[Issue 21570] New: __traits(isStaticArray, ...) accepts enums with static array as base type

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21570

          Issue ID: 21570
           Summary: __traits(isStaticArray, ...) accepts enums with static
                    array as base type
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: moonlightsentinel at disroot.org

Example:
-----------------------------------------------------------------

enum EnumArray : int[2] {
    a = [ 1, 2 ],
    b = [ 3, 4 ]
}

static assert(!__traits(isStaticArray, EnumArray)); // Fails

// Expected equal behaviour of trait and is-expression
static assert(!is(EnumArray == T[n], T, size_t n)); // Passes

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

The spec[1] states that a named enum creates a distinct type which is
implicitly convertible to it's base type. So EnumArray is not a static array
and __traits(isStaticArray, EnumArray) should yield `false` as done for the
equivalent is-expression.

[1] https://dlang.org/spec/enum.html#named_enums

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