5 files changed, 149 insertions, 24 deletions

diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 27cdabea0..0007d7fa8 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -4,6 +4,7 @@ use std::{iter, sync::Arc};
 use arrayvec::ArrayVec;
 use either::Either;
 use hir_def::{
+    adt::ReprKind,
     adt::StructKind,
     adt::VariantData,
     builtin_type::BuiltinType,
@@ -83,9 +84,9 @@ impl Crate {
             .collect()
     }
 
-    pub fn root_module(self, db: &dyn HirDatabase) -> Option<Module> {
+    pub fn root_module(self, db: &dyn HirDatabase) -> Module {
         let module_id = db.crate_def_map(self.id).root;
-        Some(Module::new(self, module_id))
+        Module::new(self, module_id)
     }
 
     pub fn root_file(self, db: &dyn HirDatabase) -> FileId {
@@ -431,6 +432,10 @@ impl Struct {
         Type::from_def(db, self.id.lookup(db.upcast()).container.module(db.upcast()).krate, self.id)
     }
 
+    pub fn repr(self, db: &dyn HirDatabase) -> Option<ReprKind> {
+        db.struct_data(self.id).repr.clone()
+    }
+
     fn variant_data(self, db: &dyn HirDatabase) -> Arc<VariantData> {
         db.struct_data(self.id).variant_data.clone()
     }
@@ -1253,6 +1258,19 @@ impl Type {
         )
     }
 
+    pub fn is_packed(&self, db: &dyn HirDatabase) -> bool {
+        let adt_id = match self.ty.value {
+            Ty::Apply(ApplicationTy { ctor: TypeCtor::Adt(adt_id), .. }) => adt_id,
+            _ => return false,
+        };
+
+        let adt = adt_id.into();
+        match adt {
+            Adt::Struct(s) => matches!(s.repr(db), Some(ReprKind::Packed)),
+            _ => false,
+        }
+    }
+
     pub fn is_raw_ptr(&self) -> bool {
         matches!(&self.ty.value, Ty::Apply(ApplicationTy { ctor: TypeCtor::RawPtr(..), .. }))
     }
diff --git a/crates/ra_hir/src/diagnostics.rs b/crates/ra_hir/src/diagnostics.rs
index 266b513dc..363164b9b 100644
--- a/crates/ra_hir/src/diagnostics.rs
+++ b/crates/ra_hir/src/diagnostics.rs
@@ -1,8 +1,6 @@
 //! FIXME: write short doc here
 pub use hir_def::diagnostics::UnresolvedModule;
-pub use hir_expand::diagnostics::{
-    AstDiagnostic, Diagnostic, DiagnosticSink, DiagnosticSinkBuilder,
-};
+pub use hir_expand::diagnostics::{Diagnostic, DiagnosticSink, DiagnosticSinkBuilder};
 pub use hir_ty::diagnostics::{
     MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkInTailExpr, NoSuchField,
 };
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 31f3241c9..34b02c536 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -49,7 +49,7 @@ pub use hir_def::{
     docs::Documentation,
     nameres::ModuleSource,
     path::{ModPath, Path, PathKind},
-    type_ref::Mutability,
+    type_ref::{Mutability, TypeRef},
 };
 pub use hir_expand::{
     hygiene::Hygiene, name::Name, HirFileId, InFile, MacroCallId, MacroCallLoc,
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 307b336f2..36b688ccb 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -8,7 +8,7 @@ use hir_def::{
     resolver::{self, HasResolver, Resolver},
     AsMacroCall, FunctionId, TraitId, VariantId,
 };
-use hir_expand::{diagnostics::AstDiagnostic, hygiene::Hygiene, ExpansionInfo};
+use hir_expand::{hygiene::Hygiene, name::AsName, ExpansionInfo};
 use hir_ty::associated_type_shorthand_candidates;
 use itertools::Itertools;
 use ra_db::{FileId, FileRange};
@@ -24,8 +24,9 @@ use crate::{
     diagnostics::Diagnostic,
     semantics::source_to_def::{ChildContainer, SourceToDefCache, SourceToDefCtx},
     source_analyzer::{resolve_hir_path, resolve_hir_path_qualifier, SourceAnalyzer},
-    AssocItem, Callable, Field, Function, HirFileId, ImplDef, InFile, Local, MacroDef, Module,
-    ModuleDef, Name, Origin, Path, ScopeDef, Trait, Type, TypeAlias, TypeParam, VariantDef,
+    AssocItem, Callable, Crate, Field, Function, HirFileId, ImplDef, InFile, Local, MacroDef,
+    Module, ModuleDef, Name, Origin, Path, ScopeDef, Trait, Type, TypeAlias, TypeParam, TypeRef,
+    VariantDef,
 };
 use resolver::TypeNs;
 
@@ -109,13 +110,6 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.parse(file_id)
     }
 
-    pub fn ast<T: AstDiagnostic + Diagnostic>(&self, d: &T) -> <T as AstDiagnostic>::AST {
-        let file_id = d.source().file_id;
-        let root = self.db.parse_or_expand(file_id).unwrap();
-        self.imp.cache(root, file_id);
-        d.ast(self.db.upcast())
-    }
-
     pub fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
         self.imp.expand(macro_call)
     }
@@ -145,8 +139,8 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.original_range(node)
     }
 
-    pub fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
-        self.imp.diagnostics_range(diagnostics)
+    pub fn diagnostics_display_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+        self.imp.diagnostics_display_range(diagnostics)
     }
 
     pub fn ancestors_with_macros(&self, node: SyntaxNode) -> impl Iterator<Item = SyntaxNode> + '_ {
@@ -228,6 +222,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.resolve_path(path)
     }
 
+    pub fn resolve_extern_crate(&self, extern_crate: &ast::ExternCrate) -> Option<Crate> {
+        self.imp.resolve_extern_crate(extern_crate)
+    }
+
     pub fn resolve_variant(&self, record_lit: ast::RecordExpr) -> Option<VariantDef> {
         self.imp.resolve_variant(record_lit).map(VariantDef::from)
     }
@@ -275,6 +273,18 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
     pub fn assert_contains_node(&self, node: &SyntaxNode) {
         self.imp.assert_contains_node(node)
     }
+
+    pub fn is_unsafe_method_call(&self, method_call_expr: ast::MethodCallExpr) -> bool {
+        self.imp.is_unsafe_method_call(method_call_expr)
+    }
+
+    pub fn is_unsafe_ref_expr(&self, ref_expr: &ast::RefExpr) -> bool {
+        self.imp.is_unsafe_ref_expr(ref_expr)
+    }
+
+    pub fn is_unsafe_ident_pat(&self, ident_pat: &ast::IdentPat) -> bool {
+        self.imp.is_unsafe_ident_pat(ident_pat)
+    }
 }
 
 impl<'db> SemanticsImpl<'db> {
@@ -372,10 +382,11 @@ impl<'db> SemanticsImpl<'db> {
         original_range(self.db, node.as_ref())
     }
 
-    fn diagnostics_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
-        let src = diagnostics.source();
+    fn diagnostics_display_range(&self, diagnostics: &dyn Diagnostic) -> FileRange {
+        let src = diagnostics.display_source();
         let root = self.db.parse_or_expand(src.file_id).unwrap();
         let node = src.value.to_node(&root);
+        self.cache(root, src.file_id);
         original_range(self.db, src.with_value(&node))
     }
 
@@ -443,6 +454,17 @@ impl<'db> SemanticsImpl<'db> {
         self.analyze(path.syntax()).resolve_path(self.db, path)
     }
 
+    fn resolve_extern_crate(&self, extern_crate: &ast::ExternCrate) -> Option<Crate> {
+        let krate = self.scope(extern_crate.syntax()).krate()?;
+        krate.dependencies(self.db).into_iter().find_map(|dep| {
+            if dep.name == extern_crate.name_ref()?.as_name() {
+                Some(dep.krate)
+            } else {
+                None
+            }
+        })
+    }
+
     fn resolve_variant(&self, record_lit: ast::RecordExpr) -> Option<VariantId> {
         self.analyze(record_lit.syntax()).resolve_variant(self.db, record_lit)
     }
@@ -559,6 +581,90 @@ impl<'db> SemanticsImpl<'db> {
         });
         InFile::new(file_id, node)
     }
+
+    pub fn is_unsafe_method_call(&self, method_call_expr: ast::MethodCallExpr) -> bool {
+        method_call_expr
+            .expr()
+            .and_then(|expr| {
+                let field_expr = if let ast::Expr::FieldExpr(field_expr) = expr {
+                    field_expr
+                } else {
+                    return None;
+                };
+                let ty = self.type_of_expr(&field_expr.expr()?)?;
+                if !ty.is_packed(self.db) {
+                    return None;
+                }
+
+                let func = self.resolve_method_call(&method_call_expr).map(Function::from)?;
+                let is_unsafe = func.has_self_param(self.db)
+                    && matches!(func.params(self.db).first(), Some(TypeRef::Reference(..)));
+                Some(is_unsafe)
+            })
+            .unwrap_or(false)
+    }
+
+    pub fn is_unsafe_ref_expr(&self, ref_expr: &ast::RefExpr) -> bool {
+        ref_expr
+            .expr()
+            .and_then(|expr| {
+                let field_expr = match expr {
+                    ast::Expr::FieldExpr(field_expr) => field_expr,
+                    _ => return None,
+                };
+                let expr = field_expr.expr()?;
+                self.type_of_expr(&expr)
+            })
+            // Binding a reference to a packed type is possibly unsafe.
+            .map(|ty| ty.is_packed(self.db))
+            .unwrap_or(false)
+
+        // FIXME This needs layout computation to be correct. It will highlight
+        // more than it should with the current implementation.
+    }
+
+    pub fn is_unsafe_ident_pat(&self, ident_pat: &ast::IdentPat) -> bool {
+        if !ident_pat.ref_token().is_some() {
+            return false;
+        }
+
+        ident_pat
+            .syntax()
+            .parent()
+            .and_then(|parent| {
+                // `IdentPat` can live under `RecordPat` directly under `RecordPatField` or
+                // `RecordPatFieldList`. `RecordPatField` also lives under `RecordPatFieldList`,
+                // so this tries to lookup the `IdentPat` anywhere along that structure to the
+                // `RecordPat` so we can get the containing type.
+                let record_pat = ast::RecordPatField::cast(parent.clone())
+                    .and_then(|record_pat| record_pat.syntax().parent())
+                    .or_else(|| Some(parent.clone()))
+                    .and_then(|parent| {
+                        ast::RecordPatFieldList::cast(parent)?
+                            .syntax()
+                            .parent()
+                            .and_then(ast::RecordPat::cast)
+                    });
+
+                // If this doesn't match a `RecordPat`, fallback to a `LetStmt` to see if
+                // this is initialized from a `FieldExpr`.
+                if let Some(record_pat) = record_pat {
+                    self.type_of_pat(&ast::Pat::RecordPat(record_pat))
+                } else if let Some(let_stmt) = ast::LetStmt::cast(parent) {
+                    let field_expr = match let_stmt.initializer()? {
+                        ast::Expr::FieldExpr(field_expr) => field_expr,
+                        _ => return None,
+                    };
+
+                    self.type_of_expr(&field_expr.expr()?)
+                } else {
+                    None
+                }
+            })
+            // Binding a reference to a packed type is possibly unsafe.
+            .map(|ty| ty.is_packed(self.db))
+            .unwrap_or(false)
+    }
 }
 
 pub trait ToDef: AstNode + Clone {
@@ -612,6 +718,10 @@ impl<'a> SemanticsScope<'a> {
         Some(Module { id: self.resolver.module()? })
     }
 
+    pub fn krate(&self) -> Option<Crate> {
+        Some(Crate { id: self.resolver.krate()? })
+    }
+
     /// Note: `FxHashSet<TraitId>` should be treated as an opaque type, passed into `Type
     // FIXME: rename to visible_traits to not repeat scope?
     pub fn traits_in_scope(&self) -> FxHashSet<TraitId> {
diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index d0cb62ef0..d3d62debf 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -265,8 +265,7 @@ impl SourceAnalyzer {
         }
 
         // This must be a normal source file rather than macro file.
-        let hir_path =
-            crate::Path::from_src(path.clone(), &Hygiene::new(db.upcast(), self.file_id))?;
+        let hir_path = Path::from_src(path.clone(), &Hygiene::new(db.upcast(), self.file_id))?;
 
         // Case where path is a qualifier of another path, e.g. foo::bar::Baz where we
         // trying to resolve foo::bar.
@@ -451,7 +450,7 @@ fn adjust(
 pub(crate) fn resolve_hir_path(
     db: &dyn HirDatabase,
     resolver: &Resolver,
-    path: &crate::Path,
+    path: &Path,
 ) -> Option<PathResolution> {
     let types =
         resolver.resolve_path_in_type_ns_fully(db.upcast(), path.mod_path()).map(|ty| match ty {
@@ -512,7 +511,7 @@ pub(crate) fn resolve_hir_path(
 pub(crate) fn resolve_hir_path_qualifier(
     db: &dyn HirDatabase,
     resolver: &Resolver,
-    path: &crate::Path,
+    path: &Path,
 ) -> Option<PathResolution> {
     let items = resolver
         .resolve_module_path_in_items(db.upcast(), path.mod_path())