fix spans of ImportFromSubmodule

## Summary

I realized we don't really test `DefinitionKind::ImportFromSubmodule` in
the IDE at all, so here's a bunch of them, just recording our current
behaviour.

## Test Plan

*stares at the camera*

crates/ty_ide/src/find_references.rs

@@ -1906,4 +1906,211 @@ func<CURSOR>_alias()
           |
         ");
     }
+
+    #[test]
+    fn references_submodule_import_from_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // TODO(submodule-imports): this should light up both instances of `subpkg`
+        assert_snapshot!(test.references(), @r"
+        info[references]: Reference 1
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn references_submodule_import_from_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg.submod import val
+
+                x = subpkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // TODO(submodule-imports): this should light up both instances of `subpkg`
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_submodule_import_from_wrong_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>mod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // No references is actually correct (or it should only see itself)
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_submodule_import_from_wrong_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.sub<CURSOR>mod import val
+
+                x = submod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // No references is actually correct (or it should only see itself)
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_submodule_import_from_confusing_shadowed_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg import subpkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // No references is actually correct (or it should only see itself)
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_submodule_import_from_confusing_real_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import sub<CURSOR>pkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        assert_snapshot!(test.references(), @r"
+        info[references]: Reference 1
+         --> mypackage/__init__.py:2:21
+          |
+        2 | from .subpkg import subpkg
+          |                     ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+
+        info[references]: Reference 2
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+
+        info[references]: Reference 3
+         --> mypackage/subpkg/__init__.py:2:1
+          |
+        2 | subpkg: int = 10
+          | ^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn references_submodule_import_from_confusing_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import subpkg
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // TODO: this should also highlight the RHS subpkg in the import
+        assert_snapshot!(test.references(), @r"
+        info[references]: Reference 1
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
 }

crates/ty_ide/src/goto_declaration.rs

@@ -2602,6 +2602,295 @@ def ab(a: int, *, c: int): ...
         ");
     }
 
+    #[test]
+    fn goto_declaration_submodule_import_from_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg.submod import val
+          |       ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        info: Source
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_submodule_import_from_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg.submod import val
+
+                x = subpkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // TODO(submodule-imports): I don't *think* this is what we want..?
+        // It's a bit confusing because this symbol is essentially the LHS *and* RHS of
+        // `subpkg = mypackage.subpkg`. As in, it's both defining a local `subpkg` and
+        // loading the module `mypackage.subpkg`, so, it's understandable to get confused!
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+        --> mypackage/subpkg/__init__.py:1:1
+         |
+         |
+        info: Source
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg.submod import val
+          |       ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_submodule_import_from_wrong_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>mod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // No result is correct!
+        assert_snapshot!(test.goto_declaration(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_declaration_submodule_import_from_wrong_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.sub<CURSOR>mod import val
+
+                x = submod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // Going to the submod module is correct!
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mypackage/subpkg/submod.py:1:1
+          |
+        1 |
+          | ^
+        2 | val: int = 0
+          |
+        info: Source
+         --> mypackage/__init__.py:2:14
+          |
+        2 | from .subpkg.submod import val
+          |              ^^^^^^
+        3 |
+        4 | x = submod
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_submodule_import_from_confusing_shadowed_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg import subpkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // Going to the subpkg module is correct!
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mypackage/subpkg/__init__.py:1:1
+          |
+        1 |
+          | ^
+        2 | subpkg: int = 10
+          |
+        info: Source
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg import subpkg
+          |       ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_submodule_import_from_confusing_real_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import sub<CURSOR>pkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // Going to the subpkg `int` is correct!
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mypackage/subpkg/__init__.py:2:1
+          |
+        2 | subpkg: int = 10
+          | ^^^^^^
+          |
+        info: Source
+         --> mypackage/__init__.py:2:21
+          |
+        2 | from .subpkg import subpkg
+          |                     ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_declaration_submodule_import_from_confusing_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import subpkg
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // TODO(submodule-imports): Ok this one is FASCINATING but definitely wrong!
+        //
+        // So there's 3 relevant definitions here:
+        //
+        // * `subpkg: int = 10` in the other file is in fact the original definition.
+        //    Including it here is accurate and possibly useful?
+        //
+        // *  the LHS `subpkg` in the import is an instance of `subpkg = ...`
+        //    because it's a `DefinitionKind::ImportFromSubmodle`.
+        //    Including it here is Pedantically Correct but Unhelpful.
+        //
+        // * `the RHS `subpkg` in the import is a second instance of `subpkg = ...`
+        //    that *immediately* overwrites the `ImportFromSubmodule`'s definition.
+        //    This is the most important one and doesn't show up at all! Sadness!
+        assert_snapshot!(test.goto_declaration(), @r"
+        info[goto-declaration]: Declaration
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg import subpkg
+          |       ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        info: Source
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+
+        info[goto-declaration]: Declaration
+         --> mypackage/subpkg/__init__.py:2:1
+          |
+        2 | subpkg: int = 10
+          | ^^^^^^
+          |
+        info: Source
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
+
     impl CursorTest {
         fn goto_declaration(&self) -> String {
             let Some(targets) = goto_declaration(&self.db, self.cursor.file, self.cursor.offset)

crates/ty_ide/src/goto_type_definition.rs

@@ -1672,6 +1672,283 @@ def function():
         "#);
     }
 
+    #[test]
+    fn goto_type_submodule_import_from_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // The module is the correct type definition
+        assert_snapshot!(test.goto_type_definition(), @r"
+        info[goto-type-definition]: Type definition
+        --> mypackage/subpkg/__init__.py:1:1
+         |
+         |
+        info: Source
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_type_submodule_import_from_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg.submod import val
+
+                x = subpkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // The module is the correct type definition
+        assert_snapshot!(test.goto_type_definition(), @r"
+        info[goto-type-definition]: Type definition
+        --> mypackage/subpkg/__init__.py:1:1
+         |
+         |
+        info: Source
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg.submod import val
+          |       ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_type_submodule_import_from_wrong_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>mod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // Unknown is correct, `submod` is not in scope
+        assert_snapshot!(test.goto_type_definition(), @r"
+        info[goto-type-definition]: Type definition
+          --> stdlib/ty_extensions.pyi:20:1
+           |
+        19 | # Types
+        20 | Unknown = object()
+           | ^^^^^^^
+        21 | AlwaysTruthy = object()
+        22 | AlwaysFalsy = object()
+           |
+        info: Source
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = submod
+          |     ^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_type_submodule_import_from_wrong_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.sub<CURSOR>mod import val
+
+                x = submod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // The module is correct
+        assert_snapshot!(test.goto_type_definition(), @r"
+        info[goto-type-definition]: Type definition
+         --> mypackage/subpkg/submod.py:1:1
+          |
+        1 | /
+        2 | | val: int = 0
+          | |_____________^
+          |
+        info: Source
+         --> mypackage/__init__.py:2:14
+          |
+        2 | from .subpkg.submod import val
+          |              ^^^^^^
+        3 |
+        4 | x = submod
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_type_submodule_import_from_confusing_shadowed_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg import subpkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // The module is correct
+        assert_snapshot!(test.goto_type_definition(), @r"
+        info[goto-type-definition]: Type definition
+         --> mypackage/subpkg/__init__.py:1:1
+          |
+        1 | /
+        2 | | subpkg: int = 10
+          | |_________________^
+          |
+        info: Source
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg import subpkg
+          |       ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn goto_type_submodule_import_from_confusing_real_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import sub<CURSOR>pkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // `int` is correct
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+           --> stdlib/builtins.pyi:348:7
+            |
+        347 | @disjoint_base
+        348 | class int:
+            |       ^^^
+        349 |     """int([x]) -> integer
+        350 |     int(x, base=10) -> integer
+            |
+        info: Source
+         --> mypackage/__init__.py:2:21
+          |
+        2 | from .subpkg import subpkg
+          |                     ^^^^^^
+        3 |
+        4 | x = subpkg
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_submodule_import_from_confusing_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import subpkg
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // `int` is correct
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+           --> stdlib/builtins.pyi:348:7
+            |
+        347 | @disjoint_base
+        348 | class int:
+            |       ^^^
+        349 |     """int([x]) -> integer
+        350 |     int(x, base=10) -> integer
+            |
+        info: Source
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        "#);
+    }
+
     impl CursorTest {
         fn goto_type_definition(&self) -> String {
             let Some(targets) =

crates/ty_ide/src/hover.rs

@@ -3321,6 +3321,297 @@ def function():
         ");
     }
 
+    #[test]
+    fn hover_submodule_import_from_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // The module is correct
+        assert_snapshot!(test.hover(), @r"
+        <module 'mypackage.subpkg'>
+        ---------------------------------------------
+        ```python
+        <module 'mypackage.subpkg'>
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = subpkg
+          |     ^^^-^^
+          |     |  |
+          |     |  Cursor offset
+          |     source
+          |
+        ");
+    }
+
+    #[test]
+    fn hover_submodule_import_from_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg.submod import val
+
+                x = subpkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // The module is correct
+        assert_snapshot!(test.hover(), @r"
+        <module 'mypackage.subpkg'>
+        ---------------------------------------------
+        ```python
+        <module 'mypackage.subpkg'>
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg.submod import val
+          |       ^^^-^^
+          |       |  |
+          |       |  Cursor offset
+          |       source
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn hover_submodule_import_from_wrong_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>mod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // Unknown is correct
+        assert_snapshot!(test.hover(), @r"
+        Unknown
+        ---------------------------------------------
+        ```python
+        Unknown
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = submod
+          |     ^^^-^^
+          |     |  |
+          |     |  Cursor offset
+          |     source
+          |
+        ");
+    }
+
+    #[test]
+    fn hover_submodule_import_from_wrong_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.sub<CURSOR>mod import val
+
+                x = submod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // The submodule is correct
+        assert_snapshot!(test.hover(), @r"
+        <module 'mypackage.subpkg.submod'>
+        ---------------------------------------------
+        ```python
+        <module 'mypackage.subpkg.submod'>
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:2:14
+          |
+        2 | from .subpkg.submod import val
+          |              ^^^-^^
+          |              |  |
+          |              |  Cursor offset
+          |              source
+        3 |
+        4 | x = submod
+          |
+        ");
+    }
+
+    #[test]
+    fn hover_submodule_import_from_confusing_shadowed_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg import subpkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // The module is correct
+        assert_snapshot!(test.hover(), @r"
+        <module 'mypackage.subpkg'>
+        ---------------------------------------------
+        ```python
+        <module 'mypackage.subpkg'>
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:2:7
+          |
+        2 | from .subpkg import subpkg
+          |       ^^^-^^
+          |       |  |
+          |       |  Cursor offset
+          |       source
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn hover_submodule_import_from_confusing_real_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import sub<CURSOR>pkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // int is correct
+        assert_snapshot!(test.hover(), @r"
+        int
+        ---------------------------------------------
+        ```python
+        int
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:2:21
+          |
+        2 | from .subpkg import subpkg
+          |                     ^^^-^^
+          |                     |  |
+          |                     |  Cursor offset
+          |                     source
+        3 |
+        4 | x = subpkg
+          |
+        ");
+    }
+
+    #[test]
+    fn hover_submodule_import_from_confusing_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import subpkg
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // int is correct
+        assert_snapshot!(test.hover(), @r"
+        int
+        ---------------------------------------------
+        ```python
+        int
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^-^^
+          |     |  |
+          |     |  Cursor offset
+          |     source
+          |
+        ");
+    }
+
     impl CursorTest {
         fn hover(&self) -> String {
             use std::fmt::Write;

crates/ty_ide/src/rename.rs

@@ -1223,4 +1223,207 @@ result = func(10, y=20)
 
         assert_snapshot!(test.rename("z"), @"Cannot rename");
     }
+
+    #[test]
+    fn rename_submodule_import_from_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // TODO(submodule-imports): we should refuse to rename this (it's the name of a module)
+        assert_snapshot!(test.rename("mypkg"), @r"
+        info[rename]: Rename symbol (found 1 locations)
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg.submod import val
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn rename_submodule_import_from_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg.submod import val
+
+                x = subpkg
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // Refusing to rename is correct
+        assert_snapshot!(test.rename("mypkg"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_submodule_import_from_wrong_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.submod import val
+
+                x = sub<CURSOR>mod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // Refusing to rename is good/fine here, it's an undefined reference
+        assert_snapshot!(test.rename("mypkg"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_submodule_import_from_wrong_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg.sub<CURSOR>mod import val
+
+                x = submod
+                "#,
+            )
+            .source("mypackage/subpkg/__init__.py", r#""#)
+            .source(
+                "mypackage/subpkg/submod.py",
+                r#"
+                val: int = 0
+                "#,
+            )
+            .build();
+
+        // Refusing to rename is good here, it's a module name
+        assert_snapshot!(test.rename("mypkg"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_submodule_import_from_confusing_shadowed_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .sub<CURSOR>pkg import subpkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // Refusing to rename is good here, it's the name of a module
+        assert_snapshot!(test.rename("mypkg"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_submodule_import_from_confusing_real_def() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import sub<CURSOR>pkg
+
+                x = subpkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // Renaming the integer is correct
+        assert_snapshot!(test.rename("mypkg"), @r"
+        info[rename]: Rename symbol (found 3 locations)
+         --> mypackage/__init__.py:2:21
+          |
+        2 | from .subpkg import subpkg
+          |                     ^^^^^^
+        3 |
+        4 | x = subpkg
+          |     ------
+          |
+         ::: mypackage/subpkg/__init__.py:2:1
+          |
+        2 | subpkg: int = 10
+          | ------
+          |
+        ");
+    }
+
+    #[test]
+    fn rename_submodule_import_from_confusing_use() {
+        let test = CursorTest::builder()
+            .source(
+                "mypackage/__init__.py",
+                r#"
+                from .subpkg import subpkg
+
+                x = sub<CURSOR>pkg
+                "#,
+            )
+            .source(
+                "mypackage/subpkg/__init__.py",
+                r#"
+                subpkg: int = 10
+                "#,
+            )
+            .build();
+
+        // TODO(submodule-imports): this is incorrect, we should rename the `subpkg` int
+        // and the RHS of the import statement (but *not* rename the LHS).
+        //
+        // However us being cautious here *would* be good as the rename will actually
+        // result in a `subpkg` variable still existing in this code, as the import's LHS
+        // `DefinitionKind::ImportFromSubmodule` would stop being overwritten by the RHS!
+        assert_snapshot!(test.rename("mypkg"), @r"
+        info[rename]: Rename symbol (found 1 locations)
+         --> mypackage/__init__.py:4:5
+          |
+        2 | from .subpkg import subpkg
+        3 |
+        4 | x = subpkg
+          |     ^^^^^^
+          |
+        ");
+    }
 }

crates/ty_python_semantic/src/semantic_index/builder.rs

@@ -1529,7 +1529,7 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
                     // Record whether this is equivalent to `from . import ...`
                     is_self_import = module_name == thispackage;
 
-                    if node.module.is_some()
+                    if let Some(module_node) = &node.module
                         && let Some(relative_submodule) = module_name.relative_to(&thispackage)
                         && let Some(direct_submodule) = relative_submodule.components().next()
                         && !self.seen_submodule_imports.contains(direct_submodule)
@@ -1540,9 +1540,23 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
 
                         let direct_submodule_name = Name::new(direct_submodule);
                         let symbol = self.add_symbol(direct_submodule_name);
+
+                        let module_index = if node.level == 0 {
+                            // "whatever.thispackage.x.y" we want `x`
+                            thispackage.components().count()
+                        } else {
+                            // ".x.y" we want `x` (level 1 => index 0)
+                            // "..x.y" we want `y` (level 2 => index 1)
+                            // (The Identifier doesn't include the prefix dots)
+                            node.level as usize - 1
+                        };
                         self.add_definition(
                             symbol.into(),
-                            ImportFromSubmoduleDefinitionNodeRef { node },
+                            ImportFromSubmoduleDefinitionNodeRef {
+                                node,
+                                module: module_node,
+                                module_index,
+                            },
                         );
                     }
                 }

crates/ty_python_semantic/src/semantic_index/definition.rs

@@ -3,7 +3,7 @@ use std::ops::Deref;
 use ruff_db::files::{File, FileRange};
 use ruff_db::parsed::{ParsedModuleRef, parsed_module};
 use ruff_python_ast as ast;
-use ruff_text_size::{Ranged, TextRange};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
 use crate::Db;
 use crate::ast_node_ref::AstNodeRef;
@@ -374,6 +374,8 @@ pub(crate) struct ImportFromDefinitionNodeRef<'ast> {
 #[derive(Copy, Clone, Debug)]
 pub(crate) struct ImportFromSubmoduleDefinitionNodeRef<'ast> {
     pub(crate) node: &'ast ast::StmtImportFrom,
+    pub(crate) module: &'ast ast::Identifier,
+    pub(crate) module_index: usize,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -456,8 +458,12 @@ impl<'db> DefinitionNodeRef<'_, 'db> {
             }),
             DefinitionNodeRef::ImportFromSubmodule(ImportFromSubmoduleDefinitionNodeRef {
                 node,
+                module,
+                module_index,
             }) => DefinitionKind::ImportFromSubmodule(ImportFromSubmoduleDefinitionKind {
                 node: AstNodeRef::new(parsed, node),
+                module: AstNodeRef::new(parsed, module),
+                module_index,
             }),
             DefinitionNodeRef::ImportStar(star_import) => {
                 let StarImportDefinitionNodeRef { node, symbol_id } = star_import;
@@ -584,7 +590,9 @@ impl<'db> DefinitionNodeRef<'_, 'db> {
                 alias_index,
                 is_reexported: _,
             }) => (&node.names[alias_index]).into(),
-            Self::ImportFromSubmodule(ImportFromSubmoduleDefinitionNodeRef { node }) => node.into(),
+            Self::ImportFromSubmodule(ImportFromSubmoduleDefinitionNodeRef { node, .. }) => {
+                node.into()
+            }
             // INVARIANT: for an invalid-syntax statement such as `from foo import *, bar, *`,
             // we only create a `StarImportDefinitionKind` for the *first* `*` alias in the names list.
             Self::ImportStar(StarImportDefinitionNodeRef { node, symbol_id: _ }) => node
@@ -755,7 +763,7 @@ impl DefinitionKind<'_> {
         match self {
             DefinitionKind::Import(import) => import.alias(module).range(),
             DefinitionKind::ImportFrom(import) => import.alias(module).range(),
-            DefinitionKind::ImportFromSubmodule(import) => import.import(module).range(),
+            DefinitionKind::ImportFromSubmodule(import) => import.target_range(module),
             DefinitionKind::StarImport(import) => import.alias(module).range(),
             DefinitionKind::Function(function) => function.node(module).name.range(),
             DefinitionKind::Class(class) => class.node(module).name.range(),
@@ -793,7 +801,7 @@ impl DefinitionKind<'_> {
         match self {
             DefinitionKind::Import(import) => import.alias(module).range(),
             DefinitionKind::ImportFrom(import) => import.alias(module).range(),
-            DefinitionKind::ImportFromSubmodule(import) => import.import(module).range(),
+            DefinitionKind::ImportFromSubmodule(import) => import.module(module).range(),
             DefinitionKind::StarImport(import) => import.import(module).range(),
             DefinitionKind::Function(function) => function.node(module).range(),
             DefinitionKind::Class(class) => class.node(module).range(),
@@ -1033,12 +1041,37 @@ impl ImportFromDefinitionKind {
 #[derive(Clone, Debug, get_size2::GetSize)]
 pub struct ImportFromSubmoduleDefinitionKind {
     node: AstNodeRef<ast::StmtImportFrom>,
+    module: AstNodeRef<ast::Identifier>,
+    module_index: usize,
 }
 
 impl ImportFromSubmoduleDefinitionKind {
     pub fn import<'ast>(&self, module: &'ast ParsedModuleRef) -> &'ast ast::StmtImportFrom {
         self.node.node(module)
     }
+
+    pub fn module<'ast>(&self, module: &'ast ParsedModuleRef) -> &'ast ast::Identifier {
+        self.module.node(module)
+    }
+
+    pub fn target_range(&self, module: &ParsedModuleRef) -> TextRange {
+        let module_ident = self.module(module);
+        let module_str = module_ident.as_str();
+        let Some(component_str) = module_str.split('.').nth(self.module_index) else {
+            // This shouldn't happen but just in case, provide a safe default
+            return module_ident.range();
+        };
+        let base_addr = module_str.as_ptr().addr();
+        let component_addr = component_str.as_ptr().addr();
+        let offset = base_addr.saturating_sub(component_addr);
+        let Ok(offset_size) = TextSize::try_from(offset) else {
+            // This shouldn't happen but just in case, provide a safe default
+            return module_ident.range();
+        };
+        let start = module_ident.start().saturating_add(offset_size);
+        let end = start.saturating_add(component_str.text_len());
+        TextRange::new(start, end)
+    }
 }
 
 #[derive(Clone, Debug, get_size2::GetSize)]