Commit 4d33a8df authored by Saar Raz's avatar Saar Raz
Browse files

[Concepts] Add ExpressionEvaluationContexts to instantiation of constraints 

Proper ExpressionEvaluationContext were not being entered when instantiating constraint
expressions, which caused assertion failures in certain cases, including bug #44614.
parent 9c2eb220

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

+8 −0
Original line number Diff line number Diff line
@@ -1848,6 +1848,8 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl( 
  // FIXME: Concepts: Do not substitute into constraint expressions

  Expr *TrailingRequiresClause = D->getTrailingRequiresClause();

  if (TrailingRequiresClause) {

    EnterExpressionEvaluationContext ConstantEvaluated(

        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

    ExprResult SubstRC = SemaRef.SubstExpr(TrailingRequiresClause,

                                           TemplateArgs);

    if (SubstRC.isInvalid())
@@ -2186,6 +2188,8 @@ Decl *TemplateDeclInstantiator::VisitCXXMethodDecl( 
  // FIXME: Concepts: Do not substitute into constraint expressions

  Expr *TrailingRequiresClause = D->getTrailingRequiresClause();

  if (TrailingRequiresClause) {

    EnterExpressionEvaluationContext ConstantEvaluated(

        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

    ExprResult SubstRC = SemaRef.SubstExpr(TrailingRequiresClause,

                                           TemplateArgs);

    if (SubstRC.isInvalid())
@@ -2525,6 +2529,8 @@ Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl( 
    TemplateArgumentListInfo InstArgs;



    if (TemplArgInfo) {

      EnterExpressionEvaluationContext ConstantEvaluated(

        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

      InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);

      InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);

      if (SemaRef.Subst(TemplArgInfo->getTemplateArgs(),
@@ -3729,6 +3735,8 @@ TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) { 
  // checking satisfaction.

  Expr *InstRequiresClause = nullptr;

  if (Expr *E = L->getRequiresClause()) {

    EnterExpressionEvaluationContext ConstantEvaluated(

        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);

    ExprResult Res = SemaRef.SubstExpr(E, TemplateArgs);

    if (Res.isInvalid() || !Res.isUsable()) {

      return nullptr;

clang/test/SemaTemplate/instantiate-requires-clause.cpp

+12 −0
Original line number Diff line number Diff line
@@ -39,3 +39,15 @@ struct S { 
};



static_assert(S<void>::f(1));



constexpr auto value = 0;



template<typename T>

struct S2 {

  template<typename = void> requires(value, true)

  static constexpr auto f() requires(value, true) {

  }

};



static_assert((S2<int>::f(), true));