[SIL] Replace a use of getInput() in classifyDynamicCast.

Use getParams() instead.

Author: rudkx

include/swift/AST/Types.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -2861,6 +2861,9 @@ class AnyFunctionType : public TypeBase {
   static bool equalParams(ArrayRef<AnyFunctionType::Param> a,
                           ArrayRef<AnyFunctionType::Param> b);
 
+  /// \brief Given two arrays of parameters determine if they are equal.
+  static bool equalParams(CanParamArrayRef a, CanParamArrayRef b);
+
   Type getInput() const { return Input; }
   Type getResult() const { return Output; }
   ArrayRef<AnyFunctionType::Param> getParams() const;

lib/AST/ASTContext.cpp

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -3608,6 +3608,18 @@ bool AnyFunctionType::equalParams(ArrayRef<AnyFunctionType::Param> a,
   return true;
 }
 
+bool AnyFunctionType::equalParams(CanParamArrayRef a, CanParamArrayRef b) {
+  if (a.size() != b.size())
+    return false;
+
+  for (unsigned i = 0, n = a.size(); i != n; ++i) {
+    if (a[i] != b[i])
+      return false;
+  }
+
+  return true;
+}
+
 FunctionType *FunctionType::get(ArrayRef<AnyFunctionType::Param> params,
                                 Type result, const ExtInfo &info,
                                 bool canonicalVararg) {

lib/SIL/DynamicCasts.cpp

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -485,9 +485,10 @@ swift::classifyDynamicCast(ModuleDecl *M,
       if (targetFunction->getRepresentation()
             != sourceFunction->getRepresentation())
         return DynamicCastFeasibility::WillFail;
-      
-      if (sourceFunction.getInput() == targetFunction.getInput()
-          && sourceFunction.getResult() == targetFunction.getResult())
+
+      if (AnyFunctionType::equalParams(sourceFunction.getParams(),
+                                       targetFunction.getParams()) &&
+          sourceFunction.getResult() == targetFunction.getResult())
         return DynamicCastFeasibility::WillSucceed;
 
       return DynamicCastFeasibility::WillFail;