Fundamental type with suffix not allowed in expression grammar

[tim-dlang]

The following expressions are accepted by DMD, but not allowed by the grammar:

const e1 = int*.init;
const e2 = int[1].init;
const e3 = int*[0].init;

The grammar for PrimaryExpression only allows '(' or '.' after FundamentalType:

PrimaryExpression:
    ...
    FundamentalType . Identifier
    ...
    FundamentalType ( NamedArgumentListopt )
    ...

I assume DMD allows these expressions since this PR: dlang/dmd#14672
The parser contains the comment "defer error for better diagnostics", so maybe the new syntax is not allowed intentionally.

The new syntax is used by a test in druntime: https://github.com/dlang/dmd/blob/fb07d990466f185c2adb19d320627c2723d3978a/druntime/src/core/internal/traits.d#L625