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)
diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index 16956c2..bcb9605 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -3955,14 +3955,14 @@
Stmt *SubStmt;
SourceLocation LParenLoc, RParenLoc;
public:
- // FIXME: Does type-dependence need to be computed differently?
- // FIXME: Do we need to compute instantiation instantiation-dependence for
- // statements? (ugh!)
StmtExpr(CompoundStmt *substmt, QualType T,
- SourceLocation lp, SourceLocation rp) :
+ SourceLocation lp, SourceLocation rp, bool InDependentContext) :
+ // Note: we treat a statement-expression in a dependent context as always
+ // being value- and instantiation-dependent. This matches the behavior of
+ // lambda-expressions and GCC.
Expr(StmtExprClass, T, VK_RValue, OK_Ordinary,
- T->isDependentType(), false, false, false),
- SubStmt(substmt), LParenLoc(lp), RParenLoc(rp) { }
+ T->isDependentType(), InDependentContext, InDependentContext, false),
+ SubStmt(substmt), LParenLoc(lp), RParenLoc(rp) {}
/// Build an empty statement expression.
explicit StmtExpr(EmptyShell Empty) : Expr(StmtExprClass, Empty) { }
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 697d191..2b5f7c1 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -4923,7 +4923,7 @@
LabelDecl *TheDecl);
void ActOnStartStmtExpr();
- ExprResult ActOnStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
+ ExprResult ActOnStmtExpr(Scope *S, SourceLocation LPLoc, Stmt *SubStmt,
SourceLocation RPLoc); // "({..})"
// Handle the final expression in a statement expression.
ExprResult ActOnStmtExprResult(ExprResult E);
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 1f2ce30..f423615 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -6724,8 +6724,9 @@
SourceLocation ToLParenLoc, ToRParenLoc;
std::tie(ToSubStmt, ToType, ToLParenLoc, ToRParenLoc) = *Imp;
- return new (Importer.getToContext()) StmtExpr(
- ToSubStmt, ToType, ToLParenLoc, ToRParenLoc);
+ return new (Importer.getToContext())
+ StmtExpr(ToSubStmt, ToType, ToLParenLoc, ToRParenLoc,
+ E->isInstantiationDependent());
}
ExpectedStmt ASTNodeImporter::VisitUnaryOperator(UnaryOperator *E) {
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 1eb3ad6..ad9627a 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -2655,7 +2655,8 @@
// If the substmt parsed correctly, build the AST node.
if (!Stmt.isInvalid()) {
- Result = Actions.ActOnStmtExpr(OpenLoc, Stmt.get(), Tok.getLocation());
+ Result = Actions.ActOnStmtExpr(getCurScope(), OpenLoc, Stmt.get(),
+ Tok.getLocation());
} else {
Actions.ActOnStmtExprError();
}
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 2956261..63d8d75 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -13908,9 +13908,8 @@
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 @@
}
}
+ 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;
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 98af7fb..705abdb 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -6800,8 +6800,9 @@
// a new AsmStmtWithTemporaries.
CompoundStmt *CompStmt = CompoundStmt::Create(
Context, SubStmt, SourceLocation(), SourceLocation());
- Expr *E = new (Context) StmtExpr(CompStmt, Context.VoidTy, SourceLocation(),
- SourceLocation());
+ Expr *E = new (Context)
+ StmtExpr(CompStmt, Context.VoidTy, SourceLocation(), SourceLocation(),
+ CurContext->isDependentContext());
return MaybeCreateExprWithCleanups(E);
}
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index d610535..0892f96 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -2526,10 +2526,9 @@
///
/// By default, performs semantic analysis to build the new expression.
/// Subclasses may override this routine to provide different behavior.
- ExprResult RebuildStmtExpr(SourceLocation LParenLoc,
- Stmt *SubStmt,
- SourceLocation RParenLoc) {
- return getSema().ActOnStmtExpr(LParenLoc, SubStmt, RParenLoc);
+ ExprResult RebuildStmtExpr(SourceLocation LParenLoc, Stmt *SubStmt,
+ SourceLocation RParenLoc) {
+ return getSema().ActOnStmtExpr(nullptr, LParenLoc, SubStmt, RParenLoc);
}
/// Build a new __builtin_choose_expr expression.
@@ -11801,6 +11800,8 @@
NewTrailingRequiresClause = getDerived().TransformExpr(TRC);
// Create the local class that will describe the lambda.
+ // FIXME: KnownDependent below is wrong when substituting inside a templated
+ // context that isn't a DeclContext (such as a variable template).
CXXRecordDecl *OldClass = E->getLambdaClass();
CXXRecordDecl *Class
= getSema().createLambdaClosureType(E->getIntroducerRange(),
diff --git a/clang/test/SemaTemplate/dependent-expr.cpp b/clang/test/SemaTemplate/dependent-expr.cpp
index bb1e239..e333ed9 100644
--- a/clang/test/SemaTemplate/dependent-expr.cpp
+++ b/clang/test/SemaTemplate/dependent-expr.cpp
@@ -1,5 +1,4 @@
// RUN: %clang_cc1 -fsyntax-only -verify %s
-// expected-no-diagnostics
// PR5908
template <typename Iterator>
@@ -108,3 +107,22 @@
};
template struct A<0>;
}
+
+template<typename T> void stmt_expr_1() {
+ static_assert( ({ false; }), "" );
+}
+void stmt_expr_2() {
+ static_assert( ({ false; }), "" ); // expected-error {{failed}}
+}
+
+namespace PR45083 {
+ struct A { bool x; };
+
+ template<typename> struct B : A {
+ void f() {
+ const int n = ({ if (x) {} 0; });
+ }
+ };
+
+ template void B<int>::f();
+}
