[clang] [clang-format] Disable OuterScope lambda indentation behaviour for constructor initializers (PR #66755)

[Jon Phillips via cfe-commits]

https://github.com/jp4a50 created https://github.com/llvm/llvm-project/pull/66755

By default, OuterScope aligns lambdas to the beginning of the current line. This makes sense for most types of statements within code blocks but leads to unappealing and misleading indentation for lambdas within constructor initializers.

>From e07d263a37ef37a21bb5cf424b14be83088eed3d Mon Sep 17 00:00:00 2001
From: Jon Phillips <jphillips at cloudflare.com>
Date: Tue, 19 Sep 2023 10:29:57 +0100
Subject: [PATCH] [clang-format] Disable OuterScope lambda indentation
 behaviour for constructor initializers

By default, OuterScope aligns lambdas to the beginning of the current
line. This makes sense for most types of statements within code blocks
but leads to unappealing and misleading indentation for lambdas within
constructor initializers.
---
 clang/lib/Format/ContinuationIndenter.cpp |  3 ++-
 clang/unittests/Format/FormatTest.cpp     | 30 +++++++++++++++++------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index deb3e554fdc124b..0fa70eace90f416 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -1955,7 +1955,8 @@ void ContinuationIndenter::moveStatePastScopeCloser(LineState &State) {
 
 void ContinuationIndenter::moveStateToNewBlock(LineState &State) {
   if (Style.LambdaBodyIndentation == FormatStyle::LBI_OuterScope &&
-      State.NextToken->is(TT_LambdaLBrace)) {
+      State.NextToken->is(TT_LambdaLBrace) && State.Line &&
+      !State.Line->MightBeFunctionDecl) {
     State.Stack.back().NestedBlockIndent = State.FirstIndent;
   }
   unsigned NestedBlockIndent = State.Stack.back().NestedBlockIndent;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 0d0fbdb84e3271b..cb6b22b32e63350 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -22537,10 +22537,12 @@ TEST_F(FormatTest, FormatsLambdas) {
                "  }\n"
                "}",
                Style);
-  verifyFormat("std::sort(v.begin(), v.end(),\n"
-               "          [](const auto &foo, const auto &bar) {\n"
-               "  return foo.baz < bar.baz;\n"
-               "});",
+  verifyFormat("void test() {\n"
+               "  std::sort(v.begin(), v.end(),\n"
+               "            [](const auto &foo, const auto &bar) {\n"
+               "    return foo.baz < bar.baz;\n"
+               "  });\n"
+               "};",
                Style);
   verifyFormat("void test() {\n"
                "  (\n"
@@ -22589,9 +22591,23 @@ TEST_F(FormatTest, FormatsLambdas) {
   verifyFormat("Namespace::Foo::Foo(LongClassName bar,\n"
                "                    AnotherLongClassName baz)\n"
                "    : baz{baz}, func{[&] {\n"
-               "  auto qux = bar;\n"
-               "  return aFunkyFunctionCall(qux);\n"
-               "}} {}",
+               "        auto qux = bar;\n"
+               "        return aFunkyFunctionCall(qux);\n"
+               "      }} {}",
+               Style);
+  verifyFormat("void foo() {\n"
+               "  class Foo {\n"
+               "  public:\n"
+               "    Foo()\n"
+               "        : qux{[](int quux) {\n"
+               "            auto tmp = quux;\n"
+               "            return tmp;\n"
+               "          }} {}\n"
+               "\n"
+               "  private:\n"
+               "    std::function<void(int quux)> qux;\n"
+               "  };\n"
+               "}\n",
                Style);
   Style.AlignAfterOpenBracket = FormatStyle::BAS_AlwaysBreak;
   // FIXME: The following test should pass, but fails at the time of writing.