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digitalmars.D.bugs - [Issue 6005] New: Type alias - variable name don't clash

http://d.puremagic.com/issues/show_bug.cgi?id=6005

           Summary: Type alias - variable name don't clash
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: diagnostic
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc



This is D code adapted from a blog post about C language:
http://eli.thegreenplace.net/2011/05/02/the-context-sensitivity-of-c%E2%80%99s-grammar-revisited/

http://www.reddit.com/r/programming/comments/h23h3/the_context_sensitivity_of_cs_grammar_revisited/


Three little D2 programs that compile with no errors. Similar code is allowed
in C too:

------------

alias int Foo;
void foo() {
    Foo bar;
    float Foo;
}
void main() {}

------------

alias int Foo;
void foo() {
    Foo Foo;
    int bar = Foo + 2;
    assert (bar == 2);
}
void main() {}

------------

alias char Foo;
void foo() {
    int bar = Foo.sizeof, Foo, spam = Foo.sizeof;
    assert(bar == 1);
    assert(spam == 4);
}
void main() {}

------------

Is it OK to keep allowing such kind of code in D2 too? Or is it better to
statically forbid it?

A disadvantage of statically disallowing it is the breakage of some valid C
code. On the other hand I don't want to find code like that in D programs.

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May 15 2011