allow `from` imports in nonglobal scopes to add available submodule attributes

crates/ty_python_semantic/resources/mdtest/import/tracking.md

@@ -116,3 +116,43 @@ b = 1
 
 ```py
 ```
+
+## Submodule is loaded in a non-global scope
+
+We recognise submodules as being available as attributes even if they are loaded in a function
+scope. The function might never be executed, which means that the submodule might never be loaded;
+however, we prefer to prioritise avoiding false positives over catching all possible errors here.
+
+`a/b.py`:
+
+```py
+```
+
+`a/c.py`:
+
+```py
+d = 42
+```
+
+`a/e/f.py`:
+
+```py
+```
+
+`main.py`:
+
+```py
+import a
+
+def f():
+    import a.b
+    from a.c import d
+    from a.e import f
+
+f()
+
+reveal_type(a.b)  # revealed: <module 'a.b'>
+reveal_type(a.c)  # revealed: <module 'a.c'>
+reveal_type(a.e)  # revealed: <module 'a.e'>
+reveal_type(a.e.f)  # revealed: <module 'a.e.f'>
+```

crates/ty_python_semantic/src/semantic_index/builder.rs

@@ -1531,11 +1531,12 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
                         is_self_import = &module_name == thispackage;
                     }
 
-                    if self.current_scope().is_global() && node.module.is_some() {
+                    if node.module.is_some() {
                         if let Ok(thispackage) = this_package
                             && let Some(relative_submodule) = module_name.relative_to(&thispackage)
                         {
                             if is_package
+                                && self.current_scope().is_global()
                                 && let Some(direct_submodule) =
                                     relative_submodule.components().next()
                                 && !self.seen_submodule_imports.contains(direct_submodule)