Explain missing error in test

Author: oli-obk

src/test/ui/consts/const-eval/mod-static-with-const-fn.rs

@@ -27,6 +27,9 @@ fn foo() {}
 
 static BAR: () = unsafe {
     *FOO.0.get() = 5;
+    // we do not error on the above access, because that is not detectable statically. Instead,
+    // const evaluation will error when trying to evaluate it. Due to the error below, we never even
+    // attempt to const evaluate `BAR`, so we don't see the error
 
     foo();
     //~^ ERROR calls in statics are limited to constant functions, tuple structs and tuple variants

src/test/ui/consts/const-eval/mod-static-with-const-fn.stderr

@@ -1,5 +1,5 @@
 error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
-  --> $DIR/mod-static-with-const-fn.rs:31:5
+  --> $DIR/mod-static-with-const-fn.rs:34:5
    |
 LL |     foo();
    |     ^^^^^