NoOp Reference Change (#494)

Added NoOp to precondition verification for ClassicallyControlled.

Author: ScottCarda-MS

src/QsCompiler/Compiler/RewriteSteps/ClassicallyControlled.cs

@@ -2,7 +2,9 @@
 // Licensed under the MIT License.
 
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
+using Microsoft.Quantum.QsCompiler.DataTypes;
 using Microsoft.Quantum.QsCompiler.SyntaxTree;
 using Microsoft.Quantum.QsCompiler.Transformations.ClassicallyControlled;
 
@@ -30,20 +32,7 @@ public ClassicallyControlled()
 
         public bool PreconditionVerification(QsCompilation compilation)
         {
-            var controlNs = compilation.Namespaces
-                .FirstOrDefault(ns => ns.Name.Equals(BuiltIn.ClassicallyControlledNamespace));
-
-            if (controlNs == null)
-            {
-                return false;
-            }
-
-            var providedOperations = new QsNamespace[] { controlNs }
-                .Callables()
-                .Select(c => c.FullName)
-                .ToHashSet();
-            var requiredBuiltIns = new HashSet<QsQualifiedName>()
-            {
+            var classicallyControlledRequired = ImmutableHashSet.Create(
                 BuiltIn.ApplyIfZero.FullName,
                 BuiltIn.ApplyIfZeroA.FullName,
                 BuiltIn.ApplyIfZeroC.FullName,
@@ -58,9 +47,23 @@ public bool PreconditionVerification(QsCompilation compilation)
                 BuiltIn.ApplyIfElseRA.FullName,
                 BuiltIn.ApplyIfElseRC.FullName,
                 BuiltIn.ApplyIfElseRCA.FullName
-            };
+            );
 
-            return requiredBuiltIns.IsSubsetOf(providedOperations);
+            if (!CheckForRequired(compilation, BuiltIn.ClassicallyControlledNamespace, classicallyControlledRequired))
+            {
+                return false;
+            }
+
+            var cannonRequired = ImmutableHashSet.Create(
+                BuiltIn.NoOp.FullName
+            );
+
+            if (!CheckForRequired(compilation, BuiltIn.CanonNamespace, cannonRequired))
+            {
+                return false;
+            }
+
+            return true;
         }
 
         public bool Transformation(QsCompilation compilation, out QsCompilation transformed)
@@ -73,5 +76,23 @@ public bool PostconditionVerification(QsCompilation compilation)
         {
             throw new System.NotImplementedException();
         }
+
+        private bool CheckForRequired(QsCompilation compilation, NonNullable<string> namespaceName, ImmutableHashSet<QsQualifiedName> requiredBuiltIns)
+        {
+            var builtInNs = compilation.Namespaces
+                .FirstOrDefault(ns => ns.Name.Equals(namespaceName));
+
+            if (builtInNs == null)
+            {
+                return false;
+            }
+
+            var providedOperations = new QsNamespace[] { builtInNs }
+                .Callables()
+                .Select(c => c.FullName)
+                .ToImmutableHashSet();
+
+            return requiredBuiltIns.IsSubsetOf(providedOperations);
+        }
     }
 }