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[Clang] Fix a crash when dumping a pack indexing type. #80439

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Merged
merged 3 commits into from
Feb 2, 2024
Merged

[Clang] Fix a crash when dumping a pack indexing type. #80439

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4a726e2
[Clang] Fix a crash when dumping a pack indexing type.
cor3ntin Feb 2, 2024
0bbf2c3
generalize the test
cor3ntin Feb 2, 2024
e9f4ec9
generalize the test harder
cor3ntin Feb 2, 2024
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6 changes: 3 additions & 3 deletions clang/lib/AST/TypePrinter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1195,10 +1195,10 @@ void TypePrinter::printDecltypeBefore(const DecltypeType *T, raw_ostream &OS) {

void TypePrinter::printPackIndexingBefore(const PackIndexingType *T,
raw_ostream &OS) {
if (T->isInstantiationDependentType())
OS << T->getPattern() << "...[" << T->getIndexExpr() << "]";
else
if (T->hasSelectedType())
OS << T->getSelectedType();
else
OS << T->getPattern() << "...[" << T->getIndexExpr() << "]";
spaceBeforePlaceHolder(OS);
}

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25 changes: 25 additions & 0 deletions clang/test/AST/ast-dump-pack-indexing-crash.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
// RUN: not %clang_cc1 -std=c++2c -ast-dump %s | FileCheck %s

namespace InvalidPacksShouldNotCrash {

struct NotAPack;
template <typename T, auto V, template<typename> typename Tp>
void not_pack() {
int i = 0;
i...[0]; // expected-error {{i does not refer to the name of a parameter pack}}
V...[0]; // expected-error {{V does not refer to the name of a parameter pack}}
NotAPack...[0] a; // expected-error{{'NotAPack' does not refer to the name of a parameter pack}}
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If you change this to an array, such as

NotAPack...[0] a[2];

then I think you hit the same kind of infinite recursion as we see downstream even without the array nodtation.

T...[0] b; // expected-error{{'T' does not refer to the name of a parameter pack}}
Tp...[0] c; // expected-error{{'Tp' does not refer to the name of a parameter pack}}
}

// CHECK: FunctionDecl {{.*}} not_pack 'void ()'
// CHECK: DeclStmt {{.*}}
// CHECK: DeclStmt {{.*}}
// CHECK-NEXT: VarDecl {{.*}} a 'NotAPack...{{.*}}'
// CHECK-NEXT: DeclStmt {{.*}}
// CHECK-NEXT: VarDecl {{.*}} 'T...{{.*}}'
// CHECK-NEXT: DeclStmt {{.*}}
// CHECK-NEXT: VarDecl {{.*}} c 'Tp...{{.*}}'

}