Sema: Fix effect checking issues with 'async let' and string interpolation

Author: slavapestov

lib/Sema/ConstraintSystem.cpp

@@ -2497,10 +2497,14 @@ FunctionType::ExtInfo ConstraintSystem::closureEffects(ClosureExpr *expr) {
 
     bool walkToDeclPre(Decl *decl) override {
       // Do not walk into function or type declarations.
-      if (!isa<PatternBindingDecl>(decl))
-        return false;
+      if (auto *patternBinding = dyn_cast<PatternBindingDecl>(decl)) {
+        if (patternBinding->isAsyncLet())
+          FoundAsync = true;
 
-      return true;
+        return true;
+      }
+
+      return false;
     }
 
     std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override { 

lib/Sema/TypeCheckEffects.cpp

@@ -1153,17 +1153,14 @@ class ApplyClassifier {
       return ShouldNotRecurse;
     }
     ShouldRecurse_t checkAsyncLet(PatternBindingDecl *patternBinding) {
-      // FIXME
-      llvm_unreachable("Test me");
-      // return ShouldRecurse;
+      AsyncKind = ConditionalEffectKind::Always;
+      return ShouldRecurse;
     }
     ShouldRecurse_t checkThrow(ThrowStmt *E) {
       return ShouldRecurse;
     }
     ShouldRecurse_t checkInterpolatedStringLiteral(InterpolatedStringLiteralExpr *E) {
-      // FIXME
-      llvm_unreachable("Test me");
-      //return ShouldRecurse;
+      return ShouldRecurse;
     }
 
     ShouldRecurse_t checkIfConfig(IfConfigDecl *D) {

test/Concurrency/reasync.swift

@@ -128,3 +128,22 @@ func invalidReasyncBody(_: () async -> ()) reasync {
 func validReasyncBody(_ fn: () async -> ()) reasync {
   await fn()
 }
+
+//// String interpolation
+
+func reasyncWithAutoclosure2(_: @autoclosure () async -> String) reasync {}
+
+func callReasyncWithAutoclosure3() {
+  let world = 123
+  reasyncWithAutoclosure2("Hello \(world)")
+}
+
+//// async let
+
+func callReasyncWithAutoclosure4(_: () async -> ()) reasync {
+  await reasyncFunction {
+    async let x = 123
+
+    _ = await x
+  }
+}