487967af82
Close https://github.com/llvm/llvm-project/issues/88400 For the reproducer: ``` //--- header.h namespace N { template<typename T> concept X = true; template<X T> class Y { public: template<X U> friend class Y; }; inline Y<int> x; } //--- bar.cppm module; export module bar; namespace N { // To make sure N::Y won't get elided. using N::x; } //--- foo.cc // expected-no-diagnostics import bar; void y() { N::Y<int> y{}; }; ``` it will crash. The root cause is that in `StoredDeclsList::replaceExternalDecls`, we will replace the existing declarations with external declarations. Then for the reproducer, the redecl chain for Y is like: ``` Y (Local) -> Y (Local, friend) -> Y (Imported) -> Y(Imported, friend) ``` Before the lookup, the stored lookup result is `Y(Local)` then we find `Y(Imported)`. And now we repalce `Y(Local)` with `Y(Imported)`. But `Y(Imported)` is not visible. So we tried to find if there is any redeclarations visible but we find `Y(Local, friend)`, then problem happens. The solution is try to avoid the replace to happen if the external declaration has lower visibility then we can always find the local declarations. This may help the lookup performance slightly. Also I found the implementation of `StoredDeclsList::replaceExternalDecls` is not efficiency. It has an `O(n*m)` complexities. But let's improve that in the future.
62 lines
1.1 KiB
C++
62 lines
1.1 KiB
C++
// RUN: rm -rf %t
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// RUN: mkdir -p %t
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// RUN: split-file %s %t
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//
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// RUN: %clang_cc1 -std=c++20 %t/bar.cppm -emit-module-interface -o %t/bar.pcm
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// RUN: %clang_cc1 -std=c++20 %t/foo.cc -fmodule-file=bar=%t/bar.pcm -fsyntax-only -verify
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// RUN: %clang_cc1 -std=c++20 %t/bar.cc -fmodule-file=bar=%t/bar.pcm -fsyntax-only -verify
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//
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// RUN: %clang_cc1 -std=c++20 %t/bar.cppm -emit-reduced-module-interface -o %t/bar.pcm
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// RUN: %clang_cc1 -std=c++20 %t/foo.cc -fmodule-file=bar=%t/bar.pcm -fsyntax-only -verify
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// RUN: %clang_cc1 -std=c++20 %t/bar.cc -fmodule-file=bar=%t/bar.pcm -fsyntax-only -verify
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//--- header.h
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#pragma once
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namespace N {
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template<typename T>
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concept X = true;
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template<X T>
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class Y {
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public:
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template<X U>
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friend class Y;
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};
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inline Y<int> x;
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}
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//--- bar.cppm
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module;
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#include "header.h"
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export module bar;
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namespace N {
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// To make sure N::Y won't get elided.
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using N::x;
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}
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//--- foo.cc
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// expected-no-diagnostics
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#include "header.h"
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import bar;
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void y() {
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N::Y<int> y{};
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};
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//--- bar.cc
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// expected-no-diagnostics
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import bar;
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#include "header.h"
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void y() {
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N::Y<int> y{};
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};
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