Issue 10018 - Add VRP support for const/immutable variables

dlang · Jun 28, 2014 · 45a26d5 · 45a26d5
1 parent db18e36
commit 45a26d5
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/src/cast.c b/src/cast.c
@@ -3405,11 +3405,20 @@ IntRange getIntRange(Expression *e)
             range = IntRange(ir1.imin >> ir2.imax, ir1.imax >> ir2.imin).cast(e->type);
         }
 
+        void visit(AssignExp *e)
+        {
+            range = getIntRange(e->e2).cast(e->type);
+        }
+
         void visit(VarExp *e)
         {
+            Expression *ie;
             VarDeclaration* vd = e->var->isVarDeclaration();
             if (vd && vd->range)
-                range = *vd->range;
+                range = vd->range->cast(e->type);
+            else if (vd && vd->init && !vd->type->isMutable() &&
+                (ie = vd->getConstInitializer()))
+                ie->accept(this);
             else
                 visit((Expression *)e);
         }

diff --git a/test/compilable/testVRP.d b/test/compilable/testVRP.d
@@ -306,3 +306,16 @@ void test9617a()
         }
     }
 }
+
+void test10018(ubyte value)
+{
+    const int c = value;
+    ubyte b = c;
+    static assert(!__traits(compiles, b = c - 1));
+    static assert(!__traits(compiles, b = c + 1));
+    immutable int i = value;
+    b = i;
+    static assert(!__traits(compiles, b = i - 1));
+    static assert(!__traits(compiles, b = i + 1));
+}
+