Name shadowing in match statements cause unintuitive type errors

[adabe588@…]

Calling Test.test() gives the error message Error: Invalid pattern: R() of type Integer which is hard to see since m isn't present in the case where the error occurs. This should 1) produce a warning for name shadowing (see #1833), 2) Not cause a type error if shadowing is allowed since m is referenced outside the local variable definitions of the match statements.

package Test

uniontype U
  record R end R;
end U;

function f
  input U m;
algorithm
  _ := match m
    local Integer m;
    case R() then fail();
  end match;
end f;

function test
algorithm
  f(R());
end test;

end Test;

[Martin Sjölund]

It should be a name shadowing error. It is too easy to make things go bad if it doesn't.