Support C++17 fallthrough attribute

Replaces our mix of comments for annotating intended absence of break
in switches with the C++17 attribute [[fallthrough]], or its earlier
a clang extension counterpart.

Change-Id: I4b2d0b9b5e4425819c7f1bf01608093c536b6d14
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 19 insertions, 19 deletions

diff --git a/src/corelib/xml/qxmlstream.cpp b/src/corelib/xml/qxmlstream.cpp
index 83b26d50ab..1ffaeca852 100644
--- a/src/corelib/xml/qxmlstream.cpp
+++ b/src/corelib/xml/qxmlstream.cpp
@@ -976,11 +976,11 @@ bool QXmlStreamReaderPrivate::scanUntil(const char *str, short tokenToInject)
         case '\r':
             if ((c = filterCarriageReturn()) == 0)
                 break;
-            // fall through
+            Q_FALLTHROUGH();
         case '\n':
             ++lineNumber;
             lastLineStart = characterOffset + readBufferPos;
-            // fall through
+            Q_FALLTHROUGH();
         case '\t':
             textBuffer += QChar(c);
             continue;
@@ -1158,11 +1158,11 @@ inline int QXmlStreamReaderPrivate::fastScanLiteralContent()
         case '\r':
             if (filterCarriageReturn() == 0)
                 return n;
-            // fall through
+            Q_FALLTHROUGH();
         case '\n':
             ++lineNumber;
             lastLineStart = characterOffset + readBufferPos;
-            // fall through
+            Q_FALLTHROUGH();
         case ' ':
         case '\t':
             if (normalizeLiterals)
@@ -1179,7 +1179,7 @@ inline int QXmlStreamReaderPrivate::fastScanLiteralContent()
                 putChar(c);
                 return n;
             }
-            // fall through
+            Q_FALLTHROUGH();
         default:
             if (c < 0x20) {
                 putChar(c);
@@ -1201,11 +1201,11 @@ inline int QXmlStreamReaderPrivate::fastScanSpace()
         case '\r':
             if ((c = filterCarriageReturn()) == 0)
                 return n;
-            // fall through
+            Q_FALLTHROUGH();
         case '\n':
             ++lineNumber;
             lastLineStart = characterOffset + readBufferPos;
-            // fall through
+            Q_FALLTHROUGH();
         case ' ':
         case '\t':
             textBuffer += QChar(c);
@@ -1259,11 +1259,11 @@ inline int QXmlStreamReaderPrivate::fastScanContentCharList()
         case '\r':
             if ((c = filterCarriageReturn()) == 0)
                 return n;
-            // fall through
+            Q_FALLTHROUGH();
         case '\n':
             ++lineNumber;
             lastLineStart = characterOffset + readBufferPos;
-            // fall through
+            Q_FALLTHROUGH();
         case ' ':
         case '\t':
             textBuffer += QChar(ushort(c));
@@ -1275,7 +1275,7 @@ inline int QXmlStreamReaderPrivate::fastScanContentCharList()
                 putChar(c);
                 return n;
             }
-            // fall through
+            Q_FALLTHROUGH();
         default:
             if (c < 0x20) {
                 putChar(c);
@@ -1339,7 +1339,7 @@ inline int QXmlStreamReaderPrivate::fastScanName(int *prefix)
                 putChar(c);
                 return n;
             }
-            // fall through
+            Q_FALLTHROUGH();
         default:
             textBuffer += QChar(c);
             ++n;
@@ -2123,7 +2123,7 @@ QString QXmlStreamReader::readElementText(ReadElementTextBehaviour behaviour)
                     result += readElementText(behaviour);
                     break;
                 }
-                // Fall through (for ErrorOnUnexpectedElement)
+                Q_FALLTHROUGH();
             default:
                 if (d->error || behaviour == ErrorOnUnexpectedElement) {
                     if (!d->error)
diff --git a/src/corelib/xml/qxmlstream_p.h b/src/corelib/xml/qxmlstream_p.h
index c68d6f0f53..b62cc9ac39 100644
--- a/src/corelib/xml/qxmlstream_p.h
+++ b/src/corelib/xml/qxmlstream_p.h
@@ -1048,7 +1048,7 @@ bool QXmlStreamReaderPrivate::parse()
         dtdName.clear();
         dtdPublicId.clear();
         dtdSystemId.clear();
-        // fall through
+        Q_FALLTHROUGH();
     case QXmlStreamReader::Comment:
     case QXmlStreamReader::Characters:
         isCDATA = false;
@@ -1080,7 +1080,7 @@ bool QXmlStreamReaderPrivate::parse()
             return false;
         }
 #endif
-        // fall through
+        Q_FALLTHROUGH();
     default:
         clearTextBuffer();
         ;
@@ -1124,7 +1124,7 @@ bool QXmlStreamReaderPrivate::parse()
                 } else {
                     break;
                 }
-                // fall through
+                Q_FALLTHROUGH();
             case ~0U: {
                 token = EOF_SYMBOL;
                 if (!tagsDone && !inParseEntity) {
@@ -1338,7 +1338,7 @@ bool QXmlStreamReaderPrivate::parse()
         case 17:
         case 18:
             dtdName = symString(3);
-            // fall through
+            Q_FALLTHROUGH();
 
         case 19:
         case 20:
@@ -1480,7 +1480,7 @@ bool QXmlStreamReaderPrivate::parse()
             if (entityDeclaration.parameter)
                 raiseWellFormedError(QXmlStream::tr("NDATA in parameter entity declaration."));
         }
-        //fall through
+        Q_FALLTHROUGH();
 
         case 94:
         case 95: {
@@ -1588,7 +1588,7 @@ bool QXmlStreamReaderPrivate::parse()
 
         case 129:
             isWhitespace = false;
-            // fall through
+            Q_FALLTHROUGH();
 
         case 130:
             sym(1).len += fastScanContentCharList();
@@ -1760,7 +1760,7 @@ bool QXmlStreamReaderPrivate::parse()
 
         case 236:
             isEmptyElement = true;
-        // fall through
+            Q_FALLTHROUGH();
 
         case 237:
             setType(QXmlStreamReader::StartElement);