Add RequiresCapability attribute

src/Simulation/QsharpCore/Core.qs

@@ -22,15 +22,14 @@ namespace Microsoft.Quantum.Core {
     /// # Summary
     /// Compiler-recognized attribute used to mark a type or callable as deprecated.
     /// 
-    /// # Input
+    /// # Named Items
     /// ## NewName
     /// The full name of the type or callable to use instead. 
     /// Is set to the empty String if a type or callable has been deprecated without substitution. 
     ///
     @Attribute()
     newtype Deprecated = (NewName : String);
 
-
     /// # Summary
     /// Returns a default instance of the specified type. 
     ///
@@ -136,5 +135,3 @@ namespace Microsoft.Quantum.Core {
     }
 
 }
-
-

src/Simulation/QsharpCore/Intrinsic.qs

@@ -4,6 +4,7 @@
 namespace Microsoft.Quantum.Intrinsic {
     open Microsoft.Quantum.Math;
     open Microsoft.Quantum.Convert;
+    open Microsoft.Quantum.Targeting;
 
     @Deprecated("Microsoft.Quantum.Random.DrawCategorical")
     operation Random (probs : Double[]) : Int {
@@ -657,24 +658,26 @@ namespace Microsoft.Quantum.Intrinsic {
     operation M (qubit : Qubit) : Result {
         return Measure([PauliZ], [qubit]);
     }
-    
-    
+
+
     /// # Summary
     /// Given a single qubit, measures it and ensures it is in the |0⟩ state
     /// such that it can be safely released.
     ///
     /// # Input
-    /// ## qubit
+    /// ## target
     /// The qubit whose state is to be reset to $\ket{0}$.
+    @RequiresCapability(
+        "BasicQuantumFunctionality",
+        "Reset is replaced by a supported implementation on all execution targets."
+    )
     operation Reset (target : Qubit) : Unit {
-
-        if (M(target) == One)
-        {
+        if (M(target) == One) {
             X(target);
         }
     }
-    
-    
+
+
     /// # Summary
     /// Given an array of qubits, measure them and ensure they are in the |0⟩ state
     /// such that they can be safely released.
@@ -683,12 +686,8 @@ namespace Microsoft.Quantum.Intrinsic {
     /// ## qubits
     /// An array of qubits whose states are to be reset to $\ket{0}$.
     operation ResetAll (qubits : Qubit[]) : Unit {
-
         for (qubit in qubits) {
             Reset(qubit);
         }
     }
-
 }
-
-

src/Simulation/QsharpCore/Targeting.qs

@@ -0,0 +1,39 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+/// # Summary
+/// This namespace provides functionality for targeting specific quantum processors.
+namespace Microsoft.Quantum.Targeting {
+    /// # Summary
+    /// Compiler-recognized attribute used to mark a callable with the runtime capabilities it
+    /// requires.
+    ///
+    /// # Named Items
+    /// ## Level
+    /// The name of the runtime capability level required by the callable.
+    ///
+    /// ## Reason
+    /// A description of why the callable requires this runtime capability.
+    /// 
+    /// # Remarks
+    /// This attribute is automatically added to callables by the compiler, unless an instance of
+    /// this attribute already exists on the callable. It should not be used except in rare cases
+    /// where the compiler does not infer the required capability correctly.
+    ///
+    /// Below is the list of capability level names, in order of increasing capabilities or
+    /// decreasing restrictions:
+    ///
+    /// ## `"BasicQuantumFunctionality"`
+    /// Measurement results cannot be compared for equality.
+    ///
+    /// ## `"BasicMeasurementFeedback"`
+    /// Measurement results can be compared for equality only in if-statement conditional
+    /// expressions in operations. The block of an if-statement that depends on a result cannot
+    /// contain set statements for mutable variables declared outside the block, or return
+    /// statements.
+    ///
+    /// ## `"FullComputation"`
+    /// No runtime restrictions. Any Q# program can be executed.
+    @Attribute()
+    newtype RequiresCapability = (Level : String, Reason : String);
+}