[Issue 12967] New: Prefix method 'this' qualifiers should be disallowed in DeclDefs scope

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=12967

          Issue ID: 12967
           Summary: Prefix method 'this' qualifiers should be disallowed
                    in DeclDefs scope
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: DMD
          Assignee: nob...@puremagic.com
          Reporter: k.hara...@gmail.com

Currently following three function declarations are compiled successfully.

const void prefix_f() {}
const { void block_f() {} }
const: void label_f() {}

But postfix stype method qualifier is disallowed.

void postfix_f() const {}
// Error: function test.postfix_f without 'this' cannot be const

This is introduced by fixing issue 10150.


There's pragmatic reason to accept block and label style.

const { // or label style
    int var = 123;  // qualified with const
    ... many variable declarations -> qualified with const

    void foo() {}   // just ignoring 'const' is useful than making error

    ... more variable declarations -> qualified with const
}

So I think that above behavior should be kept as-is.

But prefix style attributes always modify only one declaration.
So it would be more consistent behavior that raising same error in both prefix
and postfix cases.

const void prefix_f() {}
void postfix_f() const {}
// Error: function test.prefix_f without 'this' cannot be const
// Error: function test.postfix_f without 'this' cannot be const

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