[TypeChecker] NFC: Add a couple of test-cases for .callAsFunction

Make sure that trailing closure(s) are correctly matched to injected
`.callAsFunction` when necessary i.e. constructor doesn't attempt
trailing closures but `.callAsFunction` does.

Author: xedin

test/Constraints/callAsFunction.swift

@@ -0,0 +1,31 @@
+// RUN: %target-typecheck-verify-swift
+
+// rdar://83717297
+//
+// Make sure that trailing closures are matches to the `callAsFunction`
+// when used in the same expression as `.init` of a callable type.
+
+protocol View {}
+struct EmptyView: View {}
+
+struct MyLayout {
+  func callAsFunction<V: View>(content: () -> V) -> MyLayout { .init() }
+  func callAsFunction<V: View>(answer: () -> Int,
+                               content: () -> V) -> MyLayout { .init() }
+}
+
+struct Test {
+  var body1: MyLayout {
+    MyLayout() {
+      EmptyView() // Ok
+    }
+  }
+
+  var body2: MyLayout {
+    MyLayout() {
+      42
+    } content: {
+      EmptyView() // Ok
+    }
+  }
+}