fix Issue 15191 - DIP25: Taking address of ref return is not type che…

…cked soundly

src/expression.d

@@ -10662,6 +10662,19 @@ extern (C++) final class AddrExp : UnaExp
                 }
             }
         }
+        else if (e1.op == TOKcall)
+        {
+            CallExp ce = cast(CallExp)e1;
+            if (ce.e1.type.ty == Tfunction)
+            {
+                TypeFunction tf = cast(TypeFunction)ce.e1.type;
+                if (tf.isref && sc.func && !sc.intypeof && sc.func.setUnsafe())
+                {
+                    error("cannot take address of ref return of %s() in @safe function %s",
+                        ce.e1.toChars(), sc.func.toChars());
+                }
+            }
+        }
         else if (wasCond)
         {
             /* a ? b : c was transformed to *(a ? &b : &c), but we still

test/fail_compilation/test15191.d

@@ -0,0 +1,18 @@
+/* TEST_OUTPUT:
+---
+fail_compilation/test15191.d(17): Error: cannot take address of ref return of foo() in @safe function bar
+---
+*/
+
+
+// https://issues.dlang.org/show_bug.cgi?id=15191
+
+ref int foo(return ref int s)@safe
+{
+    return s;
+}
+
+int* bar(return ref int s) @safe
+{
+    return &foo(s);
+}