Crash inside TemplateInstantiator on complex constraint expressions

[alexander-shaposhnikov]

template <class T1, class T2>
int foo(const T1 &t1, const T2 &t2)
  requires requires {
    { t1 < t2 };
    { t2 < t1 };
  }
{
  return 1;
}

template <class T3, class T4>
int foo(const T3 &t3, const T4 &t4)
  requires requires {
    { t3 + t4 };
  }
{
  return 2;
}

To reproduce the issue one has to reapply the changes from
60bee9f

#12 0x00005560e45a2958 clang::LocalInstantiationScope::findInstantiationOf(clang::Decl const*) 
llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:4104:3
#13 0x00005560e4616113 clang::Sema::FindInstantiatedDecl(clang::SourceLocation, clang::NamedDecl*, clang::MultiLevelTemplateArgumentList const&, bool) 
llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:6081:16
#14 0x00005560e45a4f2e (anonymous namespace)::TemplateInstantiator::TransformDecl(clang::SourceLocation, clang::Decl*) 
llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:1526:3
#15 0x00005560e45be4ae clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclRefExpr(clang::DeclRefExpr*)
llvm-project/clang/lib/Sema/TreeTransform.h:10761:44
#16 0x00005560e45ad1d2 (anonymous namespace)::TemplateInstantiator::TransformDeclRefExpr(clang::DeclRefExpr*) llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2035:21
#17 0x00005560e459ef71 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) 
llvm-project/build/tools/clang/include/clang/AST/StmtNodes.inc:1109:1
#18 0x00005560e45a5e79 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformBinaryOperator(clang::BinaryOperator*) 
llvm-project/clang/lib/Sema/TreeTransform.h:11400:33
#19 0x00005560e459e647 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) 
llvm-project/build/tools/clang/include/clang/AST/StmtNodes.inc:783:1
#20 0x00005560e45c6797 (anonymous namespace)::TemplateInstantiator::TransformExprRequirement(clang::concepts::ExprRequirement*)
llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2316:31
#21 0x00005560e45c4d14 (anonymous namespace)::TemplateInstantiator::TransformRequiresExprRequirements(llvm::ArrayRef<clang::concepts::Requirement*>, llvm::SmallVectorImpl<clang::concepts::Requirement*>&) 
llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:1421:22
#22 0x00005560e45c46db clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformRequiresExpr(clang::RequiresExpr*) 
llvm-project/clang/lib/Sema/TreeTransform.h:12837:7
#23 0x00005560e45b3832 (anonymous namespace)::TemplateInstantiator::TransformRequiresExpr(clang::RequiresExpr*) 
llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:1393:40
#24 0x00005560e459f996 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformExpr(clang::Expr*) 
llvm-project/build/tools/clang/include/clang/AST/StmtNodes.inc:1443:1
#25 0x00005560e459fcd1 clang::Sema::SubstConstraintExpr(clang::Expr*, clang::MultiLevelTemplateArgumentList const&) 
llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:3979:23
#26 0x00005560e34d54eb SubstituteConstraintExpression(clang::Sema&, clang::NamedDecl const*, clang::Expr const*, clang::NamedDecl const*) 
llvm-project/clang/lib/Sema/SemaConcept.cpp:785:9
#27 0x00005560e34d52ad clang::Sema::AreConstraintExpressionsEqual(clang::NamedDecl const*, clang::Expr const*, clang::NamedDecl const*, clang::Expr const*) 
llvm-project/clang/lib/Sema/SemaConcept.cpp:798:21
#28 0x00005560e4179074 clang::Sema::IsOverload(clang::FunctionDecl*, clang::FunctionDecl*, bool, bool, bool) 
llvm-project/clang/lib/Sema/SemaOverload.cpp:1329:9
#29 0x00005560e41787b1 clang::Sema::CheckOverload(clang::Scope*, clang::FunctionDecl*, clang::LookupResult const&, clang::NamedDecl*&, bool) 
llvm-project/clang/lib/Sema/SemaOverload.cpp:1154:11
#30 0x00005560e35c1145 clang::Sema::CheckFunctionDeclaration(clang::Scope*, clang::FunctionDecl*, clang::LookupResult&, bool, bool) 
llvm-project/clang/lib/Sema/SemaDecl.cpp:11661:7
#31 0x00005560e35b36ee clang::Sema::ActOnFunctionDeclarator(clang::Scope*, clang::Declarator&, clang::DeclContext*, clang::TypeSourceInfo*, clang::LookupResult&, llvm::MutableArrayRef<clang::TemplateParameterList*>, bool&) 
llvm-project/clang/lib/Sema/SemaDecl.cpp:10392:28
#32 0x00005560e35ae674 clang::Sema::HandleDeclarator(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>)
llvm-project/clang/lib/Sema/SemaDecl.cpp:6422:9
#33 0x00005560e35cf51d clang::Sema::ActOnStartOfFunctionDef(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>, clang::Sema::SkipBodyInfo*, clang::Sema::FnBodyKind) 
llvm-project/clang/lib/Sema/SemaDecl.cpp:14970:14
#34 0x00005560e30e0f60 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) 
llvm-project/clang/lib/Parse/Parser.cpp:1398:9

p.s.
inside TransformRequiresExpr we seem to take care of E->getLocalParameters()
(see also https://github.com/llvm/llvm-project/blob/main/clang/lib/Sema/SemaTemplateInstantiate.cpp#L1374) ,
but if the parameters are referenced inside Requirements we get into trouble.

cc: @erichkeane

[llvmbot]

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