[CSClosure] Add support for projected/wrapper values

To support referencing projected and/or wrapped var
in a closure solver needs to lookup a type of their
originator and based on the wrapper type compute and
assign types to projection and/or wrapper.

Resolves: #59295
Resolves: rdar://94506352

Author: xedin

lib/Sema/CSClosure.cpp

@@ -96,6 +96,29 @@ class TypeVariableRefFinder : public ASTWalker {
       if (!var)
         return {true, expr};
 
+      if (auto *wrappedVar = var->getOriginalWrappedProperty()) {
+        auto outermostWrapperAttr =
+            wrappedVar->getAttachedPropertyWrappers().front();
+
+        // If the attribute doesn't have a type it could only mean
+        // that the declaration was incorrect.
+        if (!CS.hasType(outermostWrapperAttr->getTypeExpr()))
+          return {true, expr};
+
+        auto wrapperType =
+            CS.simplifyType(CS.getType(outermostWrapperAttr->getTypeExpr()));
+
+        if (var->getName().hasDollarPrefix()) {
+          // $<name> is the projected value var
+          CS.setType(var, computeProjectedValueType(wrappedVar, wrapperType));
+        } else {
+          // _<name> is the wrapper var
+          CS.setType(var, computeWrappedValueType(wrappedVar, wrapperType));
+        }
+
+        return {true, expr};
+      }
+
       // If there is no type recorded yet, let's check whether
       // it is a placeholder variable implicitly generated by the
       // compiler.

validation-test/Sema/type_checker_crashers_fixed/issue59294.swift

@@ -1,6 +1,7 @@
 // RUN: %target-typecheck-verify-swift
 
 // https://github.com/apple/swift/issues/59294
+// https://github.com/apple/swift/issues/59295
 
 @propertyWrapper
 struct WrapperValue<Value> {
@@ -25,18 +26,94 @@ struct WrapperValue<Value> {
   func printValue() {
     print(value)
   }
+
+  func returnValue() -> Value {
+    return value
+  }
 }
 
+@propertyWrapper
+struct OuterWrapper<Value> {
+  var value: Value
+  init(wrappedValue: Value) {
+    self.value = wrappedValue
+  }
+
+  var projectedValue: Self {
+    return self
+  }
+
+  var wrappedValue: Value {
+    get {
+      self.value
+    }
+    set {
+      self.value = newValue
+    }
+  }
+}
 
 class Test {
   static func test() {
     return [0, 1, 2].compactMap { _ in // expected-error {{unexpected non-void return value in void function}} expected-note {{did you mean to add a return type?}}
       @WrapperValue var value: Bool? = false
       if value != nil {
+        $value.printValue()
         return false
       }
 
       return value ?? false
     }
   }
+  static func testProjectedAndWrapperVars() {
+    func test(_: (Int) -> Bool) {}
+    func test(_: (String) -> Void) {}
+
+    test {
+      @WrapperValue var value = $0
+      if $value.returnValue() > 0 {
+        test {
+          return $value.returnValue() == $0 &&
+                 _value == $0
+        }
+      }
+      return false
+    }
+
+    test {
+      @WrapperValue var value = $0
+
+      test {
+        if _value != $0 { // Ok
+          $value.printValue()
+        }
+      }
+    }
+  }
+
+  static func testNestedWrappers() {
+    func test(_: (Bool) -> Void) {}
+    func test(_: () -> Void) {}
+
+    test {
+      if true {
+        @OuterWrapper @WrapperValue var value = $0
+        if true {
+          let _: Bool = _value == $0
+          let _: OuterWrapper<WrapperValue<Bool>> = $value
+          let _: Bool = value
+        }
+      }
+    }
+  }
+
+  static func invalidVar() {
+    _ = [0, 1, 2].compactMap {
+      @WrapperValue var value: Bool? = $0
+      // expected-error@-1 {{cannot convert value of type 'Int' to specified type 'Bool?'}}
+      if true {
+        $value.printValue()
+      }
+    }
+  }
 }