PR45083: Mark statement expressions as being dependent if they appear in

dependent contexts.

We previously assumed they were neither value- nor
instantiation-dependent under any circumstances, which would lead to
crashes and other misbehavior.

(cherry picked from commit bdad0a1b79273733df9acc1be4e992fa5d70ec56)

1 files changed, 12 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 29562615e58..63d8d7506d0 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -13908,9 +13908,8 @@ void Sema::ActOnStmtExprError() {
   PopExpressionEvaluationContext();
 }
 
-ExprResult
-Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
-                    SourceLocation RPLoc) { // "({..})"
+ExprResult Sema::ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,
+                               SourceLocation RPLoc) { // "({..})"
   assert(SubStmt && isa<CompoundStmt>(SubStmt) && "Invalid action invocation!");
   CompoundStmt *Compound = cast<CompoundStmt>(SubStmt);
 
@@ -13939,9 +13938,18 @@ Sema::ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
     }
   }
 
+  bool IsDependentContext = false;
+  if (S)
+    IsDependentContext = S->getTemplateParamParent() != nullptr;
+  else
+    // FIXME: This is not correct when substituting inside a templated
+    // context that isn't a DeclContext (such as a variable template).
+    IsDependentContext = CurContext->isDependentContext();
+
   // FIXME: Check that expression type is complete/non-abstract; statement
   // expressions are not lvalues.
-  Expr *ResStmtExpr = new (Context) StmtExpr(Compound, Ty, LPLoc, RPLoc);
+  Expr *ResStmtExpr =
+      new (Context) StmtExpr(Compound, Ty, LPLoc, RPLoc, IsDependentContext);
   if (StmtExprMayBindToTemp)
     return MaybeBindToTemporary(ResStmtExpr);
   return ResStmtExpr;