[TVMScript,Fix] Fix findsource when classes are indented

Leaving class definitions was not correctly handled when recreating
scoping information. The fix correctly pops scope whenever the
indentation level becomes less than the current scope.

python/tvm/script/parser/core/diagnostics.py

@@ -163,9 +163,10 @@ def findsource(obj):
                 name = tokens[1].split(":")[0].split("(")[0] + "<locals>"
             elif tokens[0] == "class":
                 name = tokens[1].split(":")[0].split("(")[0]
+            # pop scope if we are less indented
+            while scope_stack and indent_info[scope_stack[-1]] >= indent:
+                scope_stack.pop()
             if name:
-                while scope_stack and indent_info[scope_stack[-1]] >= indent:
-                    scope_stack.pop()
                 scope_stack.append(name)
                 indent_info[name] = indent
                 if scope_stack == qual_names:

tests/python/unittest/test_tvmscript_parser_source.py

@@ -82,5 +82,20 @@ def test_source_ast():
     assert isinstance(for_block, doc.With) and len(for_block.body) == 2
 
 
+def test_nesting_parsing():
+    class dummy:
+        pass
+
+    for i in range(1):
+
+        @tvm.script.ir_module
+        class Module:
+            @T.prim_func
+            def impl(
+                A: T.Buffer[(12, 196, 64), "float32"],
+            ) -> None:
+                T.evaluate(0)
+
+
 if __name__ == "__main__":
     tvm.testing.main()