15 files changed, 288 insertions, 120 deletions

diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index ab77d924a..786fad6e1 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -9,14 +9,14 @@ use std::{
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
-use hir_expand::{hygiene::Hygiene, name::AsName, AstId, InFile};
+use hir_expand::{hygiene::Hygiene, name::AsName, AstId, AttrId, InFile};
 use itertools::Itertools;
 use la_arena::ArenaMap;
 use mbe::ast_to_token_tree;
 use smallvec::{smallvec, SmallVec};
 use syntax::{
     ast::{self, AstNode, AttrsOwner},
-    match_ast, AstToken, SmolStr, SyntaxNode, TextRange, TextSize,
+    match_ast, AstPtr, AstToken, SmolStr, SyntaxNode, TextRange, TextSize,
 };
 use tt::Subtree;
 
@@ -98,13 +98,16 @@ impl RawAttrs {
     pub(crate) fn new(owner: &dyn ast::AttrsOwner, hygiene: &Hygiene) -> Self {
         let entries = collect_attrs(owner)
             .enumerate()
-            .flat_map(|(i, attr)| match attr {
-                Either::Left(attr) => Attr::from_src(attr, hygiene, i as u32),
-                Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
-                    index: i as u32,
-                    input: Some(AttrInput::Literal(SmolStr::new(doc))),
-                    path: Interned::new(ModPath::from(hir_expand::name!(doc))),
-                }),
+            .flat_map(|(i, attr)| {
+                let index = AttrId(i as u32);
+                match attr {
+                    Either::Left(attr) => Attr::from_src(attr, hygiene, index),
+                    Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
+                        id: index,
+                        input: Some(AttrInput::Literal(SmolStr::new(doc))),
+                        path: Interned::new(ModPath::from(hir_expand::name!(doc))),
+                    }),
+                }
             })
             .collect::<Arc<_>>();
 
@@ -161,7 +164,7 @@ impl RawAttrs {
                 let cfg = parts.next().unwrap();
                 let cfg = Subtree { delimiter: subtree.delimiter, token_trees: cfg.to_vec() };
                 let cfg = CfgExpr::parse(&cfg);
-                let index = attr.index;
+                let index = attr.id;
                 let attrs = parts.filter(|a| !a.is_empty()).filter_map(|attr| {
                     let tree = Subtree { delimiter: None, token_trees: attr.to_vec() };
                     let attr = ast::Attr::parse(&format!("#[{}]", tree)).ok()?;
@@ -215,12 +218,11 @@ impl Attrs {
         let mut res = ArenaMap::default();
 
         for (id, fld) in src.value.iter() {
-            let attrs = match fld {
-                Either::Left(_tuple) => Attrs::default(),
-                Either::Right(record) => {
-                    RawAttrs::from_attrs_owner(db, src.with_value(record)).filter(db, krate)
-                }
+            let owner: &dyn AttrsOwner = match fld {
+                Either::Left(tuple) => tuple,
+                Either::Right(record) => record,
             };
+            let attrs = RawAttrs::from_attrs_owner(db, src.with_value(owner)).filter(db, krate);
 
             res.insert(id, attrs);
         }
@@ -404,10 +406,14 @@ impl AttrsWithOwner {
                 return AttrSourceMap { attrs };
             }
             AttrDefId::FieldId(id) => {
-                id.parent.child_source(db).map(|source| match &source[id.local_id] {
-                    Either::Left(field) => ast::AttrsOwnerNode::new(field.clone()),
-                    Either::Right(field) => ast::AttrsOwnerNode::new(field.clone()),
-                })
+                let map = db.fields_attrs_source_map(id.parent);
+                let file_id = id.parent.file_id(db);
+                let root = db.parse_or_expand(file_id).unwrap();
+                let owner = match &map[id.local_id] {
+                    Either::Left(it) => ast::AttrsOwnerNode::new(it.to_node(&root)),
+                    Either::Right(it) => ast::AttrsOwnerNode::new(it.to_node(&root)),
+                };
+                InFile::new(file_id, owner)
             }
             AttrDefId::AdtId(adt) => match adt {
                 AdtId::StructId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
@@ -415,10 +421,12 @@ impl AttrsWithOwner {
                 AdtId::EnumId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
             },
             AttrDefId::FunctionId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
-            AttrDefId::EnumVariantId(id) => id
-                .parent
-                .child_source(db)
-                .map(|source| ast::AttrsOwnerNode::new(source[id.local_id].clone())),
+            AttrDefId::EnumVariantId(id) => {
+                let map = db.variants_attrs_source_map(id.parent);
+                let file_id = id.parent.lookup(db).id.file_id();
+                let root = db.parse_or_expand(file_id).unwrap();
+                InFile::new(file_id, ast::AttrsOwnerNode::new(map[id.local_id].to_node(&root)))
+            }
             AttrDefId::StaticId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
             AttrDefId::ConstId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
             AttrDefId::TraitId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
@@ -463,7 +471,7 @@ impl AttrsWithOwner {
     ) -> Option<(Documentation, DocsRangeMap)> {
         // FIXME: code duplication in `docs` above
         let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_ref()? {
-            AttrInput::Literal(s) => Some((s, attr.index)),
+            AttrInput::Literal(s) => Some((s, attr.id)),
             AttrInput::TokenTree(_) => None,
         });
         let indent = docs
@@ -555,8 +563,8 @@ impl AttrSourceMap {
     /// the attribute represented by `Attr`.
     pub fn source_of(&self, attr: &Attr) -> InFile<&Either<ast::Attr, ast::Comment>> {
         self.attrs
-            .get(attr.index as usize)
-            .unwrap_or_else(|| panic!("cannot find `Attr` at index {}", attr.index))
+            .get(attr.id.0 as usize)
+            .unwrap_or_else(|| panic!("cannot find `Attr` at index {:?}", attr.id))
             .as_ref()
     }
 }
@@ -567,7 +575,7 @@ pub struct DocsRangeMap {
     // (docstring-line-range, attr_index, attr-string-range)
     // a mapping from the text range of a line of the [`Documentation`] to the attribute index and
     // the original (untrimmed) syntax doc line
-    mapping: Vec<(TextRange, u32, TextRange)>,
+    mapping: Vec<(TextRange, AttrId, TextRange)>,
 }
 
 impl DocsRangeMap {
@@ -580,7 +588,7 @@ impl DocsRangeMap {
 
         let relative_range = range - line_docs_range.start();
 
-        let &InFile { file_id, value: ref source } = &self.source[idx as usize];
+        let &InFile { file_id, value: ref source } = &self.source[idx.0 as usize];
         match source {
             Either::Left(_) => None, // FIXME, figure out a nice way to handle doc attributes here
             // as well as for whats done in syntax highlight doc injection
@@ -601,7 +609,7 @@ impl DocsRangeMap {
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Attr {
-    index: u32,
+    pub(crate) id: AttrId,
     pub(crate) path: Interned<ModPath>,
     pub(crate) input: Option<AttrInput>,
 }
@@ -615,7 +623,7 @@ pub enum AttrInput {
 }
 
 impl Attr {
-    fn from_src(ast: ast::Attr, hygiene: &Hygiene, index: u32) -> Option<Attr> {
+    fn from_src(ast: ast::Attr, hygiene: &Hygiene, id: AttrId) -> Option<Attr> {
         let path = Interned::new(ModPath::from_src(ast.path()?, hygiene)?);
         let input = if let Some(ast::Expr::Literal(lit)) = ast.expr() {
             let value = match lit.kind() {
@@ -628,7 +636,7 @@ impl Attr {
         } else {
             None
         };
-        Some(Attr { index, path, input })
+        Some(Attr { id, path, input })
     }
 
     /// Parses this attribute as a `#[derive]`, returns an iterator that yields all contained paths
@@ -743,7 +751,38 @@ fn collect_attrs(
         .chain(inner_docs.into_iter().flatten())
         .map(|docs_text| (docs_text.syntax().text_range().start(), Either::Right(docs_text)));
     // sort here by syntax node offset because the source can have doc attributes and doc strings be interleaved
-    let attrs: Vec<_> = docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).collect();
+    docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).map(|(_, attr)| attr)
+}
+
+pub(crate) fn variants_attrs_source_map(
+    db: &dyn DefDatabase,
+    def: EnumId,
+) -> Arc<ArenaMap<LocalEnumVariantId, AstPtr<ast::Variant>>> {
+    let mut res = ArenaMap::default();
+    let child_source = def.child_source(db);
+
+    for (idx, variant) in child_source.value.iter() {
+        res.insert(idx, AstPtr::new(variant));
+    }
+
+    Arc::new(res)
+}
+
+pub(crate) fn fields_attrs_source_map(
+    db: &dyn DefDatabase,
+    def: VariantId,
+) -> Arc<ArenaMap<LocalFieldId, Either<AstPtr<ast::TupleField>, AstPtr<ast::RecordField>>>> {
+    let mut res = ArenaMap::default();
+    let child_source = def.child_source(db);
+
+    for (idx, variant) in child_source.value.iter() {
+        res.insert(
+            idx,
+            variant
+                .as_ref()
+                .either(|l| Either::Left(AstPtr::new(l)), |r| Either::Right(AstPtr::new(r))),
+        );
+    }
 
-    attrs.into_iter().map(|(_, attr)| attr)
+    Arc::new(res)
 }
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 63e89a1f4..ed07d6928 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -30,6 +30,7 @@ use crate::{
         LabelId, Literal, LogicOp, MatchArm, Ordering, Pat, PatId, RecordFieldPat, RecordLitField,
         Statement,
     },
+    intern::Interned,
     item_scope::BuiltinShadowMode,
     path::{GenericArgs, Path},
     type_ref::{Mutability, Rawness, TypeRef},
@@ -322,8 +323,10 @@ impl ExprCollector<'_> {
                     Vec::new()
                 };
                 let method_name = e.name_ref().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
-                let generic_args =
-                    e.generic_arg_list().and_then(|it| GenericArgs::from_ast(&self.ctx(), it));
+                let generic_args = e
+                    .generic_arg_list()
+                    .and_then(|it| GenericArgs::from_ast(&self.ctx(), it))
+                    .map(Box::new);
                 self.alloc_expr(
                     Expr::MethodCall { receiver, method_name, args, generic_args },
                     syntax_ptr,
@@ -385,7 +388,7 @@ impl ExprCollector<'_> {
                 self.alloc_expr(Expr::Yield { expr }, syntax_ptr)
             }
             ast::Expr::RecordExpr(e) => {
-                let path = e.path().and_then(|path| self.expander.parse_path(path));
+                let path = e.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                 let record_lit = if let Some(nfl) = e.record_expr_field_list() {
                     let fields = nfl
                         .fields()
@@ -430,7 +433,7 @@ impl ExprCollector<'_> {
             }
             ast::Expr::CastExpr(e) => {
                 let expr = self.collect_expr_opt(e.expr());
-                let type_ref = TypeRef::from_ast_opt(&self.ctx(), e.ty());
+                let type_ref = Interned::new(TypeRef::from_ast_opt(&self.ctx(), e.ty()));
                 self.alloc_expr(Expr::Cast { expr, type_ref }, syntax_ptr)
             }
             ast::Expr::RefExpr(e) => {
@@ -464,13 +467,16 @@ impl ExprCollector<'_> {
                 if let Some(pl) = e.param_list() {
                     for param in pl.params() {
                         let pat = self.collect_pat_opt(param.pat());
-                        let type_ref = param.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
+                        let type_ref =
+                            param.ty().map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
                         args.push(pat);
                         arg_types.push(type_ref);
                     }
                 }
-                let ret_type =
-                    e.ret_type().and_then(|r| r.ty()).map(|it| TypeRef::from_ast(&self.ctx(), it));
+                let ret_type = e
+                    .ret_type()
+                    .and_then(|r| r.ty())
+                    .map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
                 let body = self.collect_expr_opt(e.body());
                 self.alloc_expr(Expr::Lambda { args, arg_types, ret_type, body }, syntax_ptr)
             }
@@ -525,8 +531,9 @@ impl ExprCollector<'_> {
                 }
             }
             ast::Expr::MacroCall(e) => {
+                let macro_ptr = AstPtr::new(&e);
                 let mut ids = vec![];
-                self.collect_macro_call(e, syntax_ptr.clone(), true, |this, expansion| {
+                self.collect_macro_call(e, macro_ptr, true, |this, expansion| {
                     ids.push(match expansion {
                         Some(it) => this.collect_expr(it),
                         None => this.alloc_expr(Expr::Missing, syntax_ptr.clone()),
@@ -549,7 +556,7 @@ impl ExprCollector<'_> {
     fn collect_macro_call<F: FnMut(&mut Self, Option<T>), T: ast::AstNode>(
         &mut self,
         e: ast::MacroCall,
-        syntax_ptr: AstPtr<ast::Expr>,
+        syntax_ptr: AstPtr<ast::MacroCall>,
         is_error_recoverable: bool,
         mut collector: F,
     ) {
@@ -625,7 +632,8 @@ impl ExprCollector<'_> {
                     return;
                 }
                 let pat = self.collect_pat_opt(stmt.pat());
-                let type_ref = stmt.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
+                let type_ref =
+                    stmt.ty().map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
                 let initializer = stmt.initializer().map(|e| self.collect_expr(e));
                 self.statements_in_scope.push(Statement::Let { pat, type_ref, initializer });
             }
@@ -636,10 +644,14 @@ impl ExprCollector<'_> {
 
                 // Note that macro could be expended to multiple statements
                 if let Some(ast::Expr::MacroCall(m)) = stmt.expr() {
+                    let macro_ptr = AstPtr::new(&m);
                     let syntax_ptr = AstPtr::new(&stmt.expr().unwrap());
 
-                    self.collect_macro_call(m, syntax_ptr.clone(), false, |this, expansion| {
-                        match expansion {
+                    self.collect_macro_call(
+                        m,
+                        macro_ptr,
+                        false,
+                        |this, expansion| match expansion {
                             Some(expansion) => {
                                 let statements: ast::MacroStmts = expansion;
 
@@ -653,8 +665,8 @@ impl ExprCollector<'_> {
                                 let expr = this.alloc_expr(Expr::Missing, syntax_ptr.clone());
                                 this.statements_in_scope.push(Statement::Expr(expr));
                             }
-                        }
-                    });
+                        },
+                    );
                 } else {
                     let expr = self.collect_expr_opt(stmt.expr());
                     self.statements_in_scope.push(Statement::Expr(expr));
@@ -755,7 +767,7 @@ impl ExprCollector<'_> {
                 }
             }
             ast::Pat::TupleStructPat(p) => {
-                let path = p.path().and_then(|path| self.expander.parse_path(path));
+                let path = p.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                 let (args, ellipsis) = self.collect_tuple_pat(p.fields());
                 Pat::TupleStruct { path, args, ellipsis }
             }
@@ -765,7 +777,7 @@ impl ExprCollector<'_> {
                 Pat::Ref { pat, mutability }
             }
             ast::Pat::PathPat(p) => {
-                let path = p.path().and_then(|path| self.expander.parse_path(path));
+                let path = p.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                 path.map(Pat::Path).unwrap_or(Pat::Missing)
             }
             ast::Pat::OrPat(p) => {
@@ -779,7 +791,7 @@ impl ExprCollector<'_> {
             }
             ast::Pat::WildcardPat(_) => Pat::Wild,
             ast::Pat::RecordPat(p) => {
-                let path = p.path().and_then(|path| self.expander.parse_path(path));
+                let path = p.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                 let args: Vec<_> = p
                     .record_pat_field_list()
                     .expect("every struct should have a field list")
@@ -841,8 +853,23 @@ impl ExprCollector<'_> {
                     Pat::Missing
                 }
             }
+            ast::Pat::MacroPat(mac) => match mac.macro_call() {
+                Some(call) => {
+                    let macro_ptr = AstPtr::new(&call);
+                    let mut pat = None;
+                    self.collect_macro_call(call, macro_ptr, true, |this, expanded_pat| {
+                        pat = Some(this.collect_pat_opt(expanded_pat));
+                    });
+
+                    match pat {
+                        Some(pat) => return pat,
+                        None => Pat::Missing,
+                    }
+                }
+                None => Pat::Missing,
+            },
             // FIXME: implement
-            ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
+            ast::Pat::RangePat(_) => Pat::Missing,
         };
         let ptr = AstPtr::new(&pat);
         self.alloc_pat(pattern, Either::Left(ptr))
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index faa133297..c1d3e998f 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -143,7 +143,7 @@ fn f() {
   //^^^^^^^^^^^^^ could not convert tokens
 
     env!("OUT_DIR");
-  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "load out dirs from check" to fix
+  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
 
     compile_error!("compile_error works");
   //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ compile_error works
diff --git a/crates/hir_def/src/child_by_source.rs b/crates/hir_def/src/child_by_source.rs
index f40a7f80d..f2e809ca9 100644
--- a/crates/hir_def/src/child_by_source.rs
+++ b/crates/hir_def/src/child_by_source.rs
@@ -80,6 +80,10 @@ impl ChildBySource for ModuleId {
 impl ChildBySource for ItemScope {
     fn child_by_source_to(&self, db: &dyn DefDatabase, res: &mut DynMap) {
         self.declarations().for_each(|item| add_module_def(db, res, item));
+        self.unnamed_consts().for_each(|konst| {
+            let src = konst.lookup(db).source(db);
+            res[keys::CONST].insert(src, konst);
+        });
         self.impls().for_each(|imp| add_impl(db, res, imp));
 
         fn add_module_def(db: &dyn DefDatabase, map: &mut DynMap, item: ModuleDefId) {
diff --git a/crates/hir_def/src/db.rs b/crates/hir_def/src/db.rs
index 9b7a213a1..7eadc8e0d 100644
--- a/crates/hir_def/src/db.rs
+++ b/crates/hir_def/src/db.rs
@@ -2,9 +2,10 @@
 use std::sync::Arc;
 
 use base_db::{salsa, CrateId, SourceDatabase, Upcast};
+use either::Either;
 use hir_expand::{db::AstDatabase, HirFileId};
 use la_arena::ArenaMap;
-use syntax::SmolStr;
+use syntax::{ast, AstPtr, SmolStr};
 
 use crate::{
     adt::{EnumData, StructData},
@@ -122,6 +123,18 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
     #[salsa::invoke(Attrs::fields_attrs_query)]
     fn fields_attrs(&self, def: VariantId) -> Arc<ArenaMap<LocalFieldId, Attrs>>;
 
+    #[salsa::invoke(crate::attr::variants_attrs_source_map)]
+    fn variants_attrs_source_map(
+        &self,
+        def: EnumId,
+    ) -> Arc<ArenaMap<LocalEnumVariantId, AstPtr<ast::Variant>>>;
+
+    #[salsa::invoke(crate::attr::fields_attrs_source_map)]
+    fn fields_attrs_source_map(
+        &self,
+        def: VariantId,
+    ) -> Arc<ArenaMap<LocalFieldId, Either<AstPtr<ast::TupleField>, AstPtr<ast::RecordField>>>>;
+
     #[salsa::invoke(AttrsWithOwner::attrs_query)]
     fn attrs(&self, def: AttrDefId) -> AttrsWithOwner;
 
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index 6c7376fad..b4ad984bd 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -18,6 +18,7 @@ use syntax::ast::RangeOp;
 
 use crate::{
     builtin_type::{BuiltinFloat, BuiltinInt, BuiltinUint},
+    intern::Interned,
     path::{GenericArgs, Path},
     type_ref::{Mutability, Rawness, TypeRef},
     BlockId,
@@ -86,7 +87,7 @@ pub enum Expr {
         receiver: ExprId,
         method_name: Name,
         args: Vec<ExprId>,
-        generic_args: Option<GenericArgs>,
+        generic_args: Option<Box<GenericArgs>>,
     },
     Match {
         expr: ExprId,
@@ -106,7 +107,7 @@ pub enum Expr {
         expr: Option<ExprId>,
     },
     RecordLit {
-        path: Option<Path>,
+        path: Option<Box<Path>>,
         fields: Vec<RecordLitField>,
         spread: Option<ExprId>,
     },
@@ -131,7 +132,7 @@ pub enum Expr {
     },
     Cast {
         expr: ExprId,
-        type_ref: TypeRef,
+        type_ref: Interned<TypeRef>,
     },
     Ref {
         expr: ExprId,
@@ -161,8 +162,8 @@ pub enum Expr {
     },
     Lambda {
         args: Vec<PatId>,
-        arg_types: Vec<Option<TypeRef>>,
-        ret_type: Option<TypeRef>,
+        arg_types: Vec<Option<Interned<TypeRef>>>,
+        ret_type: Option<Interned<TypeRef>>,
         body: ExprId,
     },
     Tuple {
@@ -240,7 +241,7 @@ pub struct RecordLitField {
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum Statement {
-    Let { pat: PatId, type_ref: Option<TypeRef>, initializer: Option<ExprId> },
+    Let { pat: PatId, type_ref: Option<Interned<TypeRef>>, initializer: Option<ExprId> },
     Expr(ExprId),
 }
 
@@ -412,13 +413,13 @@ pub enum Pat {
     Wild,
     Tuple { args: Vec<PatId>, ellipsis: Option<usize> },
     Or(Vec<PatId>),
-    Record { path: Option<Path>, args: Vec<RecordFieldPat>, ellipsis: bool },
+    Record { path: Option<Box<Path>>, args: Vec<RecordFieldPat>, ellipsis: bool },
     Range { start: ExprId, end: ExprId },
     Slice { prefix: Vec<PatId>, slice: Option<PatId>, suffix: Vec<PatId> },
-    Path(Path),
+    Path(Box<Path>),
     Lit(ExprId),
     Bind { mode: BindingAnnotation, name: Name, subpat: Option<PatId> },
-    TupleStruct { path: Option<Path>, args: Vec<PatId>, ellipsis: Option<usize> },
+    TupleStruct { path: Option<Box<Path>>, args: Vec<PatId>, ellipsis: Option<usize> },
     Ref { pat: PatId, mutability: Mutability },
     Box { inner: PatId },
     ConstBlock(ExprId),
diff --git a/crates/hir_def/src/item_scope.rs b/crates/hir_def/src/item_scope.rs
index a8ee5eeac..9014468ea 100644
--- a/crates/hir_def/src/item_scope.rs
+++ b/crates/hir_def/src/item_scope.rs
@@ -11,7 +11,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::format_to;
 
 use crate::{
-    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ImplId,
+    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ConstId, ImplId,
     LocalModuleId, MacroDefId, ModuleDefId, ModuleId, TraitId,
 };
 
@@ -37,6 +37,7 @@ pub struct ItemScope {
 
     defs: Vec<ModuleDefId>,
     impls: Vec<ImplId>,
+    unnamed_consts: Vec<ConstId>,
     /// Traits imported via `use Trait as _;`.
     unnamed_trait_imports: FxHashMap<TraitId, Visibility>,
     /// Macros visible in current module in legacy textual scope
@@ -106,6 +107,10 @@ impl ItemScope {
             .map(|(_, v)| v)
     }
 
+    pub fn unnamed_consts(&self) -> impl Iterator<Item = ConstId> + '_ {
+        self.unnamed_consts.iter().copied()
+    }
+
     /// Iterate over all module scoped macros
     pub(crate) fn macros<'a>(&'a self) -> impl Iterator<Item = (&'a Name, MacroDefId)> + 'a {
         self.entries().filter_map(|(name, def)| def.take_macros().map(|macro_| (name, macro_)))
@@ -156,6 +161,10 @@ impl ItemScope {
         self.impls.push(imp)
     }
 
+    pub(crate) fn define_unnamed_const(&mut self, konst: ConstId) {
+        self.unnamed_consts.push(konst);
+    }
+
     pub(crate) fn define_legacy_macro(&mut self, name: Name, mac: MacroDefId) {
         self.legacy_macros.insert(name, mac);
     }
@@ -295,6 +304,7 @@ impl ItemScope {
             unresolved,
             defs,
             impls,
+            unnamed_consts,
             unnamed_trait_imports,
             legacy_macros,
         } = self;
@@ -304,6 +314,7 @@ impl ItemScope {
         unresolved.shrink_to_fit();
         defs.shrink_to_fit();
         impls.shrink_to_fit();
+        unnamed_consts.shrink_to_fit();
         unnamed_trait_imports.shrink_to_fit();
         legacy_macros.shrink_to_fit();
     }
diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 240662486..94e08f835 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -99,6 +99,11 @@ impl ItemTree {
                     // items.
                     ctx.lower_macro_stmts(stmts)
                 },
+                ast::Pat(_pat) => {
+                    // FIXME: This occurs because macros in pattern position are treated as inner
+                    // items and expanded during block DefMap computation
+                    return Default::default();
+                },
                 ast::Expr(e) => {
                     // Macros can expand to expressions. We return an empty item tree in this case, but
                     // still need to collect inner items.
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index c5629af24..45b099cf3 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -189,7 +189,7 @@ impl Ctx {
                                 block_stack.push(self.source_ast_id_map.ast_id(&block));
                             },
                             ast::Item(item) => {
-                                // FIXME: This triggers for macro calls in expression position
+                                // FIXME: This triggers for macro calls in expression/pattern/type position
                                 let mod_items = self.lower_mod_item(&item, true);
                                 let current_block = block_stack.last();
                                 if let (Some(mod_items), Some(block)) = (mod_items, current_block) {
diff --git a/crates/hir_def/src/lib.rs b/crates/hir_def/src/lib.rs
index be9a5e1a0..d69116d51 100644
--- a/crates/hir_def/src/lib.rs
+++ b/crates/hir_def/src/lib.rs
@@ -56,12 +56,13 @@ use std::{
     sync::Arc,
 };
 
+use adt::VariantData;
 use base_db::{impl_intern_key, salsa, CrateId};
 use hir_expand::{
     ast_id_map::FileAstId,
     eager::{expand_eager_macro, ErrorEmitted, ErrorSink},
     hygiene::Hygiene,
-    AstId, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
+    AstId, AttrId, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
 };
 use la_arena::Idx;
 use nameres::DefMap;
@@ -442,6 +443,26 @@ pub enum VariantId {
 }
 impl_from!(EnumVariantId, StructId, UnionId for VariantId);
 
+impl VariantId {
+    pub fn variant_data(self, db: &dyn db::DefDatabase) -> Arc<VariantData> {
+        match self {
+            VariantId::StructId(it) => db.struct_data(it).variant_data.clone(),
+            VariantId::UnionId(it) => db.union_data(it).variant_data.clone(),
+            VariantId::EnumVariantId(it) => {
+                db.enum_data(it.parent).variants[it.local_id].variant_data.clone()
+            }
+        }
+    }
+
+    pub fn file_id(self, db: &dyn db::DefDatabase) -> HirFileId {
+        match self {
+            VariantId::EnumVariantId(it) => it.parent.lookup(db).id.file_id(),
+            VariantId::StructId(it) => it.lookup(db).id.file_id(),
+            VariantId::UnionId(it) => it.lookup(db).id.file_id(),
+        }
+    }
+}
+
 trait Intern {
     type ID;
     fn intern(self, db: &dyn db::DefDatabase) -> Self::ID;
@@ -669,13 +690,16 @@ fn macro_call_as_call_id(
         )
         .map(MacroCallId::from)
     } else {
-        Ok(def.as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike(call.ast_id)).into())
+        Ok(def
+            .as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike { ast_id: call.ast_id })
+            .into())
     };
     Ok(res)
 }
 
 fn derive_macro_as_call_id(
     item_attr: &AstIdWithPath<ast::Item>,
+    derive_attr: AttrId,
     db: &dyn db::DefDatabase,
     krate: CrateId,
     resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
@@ -686,7 +710,11 @@ fn derive_macro_as_call_id(
         .as_lazy_macro(
             db.upcast(),
             krate,
-            MacroCallKind::Derive(item_attr.ast_id, last_segment.to_string()),
+            MacroCallKind::Derive {
+                ast_id: item_attr.ast_id,
+                derive_name: last_segment.to_string(),
+                derive_attr,
+            },
         )
         .into();
     Ok(res)
diff --git a/crates/hir_def/src/nameres.rs b/crates/hir_def/src/nameres.rs
index 7dd68219f..9e181751c 100644
--- a/crates/hir_def/src/nameres.rs
+++ b/crates/hir_def/src/nameres.rs
@@ -613,12 +613,12 @@ mod diagnostics {
                 DiagnosticKind::UnresolvedProcMacro { ast } => {
                     let mut precise_location = None;
                     let (file, ast, name) = match ast {
-                        MacroCallKind::FnLike(ast) => {
-                            let node = ast.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
+                        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, name) => {
-                            let node = ast.to_node(db.upcast());
+                        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.
@@ -639,7 +639,7 @@ mod diagnostics {
                                     });
                                 for token in tokens {
                                     if token.kind() == SyntaxKind::IDENT
-                                        && token.text() == name.as_str()
+                                        && token.text() == derive_name.as_str()
                                     {
                                         precise_location = Some(token.text_range());
                                         break 'outer;
@@ -648,9 +648,9 @@ mod diagnostics {
                             }
 
                             (
-                                ast.file_id,
+                                ast_id.file_id,
                                 SyntaxNodePtr::from(AstPtr::new(&node)),
-                                Some(name.clone()),
+                                Some(derive_name.clone()),
                             )
                         }
                     };
@@ -669,13 +669,13 @@ mod diagnostics {
 
                 DiagnosticKind::MacroError { ast, message } => {
                     let (file, ast) = match ast {
-                        MacroCallKind::FnLike(ast) => {
-                            let node = ast.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                        MacroCallKind::FnLike { ast_id, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
                         }
-                        MacroCallKind::Derive(ast, _) => {
-                            let node = ast.to_node(db.upcast());
-                            (ast.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() });
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index f42f92702..fb4ddff5e 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -13,7 +13,7 @@ use hir_expand::{
     builtin_macro::find_builtin_macro,
     name::{AsName, Name},
     proc_macro::ProcMacroExpander,
-    HirFileId, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
+    AttrId, HirFileId, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
 };
 use hir_expand::{InFile, MacroCallLoc};
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -216,7 +216,7 @@ struct MacroDirective {
 #[derive(Clone, Debug, Eq, PartialEq)]
 enum MacroDirectiveKind {
     FnLike { ast_id: AstIdWithPath<ast::MacroCall> },
-    Derive { ast_id: AstIdWithPath<ast::Item> },
+    Derive { ast_id: AstIdWithPath<ast::Item>, derive_attr: AttrId },
 }
 
 struct DefData<'a> {
@@ -478,7 +478,7 @@ impl DefCollector<'_> {
             self.def_map.edition,
         );
 
-        let res = self.def_map.resolve_name_in_extern_prelude(&extern_crate.name);
+        let res = self.def_map.resolve_name_in_extern_prelude(self.db, &extern_crate.name);
 
         if let Some(ModuleDefId::ModuleId(m)) = res.take_types() {
             cov_mark::hit!(macro_rules_from_other_crates_are_visible_with_macro_use);
@@ -534,6 +534,7 @@ impl DefCollector<'_> {
         log::debug!("resolving import: {:?} ({:?})", import, self.def_map.edition);
         if import.is_extern_crate {
             let res = self.def_map.resolve_name_in_extern_prelude(
+                self.db,
                 &import
                     .path
                     .as_ident()
@@ -831,12 +832,16 @@ impl DefCollector<'_> {
                         Err(UnresolvedMacro) | Ok(Err(_)) => {}
                     }
                 }
-                MacroDirectiveKind::Derive { ast_id } => {
-                    match derive_macro_as_call_id(ast_id, self.db, self.def_map.krate, |path| {
-                        self.resolve_derive_macro(directive.module_id, &path)
-                    }) {
+                MacroDirectiveKind::Derive { ast_id, derive_attr } => {
+                    match derive_macro_as_call_id(
+                        ast_id,
+                        *derive_attr,
+                        self.db,
+                        self.def_map.krate,
+                        |path| self.resolve_derive_macro(directive.module_id, &path),
+                    ) {
                         Ok(call_id) => {
-                            resolved.push((directive.module_id, call_id, 0));
+                            resolved.push((directive.module_id, call_id, directive.depth));
                             res = ReachedFixedPoint::No;
                             return false;
                         }
@@ -1163,19 +1168,27 @@ impl ModCollector<'_, '_> {
                 }
                 ModItem::Const(id) => {
                     let it = &self.item_tree[id];
-
-                    if let Some(name) = &it.name {
-                        def = Some(DefData {
-                            id: ConstLoc {
-                                container: module.into(),
-                                id: ItemTreeId::new(self.file_id, id),
-                            }
-                            .intern(self.def_collector.db)
-                            .into(),
-                            name,
-                            visibility: &self.item_tree[it.visibility],
-                            has_constructor: false,
-                        });
+                    let const_id = ConstLoc {
+                        container: module.into(),
+                        id: ItemTreeId::new(self.file_id, id),
+                    }
+                    .intern(self.def_collector.db);
+
+                    match &it.name {
+                        Some(name) => {
+                            def = Some(DefData {
+                                id: const_id.into(),
+                                name,
+                                visibility: &self.item_tree[it.visibility],
+                                has_constructor: false,
+                            });
+                        }
+                        None => {
+                            // const _: T = ...;
+                            self.def_collector.def_map.modules[self.module_id]
+                                .scope
+                                .define_unnamed_const(const_id);
+                        }
                     }
                 }
                 ModItem::Static(id) => {
@@ -1360,7 +1373,7 @@ impl ModCollector<'_, '_> {
                         self.def_collector.unexpanded_macros.push(MacroDirective {
                             module_id: self.module_id,
                             depth: self.macro_depth + 1,
-                            kind: MacroDirectiveKind::Derive { ast_id },
+                            kind: MacroDirectiveKind::Derive { ast_id, derive_attr: derive.id },
                         });
                     }
                 }
@@ -1512,7 +1525,7 @@ impl ModCollector<'_, '_> {
                 // Built-in macro failed eager expansion.
                 self.def_collector.def_map.diagnostics.push(DefDiagnostic::macro_error(
                     self.module_id,
-                    MacroCallKind::FnLike(ast_id.ast_id),
+                    MacroCallKind::FnLike { ast_id: ast_id.ast_id },
                     error.unwrap().to_string(),
                 ));
                 return;
diff --git a/crates/hir_def/src/nameres/path_resolution.rs b/crates/hir_def/src/nameres/path_resolution.rs
index 60471937c..ccc9f22eb 100644
--- a/crates/hir_def/src/nameres/path_resolution.rs
+++ b/crates/hir_def/src/nameres/path_resolution.rs
@@ -60,12 +60,26 @@ impl ResolvePathResult {
 }
 
 impl DefMap {
-    pub(super) fn resolve_name_in_extern_prelude(&self, name: &Name) -> PerNs {
+    pub(super) fn resolve_name_in_extern_prelude(
+        &self,
+        db: &dyn DefDatabase,
+        name: &Name,
+    ) -> PerNs {
         if name == &name!(self) {
             cov_mark::hit!(extern_crate_self_as);
             return PerNs::types(self.module_id(self.root).into(), Visibility::Public);
         }
-        self.extern_prelude
+
+        let arc;
+        let root = match self.block {
+            Some(_) => {
+                arc = self.crate_root(db).def_map(db);
+                &*arc
+            }
+            None => self,
+        };
+
+        root.extern_prelude
             .get(name)
             .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public))
     }
@@ -191,7 +205,7 @@ impl DefMap {
                     None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
                 };
                 log::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
-                self.resolve_name_in_crate_root_or_extern_prelude(&segment)
+                self.resolve_name_in_crate_root_or_extern_prelude(db, &segment)
             }
             PathKind::Plain => {
                 let (_, segment) = match segments.next() {
@@ -384,24 +398,31 @@ impl DefMap {
                 }
             }
         };
-        // Give precedence to names in outer `DefMap`s over the extern prelude; only check prelude
-        // from the crate DefMap.
-        let from_extern_prelude = match self.block {
-            Some(_) => PerNs::none(),
-            None => self
-                .extern_prelude
-                .get(name)
-                .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public)),
-        };
+        let from_extern_prelude = self
+            .extern_prelude
+            .get(name)
+            .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public));
 
         let from_prelude = self.resolve_in_prelude(db, name);
 
         from_legacy_macro.or(from_scope_or_builtin).or(from_extern_prelude).or(from_prelude)
     }
 
-    fn resolve_name_in_crate_root_or_extern_prelude(&self, name: &Name) -> PerNs {
-        let from_crate_root = self[self.root].scope.get(name);
-        let from_extern_prelude = self.resolve_name_in_extern_prelude(name);
+    fn resolve_name_in_crate_root_or_extern_prelude(
+        &self,
+        db: &dyn DefDatabase,
+        name: &Name,
+    ) -> PerNs {
+        let arc;
+        let crate_def_map = match self.block {
+            Some(_) => {
+                arc = self.crate_root(db).def_map(db);
+                &arc
+            }
+            None => self,
+        };
+        let from_crate_root = crate_def_map[crate_def_map.root].scope.get(name);
+        let from_extern_prelude = self.resolve_name_in_extern_prelude(db, name);
 
         from_crate_root.or(from_extern_prelude)
     }
diff --git a/crates/hir_def/src/nameres/tests/diagnostics.rs b/crates/hir_def/src/nameres/tests/diagnostics.rs
index fefdadb22..1ac88fc89 100644
--- a/crates/hir_def/src/nameres/tests/diagnostics.rs
+++ b/crates/hir_def/src/nameres/tests/diagnostics.rs
@@ -233,7 +233,7 @@ fn good_out_dir_diagnostic() {
         macro_rules! concat { () => {} }
 
         include!(concat!(env!("OUT_DIR"), "/out.rs"));
-      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "load out dirs from check" to fix
+      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
         "#,
     );
 }
diff --git a/crates/hir_def/src/path.rs b/crates/hir_def/src/path.rs
index f9c8328f0..b528ff8ba 100644
--- a/crates/hir_def/src/path.rs
+++ b/crates/hir_def/src/path.rs
@@ -289,6 +289,12 @@ impl From<Name> for Path {
     }
 }
 
+impl From<Name> for Box<Path> {
+    fn from(name: Name) -> Box<Path> {
+        Box::new(Path::from(name))
+    }
+}
+
 impl From<Name> for ModPath {
     fn from(name: Name) -> ModPath {
         ModPath::from_segments(PathKind::Plain, iter::once(name))