[dart2wasm] Incorrect ParamInfo for non-nullable non-optional named args with no default values #50587
Description
class Cat {
bool eatFood(String food) => true;
}
class MockCat implements Cat {
dynamic noSuchMethod(Invocation invocation) {
var arg = invocation.positionalArguments[0];
return arg is String && arg.isNotEmpty;
}
}
class MockCat2 extends MockCat {
noSuchMethod(_);
}
class MockCat3 extends MockCat2 implements Cat {
bool eatFood(String food, {double amount});
dynamic noSuchMethod(Invocation invocation) {
if (invocation.memberName == #scratch) {
return invocation.positionalArguments.join(',');
}
return (invocation.positionalArguments[0] as String).isNotEmpty &&
invocation.namedArguments[#amount] > 0.5;
}
}
void main() {
MockCat mock = new MockCat();
print((mock as dynamic).eatFood("cat food"));
print(mock.eatFood(""));
var mock2 = new MockCat2();
print(mock2.eatFood("cat food"));
var mock3 = new MockCat3();
print(mock3.eatFood("cat food", amount: 0.9));
print(mock3.eatFood("cat food", amount: 0.3));
}In this program, the ParamInfo for eatFood selector has a named parameter with NullConstant(null) as the default value of the parameter.
However type of the parameter is f64 and inputs of the Wasm function for this member is [ref #Top, ref Object, f64]. So when we try to initialize the missing non-required named argument with a null value, convertType assumes this is dead code (as null is not a valid f64 value) and generates unreachable.
The problem seems to be the type, which should be nullable. If I print invocation object in noSuchMethod and don't pass amount in the last line, AOT prints {Symbol("amount"): null} as the named arguments. So null should be a valid value for that named argument.