Make nested expr work, convert test to executable

Author: MaxDesiatov

lib/Sema/CSSyntacticElement.cpp

@@ -1292,8 +1292,12 @@ class SyntacticElementConstraintGenerator
 
     // First check to make sure the ThenStmt is in a valid position.
     SmallVector<ThenStmt *, 4> validThenStmts;
-    if (auto SVE = context.getAsSingleValueStmtExpr())
+    if (auto SVE = context.getAsSingleValueStmtExpr()) {
       (void)SVE.get()->getThenStmts(validThenStmts);
+      if (SVE.get()->getStmtKind() == SingleValueStmtExpr::Kind::For) {
+        contextInfo = std::nullopt;
+      }
+    }
 
     if (!llvm::is_contained(validThenStmts, thenStmt)) {
       auto *thenLoc = cs.getConstraintLocator(thenStmt);
@@ -2251,7 +2255,9 @@ class SyntacticElementSolutionApplication
     // not the branch result type. This is necessary as there may be
     // an additional conversion required for the branch.
     auto target = solution.getTargetFor(thenStmt->getResult());
-    target->setExprConversionType(ty);
+    if (SVE.get()->getStmtKind() != SingleValueStmtExpr::Kind::For) {
+      target->setExprConversionType(ty);
+    }
 
     auto *resultExpr = thenStmt->getResult();
     if (auto newResultTarget = rewriter.rewriteTarget(*target))

lib/Sema/PreCheckTarget.cpp

@@ -1742,10 +1742,14 @@ void PreCheckTarget::transformForExpression(SingleValueStmtExpr *SVE) {
     if (auto stmt = result.dyn_cast<Stmt *>()) {
       if (auto *then = dyn_cast<ThenStmt>(stmt)) {
         auto *declRefExpr = new(astCtx) DeclRefExpr(varDecl, DeclNameLoc(), true);
-        auto *dotExpr = new(astCtx) UnresolvedDotExpr(declRefExpr, sveLoc, DeclNameRef(DeclBaseName(astCtx.Id_append)), DeclNameLoc(), true);
+        auto *dotExpr = new(astCtx) UnresolvedDotExpr(declRefExpr,
+                                                      SourceLoc(),
+                                                      DeclNameRef(DeclBaseName(astCtx.Id_append)),
+                                                      DeclNameLoc(),
+                                                      true);
         auto *argumentList = ArgumentList::createImplicit(astCtx, { Argument::unlabeled(then->getResult()) });
         auto *callExpr = CallExpr::createImplicit(astCtx, dotExpr, argumentList);
-        result = callExpr;
+        then->setResult(callExpr);
       }
     }
   }

test/Sema/for-expr.swift

@@ -0,0 +1,13 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature ForExpressions) | %FileCheck %s
+
+func f() -> String {
+  for (i, x) in "hello".enumerated() {
+    if i % 2 == 0 {
+      x.uppercased()
+    } else  {
+      "*skip*"
+
+    }
+  }
+}
+print(f()) // CHECK: H*skip*L*skip*O