Merge pull request #85183 from slavapestov/fix-issue-85034

Sema: Don't coerce subexpression of 'try' to rvalue

Author: slavapestov

lib/Sema/CSApply.cpp

@@ -3752,7 +3752,11 @@ namespace {
       return expr;
     }
 
-    Expr *visitAnyTryExpr(AnyTryExpr *expr) {
+    Expr *visitTryExpr(TryExpr *expr) {
+      return simplifyExprType(expr);
+    }
+
+    Expr *visitForceTryExpr(ForceTryExpr *expr) {
       auto *subExpr = expr->getSubExpr();
       auto type = simplifyType(cs.getType(subExpr));
 

lib/Sema/CSGen.cpp

@@ -2060,10 +2060,20 @@ namespace {
       return valueTy;
     }
 
-    Type visitAnyTryExpr(AnyTryExpr *expr) {
+    Type visitTryExpr(AnyTryExpr *expr) {
       return CS.getType(expr->getSubExpr());
     }
 
+    Type visitForceTryExpr(AnyTryExpr *expr) {
+      auto valueTy = CS.createTypeVariable(CS.getConstraintLocator(expr),
+                                           TVO_PrefersSubtypeBinding |
+                                               TVO_CanBindToNoEscape);
+      CS.addConstraint(ConstraintKind::Equal, valueTy,
+                       CS.getType(expr->getSubExpr()),
+                       CS.getConstraintLocator(expr));
+      return valueTy;
+    }
+
     Type visitOptionalTryExpr(OptionalTryExpr *expr) {
       auto valueTy = CS.createTypeVariable(CS.getConstraintLocator(expr),
                                            TVO_PrefersSubtypeBinding |

lib/Sema/TypeCheckConstraints.cpp

@@ -1192,10 +1192,7 @@ TypeChecker::coerceToRValue(ASTContext &Context, Expr *expr,
                             llvm::function_ref<Type(Expr *)> getType,
                             llvm::function_ref<void(Expr *, Type)> setType) {
   Type exprTy = getType(expr);
-
-  // If expr has no type, just assume it's the right expr.
-  if (!exprTy)
-    return expr;
+  ASSERT(exprTy);
 
   // If the type is already materializable, then we're already done.
   if (!exprTy->hasLValueType())

lib/Sema/TypeCheckStmt.cpp

@@ -1702,10 +1702,11 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
     // Type-check the subject expression.
     Expr *subjectExpr = switchStmt->getSubjectExpr();
     auto resultTy = TypeChecker::typeCheckExpression(subjectExpr, DC);
+
     auto limitExhaustivityChecks = !resultTy;
-    if (Expr *newSubjectExpr =
-            TypeChecker::coerceToRValue(getASTContext(), subjectExpr))
-      subjectExpr = newSubjectExpr;
+    if (resultTy)
+      subjectExpr = TypeChecker::coerceToRValue(getASTContext(), subjectExpr);
+
     switchStmt->setSubjectExpr(subjectExpr);
     Type subjectType = switchStmt->getSubjectExpr()->getType();
 

validation-test/Sema/type_checker_crashers_fixed/rdar78102266.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend %s -typecheck
+// RUN: %target-swift-emit-silgen %s
 
 struct Info {
 }

validation-test/compiler_crashers_fixed/issue-85034.swift

@@ -0,0 +1,12 @@
+// RUN: %target-typecheck-verify-swift
+// RUN: %target-swift-emit-silgen %s
+
+class C {
+  var x = 0
+}
+
+do {
+  let x = C()
+  let _ = (0, try x.x)  // expected-warning {{no calls to throwing functions occur within 'try' expression}}
+  let _ = (0, try! x.x)  // expected-warning {{no calls to throwing functions occur within 'try' expression}}
+}