Confusion between use of `|` to combine two dictionaries vs in match-case

Question

we know that | is used to combine two dictionaries, like,

dct_1 = {'a': 1}
dct_2 = {'b': 2}
print(dct_1 | dct_2)

gives,

{'a': 1, 'b': 2}

but if one wants to use the same | in match-case to combine two dictionaries,

x = {'a': 1, 'b': 2}
d = {'a': 1}
c = {'b': 2}
match x:
  case d | c: print(x)

gives error,

SyntaxError: name capture 'd' makes remaining patterns unreachable

as they have made | equivalent to or in match-case. similarly,

match x:
  case ({**d} | {**c}): print(x)

gives,

SyntaxError: alternative patterns bind different names

similarly,

match x:
  case (d | {**c}): print(x)

gives,

SyntaxError: alternative patterns bind different names

and,

match x:
  case ({**d} | c): print(x)

gives,

SyntaxError: alternative patterns bind different names

how do I use | to combine two dictionaries in a case statement?

Answer 1

it appears that the case statement does not care about the assignments,

dct_1 = {'a': 1}
dct_2 = {'b': 2}

if we do,

dct = {'a': 1, 'b': 2}
dct_1 = {'a': 1}
dct_2 = {'b': 2}
match dct:
  case {'a': 1} | {'b': 2}: 
    print("using {'a': 1} | {'b': 2}", dct)

then it outputs,

using {'a': 1} | {'b': 2} {'a': 1, 'b': 2}

so, probably there is nothing wrong with the use of | for dictionaries.

similar situation could be seen here,

dct = {'a': 1, 'b': 2}
eee = '1'
match dct:
  case eee: print("using eee", dct)

which outputs,

using eee {'a': 1, 'b': 2}

here, again case does not care about the assignment,

eee = '1'

and,

case eee:

is more like a wildcard pattern matching

if I do something like this, (using '1' instead of eee in case statement)

dct = {'a': 1, 'b': 2}
eee = '1'
match dct:
  case '1': print("using '1'", dct)

then it would attempt at matching the dictionary dct with '1' and it fails (as expected), so, there is no output.