[Property Wrappers] Don't allow parameters with attached property wrappers

in protocol requirements.

Author: hborla

include/swift/AST/DiagnosticsSema.def

@@ -5524,9 +5524,9 @@ ERROR(property_with_wrapper_conflict_attribute,none,
 ERROR(property_wrapper_not_single_var, none,
       "property wrapper can only apply to a single variable", ())
 ERROR(property_with_wrapper_in_bad_context,none,
-      "%select{|non-static |non-static }1property %0 declared inside "
+      "%select{|non-static|non-static}1 %2 %0 declared inside "
       "%select{a protocol|an extension|an enum}1 cannot have a wrapper",
-      (Identifier, int))
+      (Identifier, int, DescriptiveDeclKind))
 ERROR(property_with_wrapper_overrides,none,
       "property %0 with attached wrapper cannot override another property",
       (Identifier))

lib/Sema/TypeCheckPropertyWrapper.cpp

@@ -455,6 +455,10 @@ AttachedPropertyWrappersRequest::evaluate(Evaluator &evaluator,
       continue;
     }
 
+    if (isa<ParamDecl>(var) && isa<AbstractFunctionDecl>(dc)) {
+      dc = dc->getAsDecl()->getDeclContext();
+    }
+
     // A property with a wrapper cannot be declared in a protocol, enum, or
     // an extension.
     if (isa<ProtocolDecl>(dc) ||
@@ -468,7 +472,7 @@ AttachedPropertyWrappersRequest::evaluate(Evaluator &evaluator,
       else
         whichKind = 2;
       var->diagnose(diag::property_with_wrapper_in_bad_context,
-                    var->getName(), whichKind)
+                    var->getName(), whichKind, var->getDescriptiveKind())
         .highlight(attr->getRange());
 
       continue;

test/Sema/property_wrapper_parameter_invalid.swift

@@ -83,3 +83,8 @@ func testInvalidArgLabel() {
   // expected-error@+1 {{cannot use property wrapper projection argument; parameter does not have an attached property wrapper}}
   noWrappers($argLabel: 10)
 }
+
+protocol P {
+  // expected-error@+1 {{parameter 'arg' declared inside a protocol cannot have a wrapper}}
+  func requirement(@Wrapper arg: Int)
+}