Merge all or-ed constraints if they have the same structure

Author: sterliakov

mypy/constraints.py

@@ -541,13 +541,14 @@ def any_constraints(options: list[list[Constraint] | None], *, eager: bool) -> l
         # TODO: More generally, if a given (variable, direction) pair appears in
         # every option, combine the bounds with meet/join always, not just for Any.
         trivial_options = select_trivial(valid_options)
-        if trivial_options and len(trivial_options) < len(valid_options):
+        if 0 < len(trivial_options) < len(valid_options):
             merged_options = []
             for option in valid_options:
                 if option in trivial_options:
                     continue
                 merged_options.append([merge_with_any(c) for c in option])
             return any_constraints(list(merged_options), eager=eager)
+        return sum(valid_options, [])
 
     # If normal logic didn't work, try excluding trivially unsatisfiable constraint (due to
     # upper bounds) from each option, and comparing them again.

test-data/unit/check-inference-context.test

@@ -1530,3 +1530,15 @@ def check3(use: bool, val: str) -> "str | Literal[False]":
 def check4(use: bool, val: str) -> "str | bool":
     return use and identity(val)
 [builtins fixtures/tuple.pyi]
+
+[case testDictOrLiteralInContext]
+from typing import Union, Optional, Any
+
+P = dict[str, Union[Optional[str], dict[str, Optional[str]]]]
+
+def f(x: P) -> None:
+    pass
+
+def g(x: Union[dict[str, Any], None], s: Union[str, None]) -> None:
+    f(x or {'x': s})
+[builtins fixtures/dict.pyi]