[Issue 22719] New: Fallthrough detection falls through.

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=22719

          Issue ID: 22719
           Summary: Fallthrough detection falls through.
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: deadalnix at gmail.com

Sample code:


import std.stdio;

void foo() {
    writeln(__FUNCTION__);
}

void bar() {
    writeln(__FUNCTION__);
}

void fun(int i) {
    int n = 3;
    switch (i) {
        while (n --> 0)
        case 0:
        case 1:
            foo();
            bar();

        default:
            writeln("default");
    }
}

void main() {
    fun(1);
}


The fun function ought to be parsed as:

void fun(int i) {
    int n = 3;
    switch (i) {
        while (n --> 0) {
        case 0:
        case 1:
            foo();
            bar();
        }
        default:
            writeln("default");
    }
}

The control flow falls through into the default case without a goto default.
This is supposed to be an error in D, but DMD accepts it in this case.

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