CppEditor: Fix "move function definition"

... for member functions with exception specification and/or reference
qualifiers.
The FunctionDeclaratorAST::cv_qualifier_list member can contain both the
proper qualifiers "const" and "volatile" as well as the pseudo-qualifiers
"override" and "final". The problem is that the former appear before
exception specification and reference qualifiers, whereas the latter come
afterwards. Therefore, when calculating the declarator's first and last
tokens, we can't just mechanically check the different declarator members
in order. Instead, we need to compare the token values to see which
comes first.

Task-number: QTCREATORBUG-27132
Change-Id: I924f9afe49453fa51b4a2fe010d1cc00c9defad1
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

1 files changed, 32 insertions, 23 deletions

diff --git a/src/libs/3rdparty/cplusplus/AST.cpp b/src/libs/3rdparty/cplusplus/AST.cpp
index a48067ab75..360918d2af 100644
--- a/src/libs/3rdparty/cplusplus/AST.cpp
+++ b/src/libs/3rdparty/cplusplus/AST.cpp
@@ -1393,7 +1393,6 @@ int ForeachStatementAST::lastToken() const
     return 1;
 }
 
-/** \generated */
 int FunctionDeclaratorAST::firstToken() const
 {
     if (lparen_token)
@@ -1403,40 +1402,50 @@ int FunctionDeclaratorAST::firstToken() const
             return candidate;
     if (rparen_token)
         return rparen_token;
-    if (cv_qualifier_list)
-        if (int candidate = cv_qualifier_list->firstToken())
-            return candidate;
-    if (ref_qualifier_token)
+    const int firstQualListToken = cv_qualifier_list ? cv_qualifier_list->firstToken() : 0;
+    const auto isBeforeFirstQualListToken = [firstQualListToken](int token) {
+        return token && (!firstQualListToken || token < firstQualListToken);
+    };
+    if (isBeforeFirstQualListToken(ref_qualifier_token))
         return ref_qualifier_token;
-    if (exception_specification)
-        if (int candidate = exception_specification->firstToken())
-            return candidate;
-    if (trailing_return_type)
-        if (int candidate = trailing_return_type->firstToken())
-            return candidate;
+    if (exception_specification) {
+        const int candidate = exception_specification->firstToken();
+        if (isBeforeFirstQualListToken(candidate))
+            return candidate;
+    }
+    if (trailing_return_type) {
+        const int candidate = trailing_return_type->firstToken();
+        if (isBeforeFirstQualListToken(candidate))
+            return candidate;
+    }
+    if (firstQualListToken)
+        return firstQualListToken;
     if (as_cpp_initializer)
         if (int candidate = as_cpp_initializer->firstToken())
             return candidate;
     return 0;
 }
 
-/** \generated */
 int FunctionDeclaratorAST::lastToken() const
 {
     if (as_cpp_initializer)
         if (int candidate = as_cpp_initializer->lastToken())
             return candidate;
-    if (trailing_return_type)
-        if (int candidate = trailing_return_type->lastToken())
-            return candidate;
-    if (exception_specification)
-        if (int candidate = exception_specification->lastToken())
-            return candidate;
-    if (ref_qualifier_token)
-        return ref_qualifier_token + 1;
-    if (cv_qualifier_list)
-        if (int candidate = cv_qualifier_list->lastToken())
-            return candidate;
+    const int lastQualListToken = cv_qualifier_list ? cv_qualifier_list->lastToken() : 0;
+    const auto tokenOrLastQualListToken = [lastQualListToken](int token) {
+        return std::max(token ? token + 1 : 0, lastQualListToken);
+    };
+    const auto tokenFromAstOrLastQualListToken = [lastQualListToken](const AST *ast) {
+        return std::max(ast ? ast->lastToken() : 0, lastQualListToken);
+    };
+    if (int candidate = tokenFromAstOrLastQualListToken(trailing_return_type))
+        return candidate;
+    if (int candidate = tokenFromAstOrLastQualListToken(exception_specification))
+        return candidate;
+    if (int candidate = tokenOrLastQualListToken(ref_qualifier_token))
+        return candidate;
+    if (lastQualListToken)
+        return lastQualListToken;
     if (rparen_token)
         return rparen_token + 1;
     if (parameter_declaration_clause)