Fix a bug regarding nested scopes

crates/red_knot_python_semantic/src/semantic_index/builder.rs

@@ -111,8 +111,12 @@ impl<'db> SemanticIndexBuilder<'db> {
             parent,
             kind: node.scope_kind(),
             descendents: children_start..children_start,
+            contained_inside_try_block: self.visiting_try_block,
         };
 
+        // All scopes start off as not visiting a `try` block
+        self.visiting_try_block = false;
+
         let file_scope_id = self.scopes.push(scope);
         self.symbol_tables.push(SymbolTableBuilder::new());
         self.use_def_maps.push(UseDefMapBuilder::new());
@@ -141,6 +145,7 @@ impl<'db> SemanticIndexBuilder<'db> {
         let children_end = self.scopes.next_index();
         let scope = &mut self.scopes[id];
         scope.descendents = scope.descendents.start..children_end;
+        self.visiting_try_block = scope.contained_inside_try_block();
         id
     }
 

crates/red_knot_python_semantic/src/semantic_index/symbol.rs

@@ -164,6 +164,7 @@ pub struct Scope {
     pub(super) parent: Option<FileScopeId>,
     pub(super) kind: ScopeKind,
     pub(super) descendents: Range<FileScopeId>,
+    pub(super) contained_inside_try_block: bool,
 }
 
 impl Scope {
@@ -174,6 +175,11 @@ impl Scope {
     pub fn kind(&self) -> ScopeKind {
         self.kind
     }
+
+    /// Whether this scope is a top-level expression/statement inside a `try` block
+    pub const fn contained_inside_try_block(&self) -> bool {
+        self.contained_inside_try_block
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]

crates/red_knot_python_semantic/src/types/infer.rs

@@ -4970,6 +4970,64 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn inner_try_blocks_inside_separate_scopes_not_tracked_by_outer_block() -> anyhow::Result<()> {
+        let mut db = setup_db();
+
+        db.write_dedented(
+            "src/a.py",
+            "
+            try:
+                x = 1
+
+                def foo():
+                    try:
+                        x = 2
+                        x = 3
+                    except:
+                        x = 4
+
+            except:
+                pass
+            ",
+        )?;
+
+        assert_file_diagnostics(&db, "src/a.py", &[]);
+        assert_public_ty(&db, "src/a.py", "x", "Unbound | Literal[1]");
+        assert_scope_ty(&db, "src/a.py", &["foo"], "x", "Literal[3, 4]");
+
+        Ok(())
+    }
+
+    #[test]
+    fn inner_try_blocks_inside_class_scopes_not_tracked_by_outer_block() -> anyhow::Result<()> {
+        let mut db = setup_db();
+
+        db.write_dedented(
+            "src/a.py",
+            "
+            try:
+                x = 1
+
+                class Foo:
+                    try:
+                        x = 2
+                        x = 3
+                    except:
+                        x = 4
+
+            except:
+                pass
+            ",
+        )?;
+
+        assert_file_diagnostics(&db, "src/a.py", &[]);
+        assert_public_ty(&db, "src/a.py", "x", "Unbound | Literal[1]");
+        assert_scope_ty(&db, "src/a.py", &["Foo"], "x", "Literal[3, 4]");
+
+        Ok(())
+    }
+
     #[test]
     fn basic_comprehension() -> anyhow::Result<()> {
         let mut db = setup_db();