[Clang] [C++26] Expansion Statements (Part 11: Final Touches and Tests)

[Sirraide]

This makes some very minor final changes that didn’t really fit anywhere else, and in addition it also adds the AST dump tests because I wasn’t quite sure where else to put them (we can’t put them with the other AST stuff since this requires Sema).

[Sirraide]

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• [Clang] [C++26] Expansion Statements (Part 11: Final Touches and Tests) #169690 👈 (View in Graphite)
• [Clang] [C++26] Expansion Statements (Part 10: Expansion Limit) #169689
• [Clang] [C++26] Expansion Statements (Part 9: Control Flow) #169688
• [Clang] [C++26] Expansion Statements (Part 8: Codegen) #169687
• [Clang] [C++26] Expansion Statements (Part 7: Constexpr support and tests) #169686
• [Clang] [C++26] Expansion Statements (Part 6: Destructuring Expansion Statements) #169685
• [Clang] [C++26] Expansion Statements (Part 5: Iterating Expansion Statements) #169684
• [Clang] [NFC] Expansion Statements (Part 4: for-range refactor) #169683
• [Clang] [C++26] Expansion Statements (Part 3: Enumerating Expansion Statements) #169682
• [Clang] [C++26] Expansion Statements (Part 2: Parsing and Parser Tests) #169681
• [Clang] [C++26] Expansion Statements (Part 1: AST) #169680
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[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-codegen

Author: None (Sirraide)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/169690.diff

5 Files Affected:

• (modified) clang/docs/ReleaseNotes.rst (+2)
• (modified) clang/include/clang/Basic/DiagnosticCommonKinds.td (-4)
• (added) clang/test/AST/ast-dump-expansion-stmt.cpp (+49)
• (added) clang/test/AST/ast-print-expansion-stmts.cpp (+104)
• (modified) clang/www/cxx_status.html (+1-1)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 51f07256c5d9f..14f31c0ee5a2b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -187,6 +187,8 @@ C++2c Feature Support
   At this timem, references to constexpr and decomposition of *tuple-like* types are not supported
   (only arrays and aggregates are).
 
+- Implemented `P1306R5 <https://wg21.link/P1306R5>`_ Expansion Statements.
+
 C++23 Feature Support
 ^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
index 0b9225980e826..6e50e225a8cc1 100644
--- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -22,10 +22,6 @@ def select_constexpr_spec_kind : TextSubstitution<
 def fatal_too_many_errors
   : Error<"too many errors emitted, stopping now">, DefaultFatal;
 
-// TODO: Remove this.
-def err_expansion_statements_todo : Error<
-  "TODO (expansion statements)">;
-
 def warn_stack_exhausted : Warning<
   "stack nearly exhausted; compilation time may suffer, and "
   "crashes due to stack overflow are likely">,
diff --git a/clang/test/AST/ast-dump-expansion-stmt.cpp b/clang/test/AST/ast-dump-expansion-stmt.cpp
new file mode 100644
index 0000000000000..146157e2c13e6
--- /dev/null
+++ b/clang/test/AST/ast-dump-expansion-stmt.cpp
@@ -0,0 +1,49 @@
+// Test without serialization:
+// RUN: %clang_cc1 -std=c++26 -triple x86_64-unknown-unknown -ast-dump %s
+//
+// Test with serialization:
+// RUN: %clang_cc1 -std=c++26 -triple x86_64-unknown-unknown -emit-pch -o %t %s
+// RUN: %clang_cc1 -x c++ -std=c++26 -triple x86_64-unknown-unknown -include-pch %t -ast-dump-all /dev/null \
+// RUN: | sed -e "s/ <undeserialized declarations>//" -e "s/ imported//"
+
+template <typename T, __SIZE_TYPE__ size>
+struct Array {
+  T data[size]{};
+  constexpr const T* begin() const { return data; }
+  constexpr const T* end() const { return data + size; }
+};
+
+void foo(int);
+
+template <typename T>
+void test(T t) {
+  // CHECK:      CXXExpansionStmtDecl
+  // CHECK-NEXT:   CXXEnumeratingExpansionStmtPattern
+  // CHECK:        CXXExpansionStmtInstantiation
+  template for (auto x : {1, 2, 3}) {
+    foo(x);
+  }
+
+  // CHECK:      CXXExpansionStmtDecl
+  // CHECK-NEXT:   CXXIteratingExpansionStmtPattern
+  // CHECK:        CXXExpansionStmtInstantiation
+  static constexpr Array<int, 3> a;
+  template for (auto x : a) {
+    foo(x);
+  }
+
+  // CHECK:      CXXExpansionStmtDecl
+  // CHECK-NEXT:   CXXDestructuringExpansionStmtPattern
+  // CHECK:        CXXExpansionStmtInstantiation
+  int arr[3]{1, 2, 3};
+  template for (auto x : arr) {
+    foo(x);
+  }
+
+  // CHECK:      CXXExpansionStmtDecl
+  // CHECK-NEXT:   CXXDependentExpansionStmtPattern
+  // CHECK-NOT:    CXXExpansionStmtInstantiation
+  template for (auto x : t) {
+    foo(x);
+  }
+}
diff --git a/clang/test/AST/ast-print-expansion-stmts.cpp b/clang/test/AST/ast-print-expansion-stmts.cpp
new file mode 100644
index 0000000000000..bb9f79c6644c0
--- /dev/null
+++ b/clang/test/AST/ast-print-expansion-stmts.cpp
@@ -0,0 +1,104 @@
+// Without serialization:
+// RUN: %clang_cc1 -std=c++26 -ast-print %s | FileCheck %s
+//
+// With serialization:
+// RUN: %clang_cc1 -std=c++26 -emit-pch -o %t %s
+// RUN: %clang_cc1 -x c++ -std=c++26 -include-pch %t -ast-print  /dev/null | FileCheck %s
+
+template <typename T, __SIZE_TYPE__ size>
+struct Array {
+  T data[size]{};
+  constexpr const T* begin() const { return data; }
+  constexpr const T* end() const { return data + size; }
+};
+
+// CHECK: void foo(int);
+void foo(int);
+
+// CHECK: template <typename T> void test(T t) {
+template <typename T>
+void test(T t) {
+  // Enumerating expansion statement.
+  //
+  // CHECK:      template for (auto x : { 1, 2, 3 }) {
+  // CHECK-NEXT:     foo(x);
+  // CHECK-NEXT: }
+  template for (auto x : {1, 2, 3}) {
+    foo(x);
+  }
+
+  // Iterating expansion statement.
+  //
+  // CHECK:      static constexpr Array<int, 3> a;
+  // CHECK-NEXT: template for (auto x : a) {
+  // CHECK-NEXT:   foo(x);
+  // CHECK-NEXT: }
+  static constexpr Array<int, 3> a;
+  template for (auto x : a) {
+    foo(x);
+  }
+
+  // Destructuring expansion statement.
+  //
+  // CHECK:      int arr[3]{1, 2, 3};
+  // CHECK-NEXT: template for (auto x : arr) {
+  // CHECK-NEXT:   foo(x);
+  // CHECK-NEXT: }
+  int arr[3]{1, 2, 3};
+  template for (auto x : arr) {
+    foo(x);
+  }
+
+  // Dependent expansion statement.
+  //
+  // CHECK:      template for (auto x : t) {
+  // CHECK-NEXT:   foo(x);
+  // CHECK-NEXT: }
+  template for (auto x : t) {
+    foo(x);
+  }
+}
+
+// CHECK: template <typename T> void test2(T t) {
+template <typename T>
+void test2(T t) {
+  // Enumerating expansion statement.
+  //
+  // CHECK:      template for (int x : { 1, 2, 3 }) {
+  // CHECK-NEXT:     foo(x);
+  // CHECK-NEXT: }
+  template for (int x : {1, 2, 3}) {
+    foo(x);
+  }
+
+  // Iterating expansion statement.
+  //
+  // CHECK:      static constexpr Array<int, 3> a;
+  // CHECK-NEXT: template for (int x : a) {
+  // CHECK-NEXT:   foo(x);
+  // CHECK-NEXT: }
+  static constexpr Array<int, 3> a;
+  template for (int x : a) {
+    foo(x);
+  }
+
+  // Destructuring expansion statement.
+  //
+  // CHECK:      int arr[3]{1, 2, 3};
+  // CHECK-NEXT: template for (int x : arr) {
+  // CHECK-NEXT:   foo(x);
+  // CHECK-NEXT: }
+  int arr[3]{1, 2, 3};
+  template for (int x : arr) {
+    foo(x);
+  }
+
+  // Dependent expansion statement.
+  //
+  // CHECK:      template for (int x : t) {
+  // CHECK-NEXT:   foo(x);
+  // CHECK-NEXT: }
+  template for (int x : t) {
+    foo(x);
+  }
+}
diff --git a/clang/www/cxx_status.html b/clang/www/cxx_status.html
index 2618ff930a0e4..0bb2d5440775a 100755
--- a/clang/www/cxx_status.html
+++ b/clang/www/cxx_status.html
@@ -317,7 +317,7 @@ <h2 id="cxx26">C++2c implementation status</h2>
  <tr>
   <td>Expansion Statements</td>
   <td><a href="https://wg21.link/P1306">P1306R5</a></td>
-  <td class="none" align="center">No</td>
+  <td class="unreleased" align="center">Clang 22</td>
   </tr>
   <tr>
    <td>constexpr virtual inheritance</td>