[test] coverage for global effectful props

Author: kavon

test/decl/var/effectful_properties_global.swift

@@ -0,0 +1,41 @@
+// RUN: %target-typecheck-verify-swift -enable-experimental-concurrency
+
+var intAsyncProp : Int {
+  get async { 0 }
+}
+
+var intThrowsProp : Int { // expected-note 2 {{var declared here}}
+  get throws { 0 }
+}
+
+var asyncThrowsProp : Int {
+  // expected-warning@+1 {{reference to var 'intThrowsProp' is not concurrency-safe because it involves shared mutable state}}
+  get async throws { try await intAsyncProp + intThrowsProp }
+}
+
+func hello() async {
+  // expected-warning@+1 {{reference to var 'intThrowsProp' is not concurrency-safe because it involves shared mutable state}}
+  _ = intThrowsProp // expected-error{{property access can throw, but it is not marked with 'try' and the error is not handled}}
+
+  _ = intAsyncProp // expected-error{{property access is 'async' but is not marked with 'await'}}
+}
+
+class C {
+  var counter : Int = 0
+}
+
+var refTypeThrowsProp : C { // expected-note {{var declared here}}
+  get throws { return C() }
+}
+
+var refTypeAsyncProp : C {
+  get async { return C() }
+}
+
+func salam() async {
+  // expected-warning@+1 {{reference to var 'refTypeThrowsProp' is not concurrency-safe because it involves shared mutable state}}
+  _ = refTypeThrowsProp // expected-error{{property access can throw, but it is not marked with 'try' and the error is not handled}}
+
+
+  _ = refTypeAsyncProp // expected-error {{property access is 'async' but is not marked with 'await'}}
+}