[SE-0111] Suppress the printing of argument labels in function types.

Argument labels still persist on the function types of declarations,
so suppress them entirely when printing function types.

Author: DougGregor

lib/AST/ASTPrinter.cpp

@@ -3821,14 +3821,28 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 
     printFunctionExtInfo(T->getExtInfo());
 
+    // If we're stripping argument labels from types, do it when printing.
+    Type inputType = T->getInput();
+    if (inputType->getASTContext().LangOpts.SuppressArgumentLabelsInTypes) {
+      if (auto tupleTy = dyn_cast<TupleType>(inputType.getPointer())) {
+        SmallVector<TupleTypeElt, 4> elements;
+        elements.reserve(tupleTy->getNumElements());
+        for (const auto &elt : tupleTy->getElements()) {
+          elements.push_back(TupleTypeElt(elt.getType(), Identifier(),
+                                          elt.isVararg()));
+        }
+        inputType = TupleType::get(elements, inputType->getASTContext());
+      }
+    }
+
     bool needsParens =
-      !isa<ParenType>(T->getInput().getPointer()) &&
-      !T->getInput()->is<TupleType>();
+      !isa<ParenType>(inputType.getPointer()) &&
+      !inputType->is<TupleType>();
 
     if (needsParens)
       Printer << "(";
 
-    visit(T->getInput());
+    visit(inputType);
 
     if (needsParens)
       Printer << ")";

test/SILGen/argument_labels.swift

@@ -0,0 +1,19 @@
+// RUN: %target-swift-frontend -emit-silgen -suppress-argument-labels-in-types %s | FileCheck %s
+
+public struct X { }
+public struct Y { }
+
+public class Foo {
+  func doSomething(x: X, y: Y) { }
+  func doSomethingElse(x: X) { }
+}
+
+// CHECK-LABEL: sil hidden @_TF15argument_labels7testFoo
+func testFoo(foo: Foo, x: X, y: Y) {
+  // CHECK: class_method %0 : $Foo, #Foo.doSomething!1 : (Foo) -> (X, Y) -> ()
+  foo.doSomething(x: x, y: y)
+
+  // CHECK: class_method %0 : $Foo, #Foo.doSomethingElse!1 : (Foo) -> (X) -> ()
+  foo.doSomethingElse(x: x)
+}
+