Port to new Q_UNREACHABLE_RETURN()

This is a semantic patch using ClangTidyTransformator to convert
sequences of Q_UNREACHABLE() + return into Q_UNREACHABLE_RETURN(),
newly added to qtbase.

    const std::string unr = "unr", val = "val", ret = "ret";
    auto makeUnreachableReturn = cat("Q_UNREACHABLE_RETURN(",
                                    ifBound(val, cat(node(val)), cat("")),
                                    ")");
    auto ignoringSwitchCases = [](auto stmt) {
        return anyOf(stmt, switchCase(subStmt(stmt)));
    };

    makeRule(stmt(ignoringSwitchCases(stmt(isExpandedFromMacro("Q_UNREACHABLE")).bind(unr)),
                  nextStmt(returnStmt(optionally(hasReturnValue(expr().bind(val)))).bind(ret))),
             {changeTo(node(unr), cat(makeUnreachableReturn,
                                      ";")), // TODO: why is the ; lost w/o this?
              changeTo(node(ret), cat(""))},
             cat("use ", makeUnreachableReturn));

a.k.a qt-use-unreachable-return.

subStmt() and nextStmt() are non-standard matchers.

There was one false positive, suppressed it with NOLINTNEXTLINE.

It's not really a false positiive, it's just that Clang sees the world
in one way and if conditonal compilation (#if) differs for other
compilers, Clang doesn't know better. This is an artifact of matching
two consecutive statements.

Change-Id: I3855b2dc8523db1ea860f72ad9818738162495c6
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 3 insertions, 6 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 8ed900e9e1..fbaf34abe1 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -483,8 +483,7 @@ QString IRBuilder::signalNameFromSignalPropertyName(const QString &signalPropert
         }
     }
 
-    Q_UNREACHABLE();
-    return QString();
+    Q_UNREACHABLE_RETURN(QString());
 }
 
 bool IRBuilder::visit(QQmlJS::AST::UiArrayMemberList *ast)
@@ -803,8 +802,7 @@ private:
             return Pragma::FunctionSignatureBehavior;
         }
 
-        Q_UNREACHABLE();
-        return Pragma::PragmaType(-1);
+        Q_UNREACHABLE_RETURN(Pragma::PragmaType(-1));
     }
 
     static bool assign(Pragma *pragma, QStringView value)
@@ -869,8 +867,7 @@ private:
         default:
             break;
         }
-        Q_UNREACHABLE();
-        return QLatin1StringView();
+        Q_UNREACHABLE_RETURN(QLatin1StringView());
     }
 };