fix Issue 12909 - [AA] Function is incorrectly inferred as strongly p…

…ure for associative array with key of non-mutable array or pointer as argument
dlang · Jun 14, 2014 · 20feb28 · 20feb28
1 parent f4cb15c
commit 20feb28
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Showing 3 changed files with 50 additions and 17 deletions.
diff --git a/src/mtype.c b/src/mtype.c
@@ -5805,12 +5805,26 @@ void TypeFunction::purityLevel()
             break;
         }
 
-        t = t->toBasetype();
+        t = t->baseElemOf();
         if (!t->hasPointers())
             continue;
         if (t->mod & MODimmutable)
             continue;
 
+        /* Accept immutable(T)[] and immutable(T)* as being strongly pure
+         */
+        if (t->ty == Tarray || t->ty == Tpointer)
+        {
+            Type *tn = t->nextOf()->toBasetype();
+            if (tn->mod & MODimmutable)
+                continue;
+            if (tn->mod & (MODconst | MODwild))
+            {
+                tf->purity = PUREconst;
+                continue;
+            }
+        }
+
         /* The rest of this is too strict; fix later.
          * For example, the only pointer members of a struct may be immutable,
          * which would maintain strong purity.
@@ -5820,22 +5834,7 @@ void TypeFunction::purityLevel()
             tf->purity = PUREconst;
             continue;
         }
-        if (Type *tn = t->nextOf())
-        {
-            tn = tn->toBasetype();
-            if (tn->ty == Tpointer || tn->ty == Tarray)
-            {
-                /* Accept immutable(T)* and immutable(T)[] as being strongly pure
-                 */
-                if (tn->mod & MODimmutable)
-                    continue;
-                if (tn->mod & (MODconst | MODwild))
-                {
-                    tf->purity = PUREconst;
-                    continue;
-                }
-            }
-        }
+
         /* Should catch delegates and function pointers, and fold in their purity
          */
 

diff --git a/test/compilable/warn3882.d b/test/compilable/warn3882.d
@@ -46,3 +46,17 @@ struct K12760
     }
 }
 
+/******************************************/
+// 12909
+
+int f12909(immutable(int[])[int] aa) pure nothrow
+{
+    aa[0] = [];
+    return 0;
+}
+
+void test12909()
+{
+    immutable(int[])[int] aa;
+    f12909(aa);
+}
diff --git a/test/fail_compilation/fail3882.d b/test/fail_compilation/fail3882.d
@@ -26,3 +26,23 @@ void main()
     auto fp = &strictlyPure!int;
     fp(x);
 }
+
+/******************************************/
+// bugfix in TypeFunction::purityLevel
+
+/*
+TEST_OUTPUT:
+---
+fail_compilation/fail3882.d(46): Warning: calling fail3882.f1 without side effects discards return value of type int, prepend a cast(void) if intentional
+fail_compilation/fail3882.d(47): Warning: calling fail3882.f2 without side effects discards return value of type int, prepend a cast(void) if intentional
+---
+*/
+
+nothrow pure int f1(immutable(int)[] a) { return 0; }
+nothrow pure int f2(immutable(int)*  p) { return 0; }
+
+void test_bug()
+{
+    f1([]);
+    f2(null);
+}