[clang] [Sema][CTAD] Allow user defined conversion for copy-list-initialization (PR #94752)
Gábor Spaits via cfe-commits
cfe-commits at lists.llvm.org
Sun Jun 9 05:25:09 PDT 2024
https://github.com/spaits updated https://github.com/llvm/llvm-project/pull/94752
>From 8e1f3aa676b891c9566344ad2be046898df34a3a Mon Sep 17 00:00:00 2001
From: Gabor Spaits <gaborspaits1 at gmail.com>
Date: Fri, 7 Jun 2024 14:38:08 +0200
Subject: [PATCH 1/2] [CTAD] Allow user defined conversion
---
clang/include/clang/Sema/Initialization.h | 2 +-
clang/lib/Sema/SemaInit.cpp | 6 +-
.../SemaCXX/ctad-copy-init-list-narrowing.cpp | 90 +++++++++++++++++++
3 files changed, 93 insertions(+), 5 deletions(-)
create mode 100644 clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp
diff --git a/clang/include/clang/Sema/Initialization.h b/clang/include/clang/Sema/Initialization.h
index f443e327eaf32..4b876db436b48 100644
--- a/clang/include/clang/Sema/Initialization.h
+++ b/clang/include/clang/Sema/Initialization.h
@@ -603,7 +603,7 @@ class InitializationKind {
/// Normal context
IC_Normal,
- /// Normal context, but allows explicit conversion functionss
+ /// Normal context, but allows explicit conversion functions
IC_ExplicitConvs,
/// Implicit context (value initialization)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index ed8b226a6b39f..211b6887befa3 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -10892,8 +10892,6 @@ QualType Sema::DeduceTemplateSpecializationFromInitializer(
// FIXME: The "second phase of [over.match.list] case can also
// theoretically happen here, but it's not clear whether we can
// ever have a parameter of the right type.
- bool SuppressUserConversions = Kind.isCopyInit();
-
if (TD) {
SmallVector<Expr *, 8> TmpInits;
for (Expr *E : Inits)
@@ -10903,12 +10901,12 @@ QualType Sema::DeduceTemplateSpecializationFromInitializer(
TmpInits.push_back(E);
AddTemplateOverloadCandidate(
TD, FoundDecl, /*ExplicitArgs=*/nullptr, TmpInits, Candidates,
- SuppressUserConversions,
+ /*SuppressUserConversions=*/false,
/*PartialOverloading=*/false, AllowExplicit, ADLCallKind::NotADL,
/*PO=*/{}, AllowAggregateDeductionCandidate);
} else {
AddOverloadCandidate(GD, FoundDecl, Inits, Candidates,
- SuppressUserConversions,
+ /*SuppressUserConversions=*/false,
/*PartialOverloading=*/false, AllowExplicit);
}
};
diff --git a/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp b/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp
new file mode 100644
index 0000000000000..21b1137158d5a
--- /dev/null
+++ b/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp
@@ -0,0 +1,90 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-unused-value -std=c++20 %s
+namespace std
+{
+ typedef long unsigned int size_t;
+}
+
+namespace std
+{
+ template<class _E>
+ class initializer_list
+ {
+ public:
+ typedef _E value_type;
+ typedef const _E& reference;
+ typedef const _E& const_reference;
+ typedef size_t size_type;
+ typedef const _E* iterator;
+ typedef const _E* const_iterator;
+
+ private:
+ iterator _M_array;
+ size_type _M_len;
+
+
+ constexpr initializer_list(const_iterator __a, size_type __l)
+ : _M_array(__a), _M_len(__l) { }
+
+ public:
+ constexpr initializer_list() noexcept
+ : _M_array(0), _M_len(0) { }
+
+
+ constexpr size_type
+ size() const noexcept { return _M_len; }
+
+
+ constexpr const_iterator
+ begin() const noexcept { return _M_array; }
+
+
+ constexpr const_iterator
+ end() const noexcept { return begin() + size(); }
+ };
+
+ template<class _Tp>
+ constexpr const _Tp*
+ begin(initializer_list<_Tp> __ils) noexcept
+ { return __ils.begin(); }
+
+ template<class _Tp>
+ constexpr const _Tp*
+ end(initializer_list<_Tp> __ils) noexcept
+ { return __ils.end(); }
+}
+
+template<class T, class Y>
+class pair{
+ private:
+ T fst;
+ Y snd;
+ public:
+ pair(T f, Y s) : fst(f), snd(s) {}
+};
+
+template<class T, class Y>
+class map {
+ public:
+ map(std::initializer_list<pair<T, Y>>, int a = 4, int b = 5) {}
+};
+
+template<class T, class Y>
+class Contained {
+ public:
+ Contained(T, Y) {}
+};
+
+template<class T, class Y>
+class A {
+ public:
+ A(std::initializer_list<Contained<T, Y> >, int) {}
+};
+
+int main() {
+ map mOk ={pair{5, 'a'}, {6, 'b'}, {7, 'c'}};
+ map mNarrow ={pair{5, 'a'}, {6.0f, 'b'}, {7, 'c'}}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
+
+ A aOk = {{Contained{5, 'c'}, {5, 'c'}}, 5};
+ A aNarrowNested = {{Contained{5, 'c'}, {5.0f, 'c'}}, 5}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
+ A aNarrow = {{Contained{5, 'c'}, {5, 'c'}}, 5.0f}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
+}
>From 8e33ac051a04e5d5c6d73efdd4cf47868d5dc644 Mon Sep 17 00:00:00 2001
From: Gabor Spaits <gaborspaits1 at gmail.com>
Date: Sun, 9 Jun 2024 14:22:42 +0200
Subject: [PATCH 2/2] Simplify boiler plate and re-organize tests
---
.../SemaCXX/ctad-copy-init-list-narrowing.cpp | 95 +++++++------------
1 file changed, 35 insertions(+), 60 deletions(-)
diff --git a/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp b/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp
index 21b1137158d5a..a2de4cf8a2f90 100644
--- a/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp
+++ b/clang/test/SemaCXX/ctad-copy-init-list-narrowing.cpp
@@ -1,65 +1,25 @@
// RUN: %clang_cc1 -fsyntax-only -verify -Wno-unused-value -std=c++20 %s
-namespace std
-{
- typedef long unsigned int size_t;
-}
-
-namespace std
-{
- template<class _E>
- class initializer_list
- {
- public:
- typedef _E value_type;
- typedef const _E& reference;
- typedef const _E& const_reference;
- typedef size_t size_type;
- typedef const _E* iterator;
- typedef const _E* const_iterator;
-
- private:
- iterator _M_array;
- size_type _M_len;
-
-
- constexpr initializer_list(const_iterator __a, size_type __l)
- : _M_array(__a), _M_len(__l) { }
-
- public:
- constexpr initializer_list() noexcept
- : _M_array(0), _M_len(0) { }
-
-
- constexpr size_type
- size() const noexcept { return _M_len; }
-
- constexpr const_iterator
- begin() const noexcept { return _M_array; }
+namespace std {
+ typedef decltype(sizeof(int)) size_t;
+ template <typename E>
+ struct initializer_list
+ {
+ const E *p;
+ size_t n;
+ initializer_list(const E *p, size_t n) : p(p), n(n) {}
+ };
- constexpr const_iterator
- end() const noexcept { return begin() + size(); }
- };
-
- template<class _Tp>
- constexpr const _Tp*
- begin(initializer_list<_Tp> __ils) noexcept
- { return __ils.begin(); }
-
- template<class _Tp>
- constexpr const _Tp*
- end(initializer_list<_Tp> __ils) noexcept
- { return __ils.end(); }
-}
+ struct string {
+ string(const char *);
+ };
+ // Classes to use to reproduce the exact scenario present in 62925.
template<class T, class Y>
class pair{
- private:
- T fst;
- Y snd;
public:
- pair(T f, Y s) : fst(f), snd(s) {}
+ pair(T f, Y s) {}
};
template<class T, class Y>
@@ -68,6 +28,10 @@ class map {
map(std::initializer_list<pair<T, Y>>, int a = 4, int b = 5) {}
};
+} // namespace std
+
+
+// Classes to test different levels of nestings and conversions.
template<class T, class Y>
class Contained {
public:
@@ -80,11 +44,22 @@ class A {
A(std::initializer_list<Contained<T, Y> >, int) {}
};
-int main() {
- map mOk ={pair{5, 'a'}, {6, 'b'}, {7, 'c'}};
- map mNarrow ={pair{5, 'a'}, {6.0f, 'b'}, {7, 'c'}}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
- A aOk = {{Contained{5, 'c'}, {5, 'c'}}, 5};
- A aNarrowNested = {{Contained{5, 'c'}, {5.0f, 'c'}}, 5}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
- A aNarrow = {{Contained{5, 'c'}, {5, 'c'}}, 5.0f}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
+// This is the almost the exact code that was in issue #62925.
+void testOneLevelNesting() {
+ std::map mOk = {std::pair{5, 'a'}, {6, 'b'}, {7, 'c'}};
+
+ // Verify that narrowing conversion is disabled in the first level of nesting.
+ std::map mNarrow = {std::pair{5, 'a'}, {6.0f, 'b'}, {7, 'c'}}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
+}
+
+void testMultipleLevelNesting() {
+ A aOk = {{Contained{5, 'c'}, {5, 'c'}}, 5};
+
+ // Verify that narrowing conversion is disabled when it is not in a nested
+ // in another std::initializer_list, but it happens in the most outer one.
+ A aNarrowNested = {{Contained{5, 'c'}, {5.0f, 'c'}}, 5}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
+
+ // Verify that narrowing conversion is disabled in the first level of nesting.
+ A aNarrow = {{Contained{5, 'c'}, {5, 'c'}}, 5.0f}; // expected-error {{type 'float' cannot be narrowed to 'int' in initializer list}} // expected-note {{insert an explicit cast to silence this issue}}
}
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