Merge pull request #7708 from CodaFi/fully-reloaded

[SR-3896] Add missing r-value coercion for type(of:)'s argument

Author: slavapestov

lib/Sema/CSApply.cpp

@@ -6321,6 +6321,7 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
         auto arg = apply->getArg();
         if (auto tuple = dyn_cast<TupleExpr>(arg))
           arg = tuple->getElements()[0];
+        arg = cs.coerceToRValue(arg);
         auto replacement = new (tc.Context)
           DynamicTypeExpr(apply->getFn()->getLoc(),
                           apply->getArg()->getStartLoc(),

test/Compatibility/lvalue_typeof.swift

@@ -0,0 +1,6 @@
+// RUN: %target-typecheck-verify-swift -swift-version 4
+
+// Make sure an r-value coercion is performed on the argument in Swift 4 mode.
+var x: Int = 1
+_ = type(of: x)
+