[Property Wrappers] Avoid creating an unnecessary property wrapper generator

function for default-initialized local and static wrapped properties.

Author: hborla

lib/Sema/TypeCheckStorage.cpp

@@ -2876,10 +2876,16 @@ PropertyWrapperInitializerInfoRequest::evaluate(Evaluator &evaluator,
       if (!parentPBD->isInitialized(patternNumber) && wrapperInfo.defaultInit) {
         // FIXME: Record this expression somewhere so that DI can perform the
         // initialization itself.
-        Expr *initializer = nullptr;
-        typeCheckSynthesizedWrapperInitializer(var, initializer);
-        pbd->setInit(0, initializer);
+        Expr *defaultInit = nullptr;
+        typeCheckSynthesizedWrapperInitializer(var, defaultInit);
+        pbd->setInit(0, defaultInit);
         pbd->setInitializerChecked(0);
+
+        // If a static, global, or local wrapped property has a default
+        // initializer, this is the only initializer that will be used.
+        if (var->isStatic() || !dc->isTypeContext()) {
+          initializer = defaultInit;
+        }
       } else if (var->hasObservers() && !dc->isTypeContext()) {
         var->diagnose(diag::observingprop_requires_initializer);
       }

test/SILGen/property_wrapper_local.swift

@@ -206,6 +206,12 @@ struct DefaultInit {
   }
 }
 
+@propertyWrapper
+struct DefaultWrappedValue {
+  // CHECK-LABEL: sil hidden [ossa] @$s22property_wrapper_local19DefaultWrappedValueVACycfC : $@convention(method) (@thin DefaultWrappedValue.Type) -> DefaultWrappedValue
+  var wrappedValue: Int = 10
+}
+
 // CHECK-LABEL: sil hidden [ossa] @$s22property_wrapper_local20testLocalDefaultInityyF : $@convention(thin) () -> ()
 func testLocalDefaultInit() {
   // CHECK: function_ref @$s22property_wrapper_local11DefaultInitVACycfC : $@convention(method) (@thin DefaultInit.Type) -> DefaultInit
@@ -216,4 +222,7 @@ func testLocalDefaultInit() {
 
   // CHECK: function_ref @$s22property_wrapper_local11DefaultInitVACycfC : $@convention(method) (@thin DefaultInit.Type) -> DefaultInit
   @DefaultInit() var y: Int
+
+  // CHECK: function_ref @$s22property_wrapper_local19DefaultWrappedValueVACycfC : $@convention(method) (@thin DefaultWrappedValue.Type) -> DefaultWrappedValue
+  @DefaultWrappedValue var w: Int
 }