Include same scope

Author: charliermarsh

crates/ty_python_semantic/resources/mdtest/pep695_type_aliases.md

@@ -153,6 +153,17 @@ type Redeclared = int
 type Redeclared = str
 ```
 
+```py
+from random import random
+
+flag = random() > 0.5
+if flag:
+    type BranchRedeclared = int
+else:
+    # error: [invalid-type-alias] "Type alias `BranchRedeclared` is already defined in this scope"
+    type BranchRedeclared = str
+```
+
 ## Generic type aliases
 
 ```py

crates/ty_python_semantic/resources/mdtest/snapshots/pep695_type_aliases.…_-_PEP_695_type_aliases_-_Redeclared_aliases_(7e8460432a17eeae).snap

@@ -13,9 +13,17 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/pep695_type_aliases.md
 ## mdtest_snippet.py
 
 ```
-1 | type Redeclared = int
-2 | # error: [invalid-type-alias] "Type alias `Redeclared` is already defined in this scope"
-3 | type Redeclared = str
+ 1 | type Redeclared = int
+ 2 | # error: [invalid-type-alias] "Type alias `Redeclared` is already defined in this scope"
+ 3 | type Redeclared = str
+ 4 | from random import random
+ 5 | 
+ 6 | flag = random() > 0.5
+ 7 | if flag:
+ 8 |     type BranchRedeclared = int
+ 9 | else:
+10 |     # error: [invalid-type-alias] "Type alias `BranchRedeclared` is already defined in this scope"
+11 |     type BranchRedeclared = str
 ```
 
 # Diagnostics
@@ -29,7 +37,25 @@ error[invalid-type-alias]: Type alias `Redeclared` is already defined in this sc
 2 | # error: [invalid-type-alias] "Type alias `Redeclared` is already defined in this scope"
 3 | type Redeclared = str
   |      ^^^^^^^^^^
+4 | from random import random
   |
 info: rule `invalid-type-alias` is enabled by default
 
 ```
+
+```
+error[invalid-type-alias]: Type alias `BranchRedeclared` is already defined in this scope
+  --> src/mdtest_snippet.py:8:10
+   |
+ 6 | flag = random() > 0.5
+ 7 | if flag:
+ 8 |     type BranchRedeclared = int
+   |          ---------------- `BranchRedeclared` previously defined here
+ 9 | else:
+10 |     # error: [invalid-type-alias] "Type alias `BranchRedeclared` is already defined in this scope"
+11 |     type BranchRedeclared = str
+   |          ^^^^^^^^^^^^^^^^
+   |
+info: rule `invalid-type-alias` is enabled by default
+
+```

crates/ty_python_semantic/src/types/infer/builder.rs

@@ -1510,15 +1510,16 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
         let db = self.db();
         let scope = definition.scope(db);
         let use_def = self.index.use_def_map(scope.file_scope_id(db));
-        let use_id = type_alias_name.scoped_use_id(db, scope);
 
+        // Type alias redeclarations are a scope-level property, so we need all earlier
+        // definitions for this symbol in the scope, not just the bindings reachable here.
         let Some(previous_definition) = use_def
-            .bindings_at_use(use_id)
-            .filter_map(|binding| binding.binding.definition())
-            .filter(|definition| definition.scope(db) == scope)
-            .filter(|definition| {
+            .all_definitions_with_usage()
+            .filter_map(|(_, state, _)| state.definition())
+            .filter(|previous_definition| previous_definition.place(db) == definition.place(db))
+            .filter(|previous_definition| {
                 matches!(
-                    definition.kind(db),
+                    previous_definition.kind(db),
                     DefinitionKind::TypeAlias(previous_type_alias)
                         if previous_type_alias
                             .node(self.module())