_each(|it| it.add_to(db, owner, sink))
+    }
 }
 
 impl Index<ExprId> for InferenceResult {
@@ -143,6 +154,7 @@ struct InferenceContext<'a, D: HirDatabase> {
     assoc_resolutions: FxHashMap<ExprOrPatId, ImplItem>,
     type_of_expr: ArenaMap<ExprId, Ty>,
     type_of_pat: ArenaMap<PatId, Ty>,
+    diagnostics: Vec<InferenceDiagnostic>,
     /// The return type of the function being inferred.
     return_ty: Ty,
 }
@@ -155,6 +167,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             assoc_resolutions: FxHashMap::default(),
             type_of_expr: ArenaMap::default(),
             type_of_pat: ArenaMap::default(),
+            diagnostics: Vec::default(),
             var_unification_table: InPlaceUnificationTable::new(),
             return_ty: Ty::Unknown, // set in collect_fn_signature
             db,
@@ -181,6 +194,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             assoc_resolutions: self.assoc_resolutions,
             type_of_expr: expr_types,
             type_of_pat: pat_types,
+            diagnostics: self.diagnostics,
         }
     }
 
@@ -915,9 +929,18 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Expr::StructLit { path, fields, spread } => {
                 let (ty, def_id) = self.resolve_variant(path.as_ref());
                 let substs = ty.substs().unwrap_or_else(Substs::empty);
-                for field in fields {
+                for (field_idx, field) in fields.into_iter().enumerate() {
                     let field_ty = def_id
-                        .and_then(|it| it.field(self.db, &field.name))
+                        .and_then(|it| match it.field(self.db, &field.name) {
+                            Some(field) => Some(field),
+                            None => {
+                                self.diagnostics.push(InferenceDiagnostic::NoSuchField {
+                                    expr: tgt_expr,
+                                    field: field_idx,
+                                });
+                                None
+                            }
+                        })
                         .map_or(Ty::Unknown, |field| field.ty(self.db))
                         .subst(&substs);
                     self.infer_expr(field.expr, &Expectation::has_type(field_ty));
@@ -1244,3 +1267,29 @@ impl Expectation {
         Expectation { ty: Ty::Unknown }
     }
 }
+
+mod diagnostics {
+    use crate::{expr::ExprId, diagnostics::{DiagnosticSink, NoSuchField}, HirDatabase, Function};
+
+    #[derive(Debug, PartialEq, Eq, Clone)]
+    pub(super) enum InferenceDiagnostic {
+        NoSuchField { expr: ExprId, field: usize },
+    }
+
+    impl InferenceDiagnostic {
+        pub(super) fn add_to(
+            &self,
+            db: &impl HirDatabase,
+            owner: Function,
+            sink: &mut DiagnosticSink,
+        ) {
+            match self {
+                InferenceDiagnostic::NoSuchField { expr, field } => {
+                    let (file, _) = owner.source(db);
+                    let field = owner.body_source_map(db).field_syntax(*expr, *field);
+                    sink.push(NoSuchField { file, field })
+                }
+            }
+        }
+    }
+}

crates/ra_hir/src/ty/tests.rs

@@ -2319,3 +2319,27 @@ fn typing_whitespace_inside_a_function_should_not_invalidate_types() {
         assert!(!format!("{:?}", events).contains("infer"), "{:#?}", events)
     }
 }
+
+#[test]
+fn no_such_field_diagnostics() {
+    let diagnostics = MockDatabase::with_files(
+        r"
+        //- /lib.rs
+        struct S { foo: i32, bar: () }
+        impl S {
+            fn new() -> S {
+                S {
+                    foo: 92,
+                    baz: 62,
+                }
+            }
+        }
+        ",
+    )
+    .diagnostics();
+
+    assert_snapshot_matches!(diagnostics, @r###"
+"baz: 62": no such field
+"###
+    );
+}

crates/ra_ide_api/src/diagnostics.rs

@@ -1,10 +1,11 @@
+use std::cell::RefCell;
+
 use itertools::Itertools;
-use hir::{Problem, source_binder};
+use hir::{source_binder, diagnostics::{Diagnostic as _, DiagnosticSink}};
 use ra_db::SourceDatabase;
 use ra_syntax::{
     Location, SourceFile, SyntaxKind, TextRange, SyntaxNode,
     ast::{self, AstNode},
-
 };
 use ra_text_edit::{TextEdit, TextEditBuilder};
 
@@ -26,11 +27,31 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
         check_unnecessary_braces_in_use_statement(&mut res, file_id, node);
         check_struct_shorthand_initialization(&mut res, file_id, node);
     }
-
+    let res = RefCell::new(res);
+    let mut sink = DiagnosticSink::new(|d| {
+        res.borrow_mut().push(Diagnostic {
+            message: d.message(),
+            range: d.highlight_range(),
+            severity: Severity::Error,
+            fix: None,
+        })
+    })
+    .on::<hir::diagnostics::UnresolvedModule, _>(|d| {
+        let source_root = db.file_source_root(d.file().original_file(db));
+        let create_file = FileSystemEdit::CreateFile { source_root, path: d.candidate.clone() };
+        let fix = SourceChange::file_system_edit("create module", create_file);
+        res.borrow_mut().push(Diagnostic {
+            range: d.highlight_range(),
+            message: d.message(),
+            severity: Severity::Error,
+            fix: Some(fix),
+        })
+    });
     if let Some(m) = source_binder::module_from_file_id(db, file_id) {
-        check_module(&mut res, db, file_id, m);
+        m.diagnostics(db, &mut sink);
     };
-    res
+    drop(sink);
+    res.into_inner()
 }
 
 fn syntax_errors(acc: &mut Vec<Diagnostic>, source_file: &SourceFile) {
@@ -128,34 +149,12 @@ fn check_struct_shorthand_initialization(
     Some(())
 }
 
-fn check_module(
-    acc: &mut Vec<Diagnostic>,
-    db: &RootDatabase,
-    file_id: FileId,
-    module: hir::Module,
-) {
-    let source_root = db.file_source_root(file_id);
-    for (name_node, problem) in module.problems(db) {
-        let diag = match problem {
-            Problem::UnresolvedModule { candidate } => {
-                let create_file =
-                    FileSystemEdit::CreateFile { source_root, path: candidate.clone() };
-                let fix = SourceChange::file_system_edit("create module", create_file);
-                Diagnostic {
-                    range: name_node.range(),
-                    message: "unresolved module".to_string(),
-                    severity: Severity::Error,
-                    fix: Some(fix),
-                }
-            }
-        };
-        acc.push(diag)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use test_utils::assert_eq_text;
+    use insta::assert_debug_snapshot_matches;
+
+    use crate::mock_analysis::single_file;
 
     use super::*;
 
@@ -184,6 +183,34 @@ mod tests {
         assert_eq_text!(after, &actual);
     }
 
+    #[test]
+    fn test_unresolved_module_diagnostic() {
+        let (analysis, file_id) = single_file("mod foo;");
+        let diagnostics = analysis.diagnostics(file_id).unwrap();
+        assert_debug_snapshot_matches!(diagnostics, @r####"[
+    Diagnostic {
+        message: "unresolved module",
+        range: [0; 8),
+        fix: Some(
+            SourceChange {
+                label: "create module",
+                source_file_edits: [],
+                file_system_edits: [
+                    CreateFile {
+                        source_root: SourceRootId(
+                            0
+                        ),
+                        path: "foo.rs"
+                    }
+                ],
+                cursor_position: None
+            }
+        ),
+        severity: Error
+    }
+]"####);
+    }
+
     #[test]
     fn test_check_unnecessary_braces_in_use_statement() {
         check_not_applicable(

crates/ra_ide_api/tests/test/main.rs

@@ -1,4 +1,3 @@
-use insta::assert_debug_snapshot_matches;
 use ra_ide_api::{
     mock_analysis::{single_file, single_file_with_position, single_file_with_range, MockAnalysis},
     AnalysisChange, CrateGraph, Edition::Edition2018, Query, NavigationTarget,
@@ -6,21 +5,6 @@ use ra_ide_api::{
 };
 use ra_syntax::SmolStr;
 
-#[test]
-fn test_unresolved_module_diagnostic() {
-    let (analysis, file_id) = single_file("mod foo;");
-    let diagnostics = analysis.diagnostics(file_id).unwrap();
-    assert_debug_snapshot_matches!("unresolved_module_diagnostic", &diagnostics);
-}
-
-// FIXME: move this test to hir
-#[test]
-fn test_unresolved_module_diagnostic_no_diag_for_inline_mode() {
-    let (analysis, file_id) = single_file("mod foo {}");
-    let diagnostics = analysis.diagnostics(file_id).unwrap();
-    assert!(diagnostics.is_empty());
-}
-
 #[test]
 fn test_resolve_crate_root() {
     let mock = MockAnalysis::with_files(

crates/ra_ide_api/tests/test/snapshots/test__unresolved_module_diagnostic.snap

@@ -1,28 +0,0 @@
----
-created: "2019-01-22T14:45:01.486985900+00:00"
-creator: insta@0.4.0
-expression: "&diagnostics"
-source: "crates\\ra_ide_api\\tests\\test\\main.rs"
----
-[
-    Diagnostic {
-        message: "unresolved module",
-        range: [0; 8),
-        fix: Some(
-            SourceChange {
-                label: "create module",
-                source_file_edits: [],
-                file_system_edits: [
-                    CreateFile {
-                        source_root: SourceRootId(
-                            0
-                        ),
-                        path: "foo.rs"
-                    }
-                ],
-                cursor_position: None
-            }
-        ),
-        severity: Error
-    }
-]

crates/ra_syntax/src/ptr.rs

@@ -64,6 +64,12 @@ impl<N: AstNode> AstPtr<N> {
     }
 }
 
+impl<N: AstNode> From<AstPtr<N>> for SyntaxNodePtr {
+    fn from(ptr: AstPtr<N>) -> SyntaxNodePtr {
+        ptr.raw
+    }
+}
+
 #[test]
 fn test_local_syntax_ptr() {
     use crate::{ast, AstNode};