[PATCH] D113838: Sema: Don't erroneously reject `void{}`
Aaron Puchert via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Sat Nov 13 18:19:20 PST 2021
aaronpuchert created this revision.
aaronpuchert added a reviewer: rsmith.
aaronpuchert requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
This is explicitly allowed via [expr.type.conv], if the initialization
list is empty.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D113838
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaInit.cpp
clang/test/CXX/expr/expr.post/expr.type.conv/p2.cpp
clang/test/SemaCXX/attr-annotate.cpp
clang/test/SemaCXX/cxx2a-explicit-bool.cpp
Index: clang/test/SemaCXX/cxx2a-explicit-bool.cpp
===================================================================
--- clang/test/SemaCXX/cxx2a-explicit-bool.cpp
+++ clang/test/SemaCXX/cxx2a-explicit-bool.cpp
@@ -73,8 +73,8 @@
template <typename T> struct E {
// expected-note at -1+ {{candidate constructor}}
- explicit((T{}, false))
- // expected-error at -1 {{illegal initializer type 'void'}}
+ explicit(((T&&)T{}, false))
+ // expected-error at -1 {{cannot form a reference to 'void'}}
E(int);
};
Index: clang/test/SemaCXX/attr-annotate.cpp
===================================================================
--- clang/test/SemaCXX/attr-annotate.cpp
+++ clang/test/SemaCXX/attr-annotate.cpp
@@ -42,8 +42,8 @@
template<typename T>
struct B {
- [[clang::annotate("test", ((void)T{}, 9))]] void t() {}
- // expected-error at -1 {{illegal initializer type 'void'}}
+ [[clang::annotate("test", ((void)T{1}, 9))]] void t() {}
+ // expected-error at -1 {{initializer list for 'void' must be empty}}
};
B<int> b;
B<void> b1;
Index: clang/test/CXX/expr/expr.post/expr.type.conv/p2.cpp
===================================================================
--- /dev/null
+++ clang/test/CXX/expr/expr.post/expr.type.conv/p2.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+
+void paren_list() {
+ return void();
+}
+
+void brace_list() {
+ return void{};
+}
+
+void brace_list_nonempty() {
+ return void{1}; // expected-error {{initializer list for 'void' must be empty}}
+}
+
+void brace_list_nested_nonempty() {
+ return void{{}}; // expected-error {{initializer list for 'void' must be empty}}
+}
Index: clang/lib/Sema/SemaInit.cpp
===================================================================
--- clang/lib/Sema/SemaInit.cpp
+++ clang/lib/Sema/SemaInit.cpp
@@ -1308,7 +1308,16 @@
CheckArrayType(Entity, IList, DeclType, Zero,
SubobjectIsDesignatorContext, Index,
StructuredList, StructuredIndex);
- } else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
+ } else if (DeclType->isVoidType()) {
+ // [expr.type.conv]p2: Otherwise, if the type is cv void and the
+ // initializer is () or {} (after pack expansion, if any), the expression
+ // is a prvalue of type void that performs no initialization.
+ if (IList->getNumInits() > 0) {
+ if (!VerifyOnly)
+ SemaRef.Diag(IList->getBeginLoc(), diag::err_init_list_void_nonempty);
+ hadError = true;
+ }
+ } else if (DeclType->isFunctionType()) {
// This type is invalid, issue a diagnostic.
++Index;
if (!VerifyOnly)
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5845,6 +5845,8 @@
def err_illegal_initializer : Error<
"illegal initializer (only variables can be initialized)">;
def err_illegal_initializer_type : Error<"illegal initializer type %0">;
+def err_init_list_void_nonempty : Error<
+ "initializer list for 'void' must be empty">;
def ext_init_list_type_narrowing : ExtWarn<
"type %0 cannot be narrowed to %1 in initializer list">,
InGroup<CXX11Narrowing>, DefaultError, SFINAEFailure;
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