fix Issue 9891 - Ability to modify immutable using default value of r…

…ef/out parameter
dlang · Sep 8, 2015 · 6b091dc · 6b091dc
1 parent f630e99
commit 6b091dc
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Showing 2 changed files with 37 additions and 3 deletions.
diff --git a/src/mtype.d b/src/mtype.d
@@ -5915,9 +5915,17 @@ public:
                 if (fparam.defaultArg)
                 {
                     Expression e = fparam.defaultArg;
-                    Initializer _init = new ExpInitializer(e.loc, e);
-                    _init = _init.semantic(argsc, fparam.type, INITnointerpret);
-                    e = _init.toExpression();
+                    if (fparam.storageClass & (STCref | STCout))
+                    {
+                        e = e.semantic(argsc);
+                        e = resolveProperties(argsc, e);
+                    }
+                    else
+                    {
+                        Initializer iz = new ExpInitializer(e.loc, e);
+                        iz = iz.semantic(argsc, fparam.type, INITnointerpret);
+                        e = iz.toExpression();
+                    }
                     if (e.op == TOKfunction) // see Bugzilla 4820
                     {
                         FuncExp fe = cast(FuncExp)e;

diff --git a/test/fail_compilation/fail9891.d b/test/fail_compilation/fail9891.d
@@ -0,0 +1,26 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/fail9891.d(13): Error: cast(int)i is not an lvalue
+fail_compilation/fail9891.d(18): Error: cast(int)i is not an lvalue
+fail_compilation/fail9891.d(23): Error: prop() is not an lvalue
+---
+*/
+
+immutable int i;
+int prop() { return 0; }
+
+void f1(ref int n = i)
+{
+    ++n;
+}
+
+void f2(out int n = i)
+{
+    ++n;
+}
+
+void f3(ref int n = prop)
+{
+    ++n;
+}