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release/20.x: [Clang] Do not emit nodiscard warnings for the base expr of static member access (#131450) #131474

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Merged
merged 3 commits into from
Mar 18, 2025
Merged

release/20.x: [Clang] Do not emit nodiscard warnings for the base expr of static member access (#131450) #131474

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e3f0ce3
[Clang] Do not emit nodiscard warnings for the base expr of static me…
cor3ntin Mar 15, 2025
2044b18
fix abi
cor3ntin Mar 17, 2025
2dc152f
fix abi (again)
cor3ntin Mar 18, 2025
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5 changes: 2 additions & 3 deletions clang/include/clang/Sema/Sema.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10671,9 +10671,8 @@ class Sema final : public SemaBase {
SourceLocation EndLoc);
void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);

/// DiagnoseDiscardedExprMarkedNodiscard - Given an expression that is
/// semantically a discarded-value expression, diagnose if any [[nodiscard]]
/// value has been discarded.

// Unused, kept in Clang 20 for ABI stability.
void DiagnoseDiscardedExprMarkedNodiscard(const Expr *E);

/// DiagnoseUnusedExprResult - If the statement passed in is an expression
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1 change: 0 additions & 1 deletion clang/lib/Sema/SemaExprMember.cpp
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Expand Up @@ -1136,7 +1136,6 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
if (Converted.isInvalid())
return true;
BaseExpr = Converted.get();
DiagnoseDiscardedExprMarkedNodiscard(BaseExpr);
return false;
};
auto ConvertBaseExprToGLValue = [&] {
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10 changes: 6 additions & 4 deletions clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp
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Expand Up @@ -164,19 +164,21 @@ struct X {

[[nodiscard]] X get_X();
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
[[nodiscard]] X* get_Ptr();
// cxx11-warning@-1 {{use of the 'nodiscard' attribute is a C++17 extension}}
void f() {
get_X(); // expected-warning{{ignoring return value of function declared with 'nodiscard' attribute}}
(void) get_X();
(void) get_X().variant_member;
(void) get_X().anonymous_struct_member;
(void) get_X().data_member;
(void) get_X().static_data_member;
// expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
(void) get_X().unscoped_enum;
// expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
(void) get_X().scoped_enum;
// expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
(void) get_X().implicit_object_member_function();
(void) get_X().static_member_function();
// expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
(void) get_Ptr()->implicit_object_member_function();
(void) get_Ptr()->static_member_function();
#if __cplusplus >= 202302L
(void) get_X().explicit_object_member_function();
#endif
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2 changes: 1 addition & 1 deletion clang/test/SemaCXX/ms-property.cpp
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Expand Up @@ -2,6 +2,7 @@
// RUN: %clang_cc1 -triple=x86_64-pc-win32 -fms-compatibility -emit-pch -o %t -verify %s
// RUN: %clang_cc1 -triple=x86_64-pc-win32 -fms-compatibility -include-pch %t %s -ast-print -o - | FileCheck %s
// RUN: %clang_cc1 -fdeclspec -fsyntax-only -verify %s -std=c++23
// expected-no-diagnostics

#ifndef HEADER
#define HEADER
Expand Down Expand Up @@ -103,7 +104,6 @@ struct X {
void f() {
(void) get_x().imp;
(void) get_x().st;
// expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
#if __cplusplus >= 202302L
(void) get_x().exp;
#endif
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