QDoc: Use range-based for instead of foreach

This change replaces the use of foreach with range-based for throughout
QDoc. It also ensures that the loop body doesn't modify the container
being iterated over, by:

  - Making a const copy when the container is a member variable or the
    result of an expression, and iterating over that copy. This is the
    preferred approach.
  - Using qAsConst() when the container is a (static) member variable
    or local to the method and not const. The latter is typical where
    the collection is sorted immediately before the loop.

In two cases (doc.cpp), replaced Q_FOREACH + delete with qDeleteAll.

In two cases (cppcodeparser.cpp), the range declaration is replaced
within the loop statement. These rewrites express the behavior clearer
than the original code.

In two cases (codeparser.cpp), use a range-based for instead of a while
loop where the condition is an iterator, for more expressive code.

Finally, use the auto keyword where appropriate and improve a few
variable names.

QDoc warning count and generated output is unchanged after this
refactoring.

Change-Id: I64f02d24dca373a3a41402d535382e2c526bb55e
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/qdoc/cppcodemarker.cpp b/src/qdoc/cppcodemarker.cpp
index 26a43794d..a59654cfa 100644
--- a/src/qdoc/cppcodemarker.cpp
+++ b/src/qdoc/cppcodemarker.cpp
@@ -245,11 +245,12 @@ QString CppCodeMarker::markedUpSynopsis(const Node *node,
 
             QStringList documentedItems = enume->doc().enumItemNames();
             if (documentedItems.isEmpty()) {
-                foreach (const EnumItem &item, enume->items())
+                const auto enumItems = enume->items();
+                for (const auto &item : enumItems)
                     documentedItems << item.name();
             }
-            QStringList omitItems = enume->doc().omitEnumItemNames();
-            foreach (const QString &item, omitItems)
+            const QStringList omitItems = enume->doc().omitEnumItemNames();
+            for (const auto &item : omitItems)
                 documentedItems.removeAll(item);
 
             if (documentedItems.size() <= MaxEnumValues) {