From 2633e23f2bf0649031b887309cda1fecae063084 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonas.schievink@ferrous-systems.com>
Date: Mon, 22 Mar 2021 18:47:19 +0100
Subject: resolver: manually traverse nested block scopes

---
 crates/hir_def/src/nameres.rs                 | 17 +++++++++++++++++
 crates/hir_def/src/nameres/path_resolution.rs |  2 +-
 crates/hir_def/src/resolver.rs                | 18 ++++++++++++++----
 crates/hir_ty/src/tests/regression.rs         | 13 +++++++++++++
 4 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/crates/hir_def/src/nameres.rs b/crates/hir_def/src/nameres.rs
index 0d3a0b54f..9e8e4e9ec 100644
--- a/crates/hir_def/src/nameres.rs
+++ b/crates/hir_def/src/nameres.rs
@@ -322,6 +322,23 @@ impl DefMap {
         (res.resolved_def, res.segment_index)
     }
 
+    pub(crate) fn resolve_path_locally(
+        &self,
+        db: &dyn DefDatabase,
+        original_module: LocalModuleId,
+        path: &ModPath,
+        shadow: BuiltinShadowMode,
+    ) -> (PerNs, Option<usize>) {
+        let res = self.resolve_path_fp_with_macro_single(
+            db,
+            ResolveMode::Other,
+            original_module,
+            path,
+            shadow,
+        );
+        (res.resolved_def, res.segment_index)
+    }
+
     /// Ascends the `DefMap` hierarchy and calls `f` with every `DefMap` and containing module.
     ///
     /// If `f` returns `Some(val)`, iteration is stopped and `Some(val)` is returned. If `f` returns
diff --git a/crates/hir_def/src/nameres/path_resolution.rs b/crates/hir_def/src/nameres/path_resolution.rs
index db459b1ed..60471937c 100644
--- a/crates/hir_def/src/nameres/path_resolution.rs
+++ b/crates/hir_def/src/nameres/path_resolution.rs
@@ -156,7 +156,7 @@ impl DefMap {
         }
     }
 
-    fn resolve_path_fp_with_macro_single(
+    pub(super) fn resolve_path_fp_with_macro_single(
         &self,
         db: &dyn DefDatabase,
         mode: ResolveMode,
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index 04ea9c5d7..a73585ee7 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -548,7 +548,7 @@ impl ModuleItemMap {
         path: &ModPath,
     ) -> Option<ResolveValueResult> {
         let (module_def, idx) =
-            self.def_map.resolve_path(db, self.module_id, &path, BuiltinShadowMode::Other);
+            self.def_map.resolve_path_locally(db, self.module_id, &path, BuiltinShadowMode::Other);
         match idx {
             None => {
                 let value = to_value_ns(module_def)?;
@@ -578,7 +578,7 @@ impl ModuleItemMap {
         path: &ModPath,
     ) -> Option<(TypeNs, Option<usize>)> {
         let (module_def, idx) =
-            self.def_map.resolve_path(db, self.module_id, &path, BuiltinShadowMode::Other);
+            self.def_map.resolve_path_locally(db, self.module_id, &path, BuiltinShadowMode::Other);
         let res = to_type_ns(module_def)?;
         Some((res, idx))
     }
@@ -627,8 +627,18 @@ pub trait HasResolver: Copy {
 
 impl HasResolver for ModuleId {
     fn resolver(self, db: &dyn DefDatabase) -> Resolver {
-        let def_map = self.def_map(db);
-        Resolver::default().push_module_scope(def_map, self.local_id)
+        let mut def_map = self.def_map(db);
+        let mut modules = Vec::new();
+        modules.push((def_map.clone(), self.local_id));
+        while let Some(parent) = def_map.parent() {
+            def_map = parent.def_map(db);
+            modules.push((def_map.clone(), parent.local_id));
+        }
+        let mut resolver = Resolver::default();
+        for (def_map, module) in modules.into_iter().rev() {
+            resolver = resolver.push_module_scope(def_map, module);
+        }
+        resolver
     }
 }
 
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index 69314e245..b69f86050 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -961,3 +961,16 @@ fn issue_6852() {
         "#]],
     );
 }
+
+#[test]
+fn param_overrides_fn() {
+    check_types(
+        r#"
+        fn example(example: i32) {
+            fn f() {}
+            example;
+          //^^^^^^^ i32
+        }
+        "#,
+    )
+}
-- 
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