[CSGen] Fix compiler crash when property wrapper applied to a param lacks wrappedValue initializer

Author: janbaig

lib/Sema/CSGen.cpp

@@ -5060,18 +5060,35 @@ ConstraintSystem::applyPropertyWrapperToParameter(
     anchor = apply->getFn();
   }
 
-  if (argLabel.hasDollarPrefix() && (!param || !param->hasExternalPropertyWrapper())) {
+  auto recordPropertyWrapperFix = [&](ConstraintFix *fix) -> TypeMatchResult {
     if (!shouldAttemptFixes())
       return getTypeMatchFailure(locator);
 
     recordAnyTypeVarAsPotentialHole(paramType);
 
-    auto *loc = getConstraintLocator(locator);
-    auto *fix = RemoveProjectedValueArgument::create(*this, wrapperType, param, loc);
     if (recordFix(fix))
       return getTypeMatchFailure(locator);
 
     return getTypeMatchSuccess();
+  };
+
+  // Incorrect use of projected value argument
+  if (argLabel.hasDollarPrefix() &&
+      (!param || !param->hasExternalPropertyWrapper())) {
+    auto *loc = getConstraintLocator(locator);
+    auto *fix =
+        RemoveProjectedValueArgument::create(*this, wrapperType, param, loc);
+    return recordPropertyWrapperFix(fix);
+  }
+
+  // Missing wrapped value initializer
+  auto wrapperInfo = param->getAttachedPropertyWrapperTypeInfo(0);
+  if (!argLabel.hasDollarPrefix() && !wrapperInfo.wrappedValueInit &&
+      param->hasExternalPropertyWrapper()) {
+    auto *loc = getConstraintLocator(locator);
+    auto *fix = UsePropertyWrapper::create(
+        *this, param, /*usingProjection=*/true, paramType, wrapperType, loc);
+    return recordPropertyWrapperFix(fix);
   }
 
   if (argLabel.hasDollarPrefix()) {

validation-test/Sema/type_checker_crashers_fixed/issue-65500.swift

@@ -0,0 +1,16 @@
+//  RUN: %target-typecheck-verify-swift
+
+// https://github.com/swiftlang/swift/issues/65500
+
+@propertyWrapper
+struct Wrapper { 
+  var wrappedValue: Bool { true }
+  init(wrappedValue: Bool, er: Void) {}
+
+  var projectedValue: Bool { true }
+  init(projectedValue: Bool) {}
+}
+
+func test(@Wrapper x: Bool) {} 
+test(x: false) 
+// expected-error@-1 {{cannot convert value 'x' of type 'Bool' to expected type 'Wrapper', use wrapper instead}}{{9-9=$}}