[test] Add a lazy local test case

This hit an assertion I was trying to add to make
sure we don't try to recursively type-check when
type-checking a closure. Currently we can end up
type-checking the initializer for `x` while generating
constraints for the closure due to the fact that we
eagerly compute the interface type for the backing
lazy storage var. We ought to make that computation
lazy, but in the mean time, add this test case.

Author: hamishknight

test/SILGen/lazy_locals.swift

@@ -43,3 +43,11 @@ func lazyLocalWithNestedClosure() {
     return 3
   }()
 }
+
+func lazyLocalInClosure() {
+  // Make sure we can type-check.
+  _ = {
+    lazy var x = 0
+    return x
+  }
+}

test/expr/closure/closures.swift

@@ -1792,3 +1792,15 @@ class rdar129475277 {
     }
   }
 }
+
+class TestLazyLocal {
+  func bar() -> Int { 0 }
+  func foo() {
+    _ = { // expected-note {{capture 'self' explicitly to enable implicit 'self' in this closure}}
+      lazy var x = bar()
+      // expected-error@-1 {{call to method 'bar' in closure requires explicit use of 'self' to make capture semantics explicit}}
+      // expected-note@-2 {{reference 'self.' explicitly}}
+      return x
+    }
+  }
+}