Moc: parse trailing return type

Pick-to: 5.15 6.1
Fixes: QTBUG-71123
Change-Id: I1c3749f0892fddcc433c9afcb1d6d7c30c97c9d9
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 21 insertions, 9 deletions

diff --git a/src/tools/moc/moc.cpp b/src/tools/moc/moc.cpp
index a66eda6f86..c8fe0e9a83 100644
--- a/src/tools/moc/moc.cpp
+++ b/src/tools/moc/moc.cpp
@@ -198,6 +198,7 @@ Type Moc::parseType()
         case DOUBLE:
         case VOID:
         case BOOL:
+        case AUTO:
             type.name += lexem();
             isVoid |= (lookup(0) == VOID);
             break;
@@ -467,15 +468,6 @@ bool Moc::parseFunction(FunctionDef *def, bool inMacro)
         scopedFunctionName = tempType.isScoped;
     }
 
-    // we don't support references as return types, it's too dangerous
-    if (def->type.referenceType == Type::Reference) {
-        QByteArray rawName = def->type.rawName;
-        def->type = Type("void");
-        def->type.rawName = rawName;
-    }
-
-    def->normalizedType = normalizeType(def->type.name);
-
     if (!test(RPAREN)) {
         parseFunctionArguments(def);
         next(RPAREN);
@@ -498,6 +490,10 @@ bool Moc::parseFunction(FunctionDef *def, bool inMacro)
             next(LPAREN);
             until(RPAREN);
         }
+
+        if (def->type.name == "auto" && test(ARROW))
+            def->type = parseType(); // Parse trailing return-type
+
         if (test(SEMIC))
             ;
         else if ((def->inlineCode = test(LBRACE)))
@@ -515,6 +511,22 @@ bool Moc::parseFunction(FunctionDef *def, bool inMacro)
         warning(msg.constData());
         return false;
     }
+
+    QList<QByteArray> typeNameParts = normalizeType(def->type.name).split(' ');
+    if (typeNameParts.contains("auto")) {
+        // We expected a trailing return type but we haven't seen one
+        error("Function declared with auto as return type but missing trailing return type. "
+              "Return type deduction is not supported.");
+    }
+
+    // we don't support references as return types, it's too dangerous
+    if (def->type.referenceType == Type::Reference) {
+        QByteArray rawName = def->type.rawName;
+        def->type = Type("void");
+        def->type.rawName = rawName;
+    }
+
+    def->normalizedType = normalizeType(def->type.name);
     return true;
 }