[clang-format] Fix a bug in breaking before FunctionDeclarationName (#153924)

Fixes #153891

Author: owenca

clang/lib/Format/ContinuationIndenter.cpp

@@ -629,9 +629,16 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
       // name.
       !Style.isJavaScript() && Previous.isNot(tok::kw_template) &&
       CurrentState.BreakBeforeParameter) {
-    for (const auto *Tok = &Previous; Tok; Tok = Tok->Previous)
-      if (Tok->FirstAfterPPLine || Tok->is(TT_LineComment))
+    for (const auto *Tok = &Previous; Tok; Tok = Tok->Previous) {
+      if (Tok->is(TT_LineComment))
         return false;
+      if (Tok->is(TT_TemplateCloser)) {
+        Tok = Tok->MatchingParen;
+        assert(Tok);
+      }
+      if (Tok->FirstAfterPPLine)
+        return false;
+    }
 
     return true;
   }

clang/unittests/Format/FormatTest.cpp

@@ -8618,14 +8618,22 @@ TEST_F(FormatTest, BreaksFunctionDeclarations) {
   verifyFormat("extern \"C\" //\n"
                "    void f();");
 
-  FormatStyle Style = getLLVMStyle();
+  auto Style = getLLVMStyle();
   Style.PointerAlignment = FormatStyle::PAS_Left;
   verifyFormat("void aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
                "    aaaaaaaaaaaaaaaaaaaaaaaaa* const aaaaaaaaaaaa) {}",
                Style);
   verifyFormat("void aaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa*\n"
                "                 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) {}",
                Style);
+
+  Style = getLLVMStyleWithColumns(45);
+  Style.PenaltyReturnTypeOnItsOwnLine = 400;
+  verifyFormat("template <bool abool, // a comment\n"
+               "          bool anotherbool>\n"
+               "static inline std::pair<size_t, MyCustomType>\n"
+               "myfunc(const char *buf, const char *&err);",
+               Style);
 }
 
 TEST_F(FormatTest, DontBreakBeforeQualifiedOperator) {