ChuanqiXu created this revision.
ChuanqiXu added reviewers: rsmith, urnathan, aaron.ballman, erichkeane.
ChuanqiXu added a project: clang.
ChuanqiXu requested review of this revision.
Herald added a subscriber: cfe-commits.
See https://github.com/cplusplus/draft/pull/5204 for a detailed background.
Simply, the test attached to this patch should be accepted instead of being
complained about the redefinition.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D118034
Files:
clang/lib/Sema/SemaTemplate.cpp
clang/test/Modules/Inputs/redundant-template-default-arg/foo.cppm
clang/test/Modules/Inputs/redundant-template-default-arg/foo.h
clang/test/Modules/redundant-template-default-arg.cpp
Index: clang/test/Modules/redundant-template-default-arg.cpp
===================================================================
--- /dev/null
+++ clang/test/Modules/redundant-template-default-arg.cpp
@@ -0,0 +1,7 @@
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: %clang_cc1 -std=c++20
%S/Inputs/redundant-template-default-arg/foo.cppm
-I%S/Inputs/redundant-template-default-arg/. -emit-module-interface -o
%t/foo.pcm
+// RUN: %clang_cc1 -fprebuilt-module-path=%t -std=c++20 %s
-I%S/Inputs/redundant-template-default-arg/. -fsyntax-only -verify
+// expected-no-diagnostics
+import foo;
+#include "foo.h"
Index: clang/test/Modules/Inputs/redundant-template-default-arg/foo.h
===================================================================
--- /dev/null
+++ clang/test/Modules/Inputs/redundant-template-default-arg/foo.h
@@ -0,0 +1,11 @@
+template <typename T = int>
+T v;
+
+template <int T = 8>
+int v2;
+
+template <typename T>
+class my_array {};
+
+template <template <typename> typename C = my_array>
+int v3;
Index: clang/test/Modules/Inputs/redundant-template-default-arg/foo.cppm
===================================================================
--- /dev/null
+++ clang/test/Modules/Inputs/redundant-template-default-arg/foo.cppm
@@ -0,0 +1,3 @@
+module;
+#include "foo.h"
+export module foo;
Index: clang/lib/Sema/SemaTemplate.cpp
===================================================================
--- clang/lib/Sema/SemaTemplate.cpp
+++ clang/lib/Sema/SemaTemplate.cpp
@@ -2678,6 +2678,23 @@
NewParam != NewParamEnd; ++NewParam) {
// Variables used to diagnose redundant default arguments
bool RedundantDefaultArg = false;
+ // Variable used to not diagnose redundant default arguments
+ // from modules.
+ //
+ // [basic.def.odr]/13:
+ // There can be more than one definition of a
+ // ...
+ // default template argument
+ // ...
+ // in a program provided that each definition appears in a different
+ // translation unit and the definitions satisfy the [same-meaning
+ // criteria of the ODR].
+ //
+ // Simply, the design of modules allows the definition of template default
+ // argument to be repeated across translation unit. Note that the ASTReader
+ // would check the ODR criteria mentioned above so we could skip it here.
+ bool IsOldParamFromModule = false;
+
SourceLocation OldDefaultLoc;
SourceLocation NewDefaultLoc;
@@ -2710,6 +2727,8 @@
OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
+ if (OldTypeParm->isFromASTFile())
+ IsOldParamFromModule = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
@@ -2755,6 +2774,8 @@
OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
+ if (OldNonTypeParm->isFromASTFile())
+ IsOldParamFromModule = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
@@ -2799,6 +2820,8 @@
OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
SawDefaultArgument = true;
+ if (OldTemplateParm->isFromASTFile())
+ IsOldParamFromModule = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
@@ -2826,7 +2849,7 @@
Invalid = true;
}
- if (RedundantDefaultArg) {
+ if (RedundantDefaultArg && !IsOldParamFromModule) {
// C++ [temp.param]p12:
// A template-parameter shall not be given default arguments
// by two different declarations in the same scope.
Index: clang/test/Modules/redundant-template-default-arg.cpp
===================================================================
--- /dev/null
+++ clang/test/Modules/redundant-template-default-arg.cpp
@@ -0,0 +1,7 @@
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: %clang_cc1 -std=c++20 %S/Inputs/redundant-template-default-arg/foo.cppm -I%S/Inputs/redundant-template-default-arg/. -emit-module-interface -o %t/foo.pcm
+// RUN: %clang_cc1 -fprebuilt-module-path=%t -std=c++20 %s -I%S/Inputs/redundant-template-default-arg/. -fsyntax-only -verify
+// expected-no-diagnostics
+import foo;
+#include "foo.h"
Index: clang/test/Modules/Inputs/redundant-template-default-arg/foo.h
===================================================================
--- /dev/null
+++ clang/test/Modules/Inputs/redundant-template-default-arg/foo.h
@@ -0,0 +1,11 @@
+template <typename T = int>
+T v;
+
+template <int T = 8>
+int v2;
+
+template <typename T>
+class my_array {};
+
+template <template <typename> typename C = my_array>
+int v3;
Index: clang/test/Modules/Inputs/redundant-template-default-arg/foo.cppm
===================================================================
--- /dev/null
+++ clang/test/Modules/Inputs/redundant-template-default-arg/foo.cppm
@@ -0,0 +1,3 @@
+module;
+#include "foo.h"
+export module foo;
Index: clang/lib/Sema/SemaTemplate.cpp
===================================================================
--- clang/lib/Sema/SemaTemplate.cpp
+++ clang/lib/Sema/SemaTemplate.cpp
@@ -2678,6 +2678,23 @@
NewParam != NewParamEnd; ++NewParam) {
// Variables used to diagnose redundant default arguments
bool RedundantDefaultArg = false;
+ // Variable used to not diagnose redundant default arguments
+ // from modules.
+ //
+ // [basic.def.odr]/13:
+ // There can be more than one definition of a
+ // ...
+ // default template argument
+ // ...
+ // in a program provided that each definition appears in a different
+ // translation unit and the definitions satisfy the [same-meaning
+ // criteria of the ODR].
+ //
+ // Simply, the design of modules allows the definition of template default
+ // argument to be repeated across translation unit. Note that the ASTReader
+ // would check the ODR criteria mentioned above so we could skip it here.
+ bool IsOldParamFromModule = false;
+
SourceLocation OldDefaultLoc;
SourceLocation NewDefaultLoc;
@@ -2710,6 +2727,8 @@
OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
+ if (OldTypeParm->isFromASTFile())
+ IsOldParamFromModule = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
@@ -2755,6 +2774,8 @@
OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
SawDefaultArgument = true;
+ if (OldNonTypeParm->isFromASTFile())
+ IsOldParamFromModule = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
@@ -2799,6 +2820,8 @@
OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
SawDefaultArgument = true;
+ if (OldTemplateParm->isFromASTFile())
+ IsOldParamFromModule = true;
RedundantDefaultArg = true;
PreviousDefaultArgLoc = NewDefaultLoc;
} else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
@@ -2826,7 +2849,7 @@
Invalid = true;
}
- if (RedundantDefaultArg) {
+ if (RedundantDefaultArg && !IsOldParamFromModule) {
// C++ [temp.param]p12:
// A template-parameter shall not be given default arguments
// by two different declarations in the same scope.
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