Oleksandr T.
bb6d2bea64
Fixes #163498 --- This PR addresses the issue of confusing diagnostics for lambdas with init-captures appearing inside braced initializers. Cases such as: ```cpp S s{[a(42), &] {}}; ``` were misparsed as C99 array designators, producing unrelated diagnostics, such as `use of undeclared identifier 'a'`, and `expected ']'` --- https://github.com/llvm/llvm-project/blob/bb9bd5f263226840194b28457ddf9861986db51f/clang/lib/Parse/ParseInit.cpp#L470 https://github.com/llvm/llvm-project/blob/bb9bd5f263226840194b28457ddf9861986db51f/clang/lib/Parse/ParseInit.cpp#L74 https://github.com/llvm/llvm-project/blob/bb9bd5f263226840194b28457ddf9861986db51f/clang/include/clang/Parse/Parser.h#L4652-L4655 https://github.com/llvm/llvm-project/blob/24c22b7de620669aed9da28de323309c44a58244/clang/lib/Parse/ParseExprCXX.cpp#L871-L879 The tentative parser now returns `Incomplete` for partially valid lambda introducers, preserving the `lambda` interpretation and allowing the proper diagnostic to be issued later. --- Clang now correctly recognizes such constructs as malformed lambda introducers and emits the expected diagnostic — for example, “capture-default must be first” — consistent with direct initialization cases such as: ```cpp S s([a(42), &] {}); ```
48 lines
2.1 KiB
C++
48 lines
2.1 KiB
C++
// RUN: %clang_cc1 -std=c++20 -Wno-unused-value -fsyntax-only -verify %s
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namespace misplaced_capture_default {
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void Test() {
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int i = 0;
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[&, i, &] {}; // expected-error {{expected variable name or 'this' in lambda capture list}}
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[&, i, = ] {}; // expected-error {{expected variable name or 'this' in lambda capture list}}
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[=, &i, &] {}; // expected-error {{expected variable name or 'this' in lambda capture list}}
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[=, &i, = ] {}; // expected-error {{expected variable name or 'this' in lambda capture list}}
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[i, &] {}; // expected-error {{capture default must be first}}
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[i, = ] {}; // expected-error {{capture default must be first}}
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[i, = x] {}; // expected-error {{expected variable name or 'this' in lambda capture list}}
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[=, &i] {}; // ok
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[&, &i] {}; // expected-error {{'&' cannot precede a capture when the capture default is '&'}}
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[&x = i] {}; // ok
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[=, &x = i] {}; // ok
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[x = &i] {}; // ok
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[=, &x = &i] {}; // expected-error {{non-const lvalue reference to type 'int *' cannot bind to a temporary of type 'int *'}}
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[&, this] {}; // expected-error {{'this' cannot be captured in this context}}
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[i, &, x = 2] {}; // expected-error {{capture default must be first}}
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[i, =, x = 2] {}; // expected-error {{capture default must be first}}
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}
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} // namespace misplaced_capture_default
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namespace misplaced_capture_default_pack {
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template <typename... Args> void Test(Args... args) {
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[&, args...] {}; // ok
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[args..., &] {}; // expected-error {{capture default must be first}}
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[=, &args...] {}; // ok
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[&, ... xs = &args] {}; // ok
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[&, ... xs = &] {}; // expected-error {{expected expression}}
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[... xs = &] {}; // expected-error {{expected expression}}
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[... xs = &args, = ] {}; // expected-error {{capture default must be first}}
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[... xs = &args, &] {}; // expected-error {{capture default must be first}}
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}
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} // namespace misplaced_capture_default_pack
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namespace GH163498 {
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struct S {
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template <class T> S(T) {}
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};
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void t() {
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S s{[a(42), &] {}}; // expected-error {{capture default must be first}}
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}
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}
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