Merge #7614

7614: Unleash inner item resolution to users r=jonas-schievink a=jonas-schievink

![Peek 2021-02-09 17-30](https://user-images.githubusercontent.com/1786438/107394800-8627f300-6afc-11eb-8662-ed07226bc58f.gif)


Co-authored-by: Jonas Schievink <[email protected]>

3 files changed, 49 insertions, 104 deletions

diff --git a/crates/hir_def/src/body/scope.rs b/crates/hir_def/src/body/scope.rs
index 49f1427b4..210b4a617 100644
--- a/crates/hir_def/src/body/scope.rs
+++ b/crates/hir_def/src/body/scope.rs
@@ -9,7 +9,7 @@ use crate::{
     body::Body,
     db::DefDatabase,
     expr::{Expr, ExprId, Pat, PatId, Statement},
-    DefWithBodyId,
+    BlockId, DefWithBodyId,
 };
 
 pub type ScopeId = Idx<ScopeData>;
@@ -39,6 +39,7 @@ impl ScopeEntry {
 #[derive(Debug, PartialEq, Eq)]
 pub struct ScopeData {
     parent: Option<ScopeId>,
+    block: Option<BlockId>,
     entries: Vec<ScopeEntry>,
 }
 
@@ -61,6 +62,11 @@ impl ExprScopes {
         &self.scopes[scope].entries
     }
 
+    /// If `scope` refers to a block expression scope, returns the corresponding `BlockId`.
+    pub fn block(&self, scope: ScopeId) -> Option<BlockId> {
+        self.scopes[scope].block
+    }
+
     pub fn scope_chain(&self, scope: Option<ScopeId>) -> impl Iterator<Item = ScopeId> + '_ {
         std::iter::successors(scope, move |&scope| self.scopes[scope].parent)
     }
@@ -79,11 +85,15 @@ impl ExprScopes {
     }
 
     fn root_scope(&mut self) -> ScopeId {
-        self.scopes.alloc(ScopeData { parent: None, entries: vec![] })
+        self.scopes.alloc(ScopeData { parent: None, block: None, entries: vec![] })
     }
 
     fn new_scope(&mut self, parent: ScopeId) -> ScopeId {
-        self.scopes.alloc(ScopeData { parent: Some(parent), entries: vec![] })
+        self.scopes.alloc(ScopeData { parent: Some(parent), block: None, entries: vec![] })
+    }
+
+    fn new_block_scope(&mut self, parent: ScopeId, block: BlockId) -> ScopeId {
+        self.scopes.alloc(ScopeData { parent: Some(parent), block: Some(block), entries: vec![] })
     }
 
     fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
@@ -136,7 +146,11 @@ fn compute_block_scopes(
 fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut ExprScopes, scope: ScopeId) {
     scopes.set_scope(expr, scope);
     match &body[expr] {
-        Expr::Block { statements, tail, .. } => {
+        Expr::Block { statements, tail, id, .. } => {
+            let scope = scopes.new_block_scope(scope, *id);
+            // Overwrite the old scope for the block expr, so that every block scope can be found
+            // via the block itself (important for blocks that only contain items, no expressions).
+            scopes.set_scope(expr, scope);
             compute_block_scopes(&statements, *tail, body, scopes, scope);
         }
         Expr::For { iterable, pat, body: body_expr, .. } => {
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index a92134ba7..bb43569d7 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -1,10 +1,10 @@
 mod block;
 
-use base_db::{fixture::WithFixture, FilePosition, SourceDatabase};
+use base_db::{fixture::WithFixture, SourceDatabase};
 use expect_test::Expect;
 use test_utils::mark;
 
-use crate::{test_db::TestDB, BlockId, ModuleDefId};
+use crate::{test_db::TestDB, ModuleDefId};
 
 use super::*;
 
@@ -37,104 +37,8 @@ fn check_diagnostics(ra_fixture: &str) {
 fn block_def_map_at(ra_fixture: &str) -> String {
     let (db, position) = crate::test_db::TestDB::with_position(ra_fixture);
 
-    let krate = db.crate_graph().iter().next().unwrap();
-    let def_map = db.crate_def_map(krate);
-
-    let mut block =
-        block_at_pos(&db, &def_map, position).expect("couldn't find enclosing function or block");
-    loop {
-        let def_map = db.block_def_map(block).unwrap_or_else(|| def_map.clone());
-        let new_block = block_at_pos(&db, &def_map, position);
-        match new_block {
-            Some(new_block) => {
-                assert_ne!(block, new_block);
-                block = new_block;
-            }
-            None => {
-                return def_map.dump(&db);
-            }
-        }
-    }
-}
-
-fn block_at_pos(db: &dyn DefDatabase, def_map: &DefMap, position: FilePosition) -> Option<BlockId> {
-    // Find the smallest (innermost) function containing the cursor.
-    let mut size = None;
-    let mut fn_def = None;
-    for (_, module) in def_map.modules() {
-        let file_id = module.definition_source(db).file_id;
-        if file_id != position.file_id.into() {
-            continue;
-        }
-        let root = db.parse_or_expand(file_id).unwrap();
-        let ast_map = db.ast_id_map(file_id);
-        let item_tree = db.item_tree(file_id);
-        for decl in module.scope.declarations() {
-            if let ModuleDefId::FunctionId(it) = decl {
-                let ast = ast_map.get(item_tree[it.lookup(db).id.value].ast_id).to_node(&root);
-                let range = ast.syntax().text_range();
-
-                if !range.contains(position.offset) {
-                    continue;
-                }
-
-                let new_size = match size {
-                    None => range.len(),
-                    Some(size) => {
-                        if range.len() < size {
-                            range.len()
-                        } else {
-                            size
-                        }
-                    }
-                };
-                if size != Some(new_size) {
-                    size = Some(new_size);
-                    fn_def = Some(it);
-                }
-            }
-        }
-    }
-
-    let (body, source_map) = db.body_with_source_map(fn_def?.into());
-
-    // Now find the smallest encompassing block expression in the function body.
-    let mut size = None;
-    let mut block_id = None;
-    for (expr_id, expr) in body.exprs.iter() {
-        if let Expr::Block { id, .. } = expr {
-            if let Ok(ast) = source_map.expr_syntax(expr_id) {
-                if ast.file_id != position.file_id.into() {
-                    continue;
-                }
-
-                let root = db.parse_or_expand(ast.file_id).unwrap();
-                let ast = ast.value.to_node(&root);
-                let range = ast.syntax().text_range();
-
-                if !range.contains(position.offset) {
-                    continue;
-                }
-
-                let new_size = match size {
-                    None => range.len(),
-                    Some(size) => {
-                        if range.len() < size {
-                            range.len()
-                        } else {
-                            size
-                        }
-                    }
-                };
-                if size != Some(new_size) {
-                    size = Some(new_size);
-                    block_id = Some(*id);
-                }
-            }
-        }
-    }
-
-    Some(block_id.expect("can't find block containing cursor"))
+    let module = db.module_at_position(position);
+    module.def_map(&db).dump(&db)
 }
 
 fn check_at(ra_fixture: &str, expect: Expect) {
diff --git a/crates/hir_def/src/body/tests/block.rs b/crates/hir_def/src/body/tests/block.rs
index b599c6269..a5ec0883f 100644
--- a/crates/hir_def/src/body/tests/block.rs
+++ b/crates/hir_def/src/body/tests/block.rs
@@ -232,3 +232,30 @@ fn f() {
         "#]],
     )
 }
+
+#[test]
+fn super_does_not_resolve_to_block_module() {
+    check_at(
+        r#"
+fn main() {
+    struct Struct {}
+    mod module {
+        use super::Struct;
+
+        $0
+    }
+}
+    "#,
+        expect![[r#"
+        block scope
+        Struct: t
+        module: t
+
+        block scope::module
+        Struct: _
+
+        crate
+        main: v
+    "#]],
+    );
+}