[clang-format] Stop moving lambda to new line only to indent it more.

clang/lib/Format/ContinuationIndenter.cpp

@@ -325,13 +325,35 @@ bool ContinuationIndenter::canBreak(const LineState &State) {
   if (Current.isMemberAccess() && CurrentState.ContainsUnwrappedBuilder)
     return false;
 
-  // Don't create a 'hanging' indent if there are multiple blocks in a single
-  // statement and we are aligning lambda blocks to their signatures.
+  // Force a lambda onto a new line so that we don't create a 'hanging' indent
+  // if there are multiple blocks in a single statement and we are aligning
+  // lambda blocks to their signatures.
   if (Previous.is(tok::l_brace) && State.Stack.size() > 1 &&
       State.Stack[State.Stack.size() - 2].NestedBlockInlined &&
       State.Stack[State.Stack.size() - 2].HasMultipleNestedBlocks) {
-    return Style.isCpp() &&
-           Style.LambdaBodyIndentation == FormatStyle::LBI_OuterScope;
+    if (!Style.isCpp())
+      return false;
+
+    if (Style.LambdaBodyIndentation == FormatStyle::LBI_OuterScope)
+      return true;
+
+    // Make sure to push lambdas to a new line when they are an argument with
+    // other arguments preceding them.
+    if (State.Stack[State.Stack.size() - 2].StartOfFunctionCall > 0)
+      return false;
+
+    // Only force a new line if it is not just going to create a worse hanging
+    // indent. Otherwise, based on the ContinuationIndentWidth, we could end up
+    // more indented than we would've been. To avoid odd looking breaks, make
+    // sure we save at least IndentWidth.
+    if (State.Stack.size() > 2 &&
+        State.Stack[State.Stack.size() - 3].Indent +
+                Style.ContinuationIndentWidth + Style.IndentWidth <
+            State.Stack[State.Stack.size() - 2].Indent) {
+      return false;
+    }
+
+    return true;
   }
 
   // Don't break after very short return types (e.g. "void") as that is often

clang/unittests/Format/FormatTest.cpp

@@ -23813,6 +23813,17 @@ TEST_F(FormatTest, FormatsLambdas) {
                "          }};\n"
                "}",
                LLVMWithBeforeLambdaBody);
+  verifyFormat("if ([]()\n"
+               "    {\n"
+               "      return true;\n"
+               "    }()) {\n"
+               "}",
+               LLVMWithBeforeLambdaBody);
+  verifyFormat("fun([]()\n"
+               "    {\n"
+               "      return 17;\n"
+               "    });",
+               LLVMWithBeforeLambdaBody);
 
   LLVMWithBeforeLambdaBody.AllowShortLambdasOnASingleLine =
       FormatStyle::ShortLambdaStyle::SLS_Empty;