[Issue 24154] New: ImportC: "useless" expression parsed as invalid variable declaration.

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24154

          Issue ID: 24154
           Summary: ImportC: "useless" expression parsed as invalid
                    variable declaration.
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: ImportC
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: dave287091 at gmail.com

ImportC is unable to parse a “useless” expression statement:

    int main(){
        int x = 3;
        x; // Error: type-specifier missing for declaration of `x`
        return x;
    }

This almost never comes up in normal code, but when using gnu statement
expressions, the last expression in the statement expression is the value of
the statement expression and so is often one of these “useless” statements:

    int main(){
        int x = ({
            int ret;
            ret = 3;
            ret; // Error: type-specifier missing for declaration of `ret`
        });
        return x;
    }
The arm_neon.h header has many statement expressions like this.

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