Fix Issue 18920 - core.internal.hash of array of scalars should be @safe

Author: n8sh

src/core/internal/hash.d

@@ -58,7 +58,7 @@ if (!is(T == enum) && !is(T : typeof(null)) && is(T S: S[]) && !__traits(isStati
     //ubyteble array (arithmetic types and structs without toHash) CTFE ready for arithmetic types and structs without reference fields
     {
         auto bytes = toUbyte(val);
-        return bytesHash(bytes.ptr, bytes.length, seed);
+        return (() @trusted => bytesHash(bytes.ptr, bytes.length, seed))();
     }
     else //Other types. CTFE unsupported
     {
@@ -67,6 +67,12 @@ if (!is(T == enum) && !is(T : typeof(null)) && is(T S: S[]) && !__traits(isStati
     }
 }
 
+@nogc nothrow pure @safe unittest // issue 18918
+{
+    // Check hashOf dynamic array of scalars is usable in @safe code.
+    const _ = hashOf("abc");
+}
+
 //arithmetic type hash
 @trusted nothrow pure
 size_t hashOf(T)(auto ref T val, size_t seed = 0) if (!is(T == enum) && __traits(isArithmetic, T))