fix Issue 14238 - DIP25: escape checks can be circumvented with delegate

dlang · Nov 1, 2016 · 7c3e47a · 7c3e47a
1 parent eb4d6fe
commit 7c3e47a
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Showing 2 changed files with 47 additions and 0 deletions.
diff --git a/src/escape.d b/src/escape.d
@@ -742,6 +742,17 @@ private void escapeByRef(Expression e, VarDeclarations* byref, VarDeclarations *
                             Parameter p = Parameter.getNth(tf.parameters, i - j);
                             if ((p.storageClass & (STCout | STCref)) && (p.storageClass & STCreturn))
                                 arg.accept(this);
+                            else if ((p.storageClass & STCscope) && (p.storageClass & STCreturn))
+                            {
+                                if (arg.op == TOKdelegate)
+                                {
+                                    DelegateExp de = cast(DelegateExp)arg;
+                                    if (de.func.isNested())
+                                        byexp.push(de);
+                                }
+                                else
+                                    escapeByValue(arg, byref, byvalue, byexp);
+                            }
                         }
                     }
                 }
@@ -752,6 +763,11 @@ private void escapeByRef(Expression e, VarDeclarations* byref, VarDeclarations *
                     if (dve.var.storage_class & STCreturn || tf.isreturn)
                         dve.e1.accept(this);
                 }
+                // If it's a delegate, check it too
+                if (e.e1.op == TOKvar && t1.ty == Tdelegate)
+                {
+                    escapeByValue(e.e1, byref, byvalue, byexp);
+                }
             }
             else
                 byexp.push(e);
@@ -762,3 +778,4 @@ private void escapeByRef(Expression e, VarDeclarations* byref, VarDeclarations *
     e.accept(v);
 }
 
+
diff --git a/test/fail_compilation/test14238.d b/test/fail_compilation/test14238.d
@@ -0,0 +1,30 @@
+/* REQUIRED_ARGS: -dip25
+   PERMUTE_ARGS:
+   TEST_OUTPUT:
+---
+fail_compilation/test14238.d(21): Error: scope variable fn may not be returned
+fail_compilation/test14238.d(29): Error: escaping reference to stack allocated value returned by &baz
+---
+*/
+// https://issues.dlang.org/show_bug.cgi?id=14238
+
+@safe:
+
+alias Fn = ref int delegate();
+
+ref int foo(return scope Fn fn)
+{
+    return fn(); // Ok
+}
+
+ref int foo2(scope Fn fn) {
+    return fn(); // Error
+}
+
+ref int bar() {
+    int x;
+    ref int baz() {
+            return x;
+    }
+    return foo(&baz);
+}