[Issue 20823] New: [DIP 1000] un- at safe code fails with dip1000

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20823

          Issue ID: 20823
           Summary: [DIP 1000] un- at safe code fails with dip1000
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: zero at vec4.xyz

Adding -preview=dip1000 breaks code that is not annotated as @safe.


void boo(T)(T[] data, scope void delegate(T[] data) @nogc fun) {
        fun(data);
} 

void goo(T)(T[] data, /+scope+/ void delegate(T[] data) @nogc fun) {
        fun(data);
} 

int[256] arr;

void main() {
    void Execute(T)(T[] data) @nogc {
        // ...
    }  
    // Works
    goo(arr[0..$], &Execute!int);

    // Compiler error with DIP 1000
    boo(arr[0..$], &Execute!int);      
}

---
Error: template onlineapp.boo cannot deduce function from argument types
!()(int[], void delegate(int[] data) pure nothrow @nogc @safe), candidates are:
onlineapp.d(2):        boo(T)(T[] data, scope void delegate(T[] data) @nogc
fun)
---



https://run.dlang.io/is/mvYgJ9

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