diff --git a/mypy/build.py b/mypy/build.py
index ebe2d74f62d6..99effc5e49aa 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -1794,8 +1794,13 @@ def patch_dependency_parents(self) -> None:
         semantic analyzer will perform this patch for us when processing stale
         SCCs.
         """
+        Analyzer = Union[SemanticAnalyzerPass2, NewSemanticAnalyzer]  # noqa
+        if self.manager.options.new_semantic_analyzer:
+            analyzer = self.manager.new_semantic_analyzer  # type: Analyzer
+        else:
+            analyzer = self.manager.semantic_analyzer
         for dep in self.dependencies:
-            self.manager.semantic_analyzer.add_submodules_to_parent_modules(dep, True)
+            analyzer.add_submodules_to_parent_modules(dep, True)
 
     def fix_suppressed_dependencies(self, graph: Graph) -> None:
         """Corrects whether dependencies are considered stale in silent mode.
diff --git a/mypy/newsemanal/semanal.py b/mypy/newsemanal/semanal.py
index b5224bbb81a9..140b1c669e8f 100644
--- a/mypy/newsemanal/semanal.py
+++ b/mypy/newsemanal/semanal.py
@@ -3955,6 +3955,28 @@ def add_symbol(self, name: str, node: SymbolNode, context: Optional[Context],
                                  module_hidden=module_hidden)
         return self.add_symbol_table_node(name, symbol, context)
 
+    def add_symbol_skip_local(self, name: str, node: SymbolNode) -> None:
+        """Same as above, but skipping the local namespace.
+
+        This doesn't check for previous definition and is only used
+        for serialization of method-level classes.
+
+        Classes defined within methods can be exposed through an
+        attribute type, but method-level symbol tables aren't serialized.
+        This method can be used to add such classes to an enclosing,
+        serialized symbol table.
+        """
+        # TODO: currently this is only used by named tuples. Use this method
+        # also by typed dicts and normal classes, see issue #6422.
+        if self.type is not None:
+            names = self.type.names
+            kind = MDEF
+        else:
+            names = self.globals
+            kind = GDEF
+        symbol = SymbolTableNode(kind, node)
+        names[name] = symbol
+
     def current_symbol_table(self) -> SymbolTable:
         if self.is_func_scope():
             assert self.locals[-1] is not None
diff --git a/mypy/newsemanal/semanal_namedtuple.py b/mypy/newsemanal/semanal_namedtuple.py
index f6a0788f1ab2..0a403470df16 100644
--- a/mypy/newsemanal/semanal_namedtuple.py
+++ b/mypy/newsemanal/semanal_namedtuple.py
@@ -179,7 +179,18 @@ def check_namedtuple(self,
             return True, info
         name = cast(Union[StrExpr, BytesExpr, UnicodeExpr], call.args[0]).value
         if name != var_name or is_func_scope:
-            # Give it a unique name derived from the line number.
+            # There are three special cases where need to give it a unique name derived
+            # from the line number:
+            #   * There is a name mismatch with l.h.s., therefore we need to disambiguate
+            #     situations like:
+            #         A = NamedTuple('Same', [('x', int)])
+            #         B = NamedTuple('Same', [('y', str)])
+            #   * This is a base class expression, since it often matches the class name:
+            #         class NT(NamedTuple('NT', [...])):
+            #             ...
+            #   * This is a local (function or method level) named tuple, since
+            #     two methods of a class can define a named tuple with the same name,
+            #     and they will be stored in the same namespace (see below).
             name += '@' + str(call.line)
         if len(defaults) > 0:
             default_items = {
@@ -189,15 +200,31 @@ def check_namedtuple(self,
         else:
             default_items = {}
         info = self.build_namedtuple_typeinfo(name, items, types, default_items)
-        # Store it as a global just in case it would remain anonymous.
-        # (Or in the nearest class if there is one.)
-        self.store_namedtuple_info(info, var_name or name, call, is_typed)
+        # If var_name is not None (i.e. this is not a base class expression), we always
+        # store the generated TypeInfo under var_name in the current scope, so that
+        # other definitions can use it.
+        if var_name:
+            self.store_namedtuple_info(info, var_name, call, is_typed)
+        # There are three cases where we need to store the generated TypeInfo
+        # second time (for the purpose of serialization):
+        #   * If there is a name mismatch like One = NamedTuple('Other', [...])
+        #     we also store the info under name 'Other@lineno', this is needed
+        #     because classes are (de)serialized using their actual fullname, not
+        #     the name of l.h.s.
+        #   * If this is a method level named tuple. It can leak from the method
+        #     via assignment to self attribute and therefore needs to be serialized
+        #     (local namespaces are not serialized).
+        #   * If it is a base class expression. It was not stored above, since
+        #     there is no var_name (but it still needs to be serialized
+        #     since it is in MRO of some class).
+        if name != var_name or is_func_scope:
+            # NOTE: we skip local namespaces since they are not serialized.
+            self.api.add_symbol_skip_local(name, info)
         return True, info
 
     def store_namedtuple_info(self, info: TypeInfo, name: str,
                               call: CallExpr, is_typed: bool) -> None:
-        stnode = SymbolTableNode(GDEF, info)
-        self.api.add_symbol_table_node(name, stnode)
+        self.api.add_symbol(name, info, call)
         call.analyzed = NamedTupleExpr(info, is_typed=is_typed)
         call.analyzed.set_line(call.line, call.column)
 
diff --git a/mypy/newsemanal/semanal_shared.py b/mypy/newsemanal/semanal_shared.py
index ac2efaa4ef87..9aba20be3ee2 100644
--- a/mypy/newsemanal/semanal_shared.py
+++ b/mypy/newsemanal/semanal_shared.py
@@ -5,7 +5,8 @@
 from mypy_extensions import trait
 
 from mypy.nodes import (
-    Context, SymbolTableNode, MypyFile, ImportedName, FuncDef, Node, TypeInfo, Expression, GDEF
+    Context, SymbolTableNode, MypyFile, ImportedName, FuncDef, Node, TypeInfo, Expression, GDEF,
+    SymbolNode
 )
 from mypy.util import correct_relative_import
 from mypy.types import Type, FunctionLike, Instance
@@ -122,7 +123,23 @@ def schedule_patch(self, priority: int, fn: Callable[[], None]) -> None:
 
     @abstractmethod
     def add_symbol_table_node(self, name: str, stnode: SymbolTableNode) -> bool:
-        """Add node to global symbol table (or to nearest class if there is one)."""
+        """Add node to the current symbol table."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def add_symbol(self, name: str, node: SymbolNode, context: Optional[Context],
+                   module_public: bool = True, module_hidden: bool = False) -> bool:
+        """Add symbol to the current symbol table."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def add_symbol_skip_local(self, name: str, node: SymbolNode) -> None:
+        """Add symbol to the current symbol table, skipping locals.
+
+        This is used to store symbol nodes in a symbol table that
+        is going to be serialized (local namespaces are not serialized).
+        See implementation docstring for more details.
+        """
         raise NotImplementedError
 
     @abstractmethod
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index 32a9235585c8..1dc03a460091 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -4931,3 +4931,40 @@ import pack.mod
 import a
 [out]
 [out2]
+
+[case testNewAnalyzerIncrementalBrokenNamedTuple]
+# flags: --new-semantic-analyzer
+import a
+[file a.py]
+from b import NT
+x: NT
+[file a.py.2]
+from b import NT
+x: NT
+reveal_type(x)
+[file b.py]
+from typing import NamedTuple
+NT = NamedTuple('BadName', [('x', int)])
+[out]
+[out2]
+tmp/a.py:3: error: Revealed type is 'Tuple[builtins.int, fallback=b.BadName@2]'
+
+[case testNewAnalyzerIncrementalMethodNamedTuple]
+# flags: --new-semantic-analyzer
+import a
+[file a.py]
+from b import C
+x: C
+[file a.py.2]
+from b import C
+x: C
+reveal_type(x.h)
+[file b.py]
+from typing import NamedTuple
+class C:
+    def __init__(self) -> None:
+        self.h: Hidden
+        Hidden = NamedTuple('Hidden', [('x', int)])
+[out]
+[out2]
+tmp/a.py:3: error: Revealed type is 'Tuple[builtins.int, fallback=b.C.Hidden@5]'