Fix hang reporting more (follow-up to #6872) (#6875)

Fix another crash related to hitting max iteration count in
the new semantic analyzer.

Author: JukkaL

mypy/newsemanal/semanal_main.py

@@ -225,7 +225,10 @@ def process_top_level_function(analyzer: 'NewSemanticAnalyzer',
     while deferred:
         iteration += 1
         if iteration == MAX_ITERATIONS:
-            analyzer.report_hang()
+            # Just pick some module inside the current SCC for error context.
+            assert state.tree is not None
+            with analyzer.file_context(state.tree, state.tree.path, state.options):
+                analyzer.report_hang()
             break
         if not (deferred or incomplete) or final_iteration:
             # OK, this is one last pass, now missing names will be reported.

test-data/unit/check-newsemanal.test

@@ -2243,3 +2243,9 @@ force1(reveal_type(var1))            # E: Revealed type is 'Literal[1]'
 class A(A): ...
 [out]
 main: error: Internal error: maximum semantic analysis iteration count reached
+
+[case testNewAnalyzerReportLoopInMRO2]
+def f() -> None:
+    class A(A): ...
+[out]
+main: error: Internal error: maximum semantic analysis iteration count reached