[Omit needless words] Stop using Objective-C type parameter names as type names.

Objective-C type parameter names aren't strong enough indicators to
use for removing redundant type information. Fixes
rdar://problem/24635887.

Author: DougGregor

lib/ClangImporter/ImportType.cpp

@@ -1495,16 +1495,6 @@ OmissionTypeName ClangImporter::Implementation::getClangTypeNameForOmission(
     if (auto typedefType = dyn_cast<clang::TypedefType>(typePtr)) {
       auto name = typedefType->getDecl()->getName();
 
-      // For Objective-C type parameters, drop the "Type" suffix if
-      // present.
-      if (isa<clang::ObjCTypeParamDecl>(typedefType->getDecl())) {
-        if (camel_case::getLastWord(name) == "Type") {
-          name = name.drop_back(4);
-        }
-
-        return name;
-      }
-
       // Objective-C selector type.
       if (ctx.hasSameUnqualifiedType(type, ctx.getObjCSelType()) &&
           name == "SEL")

test/IDE/print_omit_needless_words.swift

@@ -47,8 +47,8 @@
 // CHECK-FOUNDATION: func copy(with _: Zone = nil) -> AnyObject!
 
 // Note: Objective-C type parameter names.
-// CHECK-FOUNDATION: func object(for _: Copying) -> AnyObject?
-// CHECK-FOUNDATION: func removeObject(for _: Copying)
+// CHECK-FOUNDATION: func object(forKey _: Copying) -> AnyObject?
+// CHECK-FOUNDATION: func removeObject(forKey _: Copying)
 
 // Note: Don't drop the name of the first parameter in an initializer entirely.
 // CHECK-FOUNDATION: init(array: [AnyObject])