Clang: Improve function definition completion

Insert argument list together with completion.

Task-number: QTCREATORBUG-20826
Change-Id: I4aa9faaa04bcd3ca014306aad27843c2b4419d3c
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

src/libs/clangsupport/codecompletion.h

@@ -45,6 +45,7 @@ public:
     enum Kind : quint32 {
         Other = 0,
         FunctionCompletionKind,
+        FunctionDefinitionCompletionKind,
         FunctionOverloadCompletionKind,
         TemplateFunctionCompletionKind,
         ConstructorCompletionKind,

src/plugins/clangcodemodel/clangassistproposalitem.cpp

@@ -164,6 +164,7 @@ void ClangAssistProposalItem::apply(TextEditor::TextDocumentManipulatorInterface
 
         if (autoInsertBrackets &&
                 (ccr.completionKind == CodeCompletion::FunctionCompletionKind
+                 || ccr.completionKind == CodeCompletion::FunctionDefinitionCompletionKind
                  || ccr.completionKind == CodeCompletion::DestructorCompletionKind
                  || ccr.completionKind == CodeCompletion::SignalCompletionKind
                  || ccr.completionKind == CodeCompletion::SlotCompletionKind)) {
@@ -176,17 +177,40 @@ void ClangAssistProposalItem::apply(TextEditor::TextDocumentManipulatorInterface
             while (manipulator.characterAt(cursor.position()) == ':')
                 cursor.movePosition(QTextCursor::PreviousWord, QTextCursor::MoveAnchor, 2);
 
+            const int previousWordStart = cursor.position();
             // Move to the last character in the previous word
             cursor.movePosition(QTextCursor::NextWord);
             moveToPrevChar(manipulator, cursor);
+            const QString previousWord = manipulator.textAt(previousWordStart,
+                                                            cursor.position() - previousWordStart + 1);
+
             bool abandonParen = false;
-            if (manipulator.characterAt(cursor.position()) == '&') {
+            if (previousWord == "&") {
                 moveToPrevChar(manipulator, cursor);
                 const QChar prevChar = manipulator.characterAt(cursor.position());
                 abandonParen = QString("(;,{}").contains(prevChar);
             }
             if (!abandonParen)
                 abandonParen = isAtUsingDeclaration(manipulator, basePosition);
+            if (!abandonParen && ccr.completionKind == CodeCompletion::FunctionDefinitionCompletionKind) {
+                const CodeCompletionChunk resultType = ccr.chunks.first();
+                QTC_ASSERT(resultType.kind == CodeCompletionChunk::ResultType, return;);
+                if (previousWord == resultType.text.toString()) {
+                    bool skipChunks = true;
+                    for (const CodeCompletionChunk &chunk : ccr.chunks) {
+                        if (chunk.kind == CodeCompletionChunk::TypedText) {
+                            skipChunks = false;
+                            continue;
+                        }
+                        if (skipChunks)
+                            continue;
+                        extraCharacters += chunk.text;
+                    }
+
+                    // To skip the next block.
+                    abandonParen = true;
+                }
+            }
             if (!abandonParen) {
                 if (completionSettings.m_spaceAfterFunctionName)
                     extraCharacters += QLatin1Char(' ');
@@ -338,6 +362,7 @@ QIcon ClangAssistProposalItem::icon() const
         case CodeCompletion::ConstructorCompletionKind:
         case CodeCompletion::DestructorCompletionKind:
         case CodeCompletion::FunctionCompletionKind:
+        case CodeCompletion::FunctionDefinitionCompletionKind:
         case CodeCompletion::TemplateFunctionCompletionKind:
         case CodeCompletion::ObjCMessageCompletionKind:
             switch (m_codeCompletion.availability) {

src/tools/clangbackend/source/clangcodecompleteresults.cpp

@@ -56,24 +56,12 @@ bool ClangCodeCompleteResults::hasResults() const
     return !isNull() && !isEmpty();
 }
 
-bool ClangCodeCompleteResults::hasNoResultsForDotCompletion() const
-{
-    return !hasResults() && isDotCompletion();
-}
-
 bool ClangCodeCompleteResults::hasUnknownContext() const
 {
     const unsigned long long contexts = clang_codeCompleteGetContexts(cxCodeCompleteResults);
     return contexts == CXCompletionContext_Unknown;
 }
 
-bool ClangCodeCompleteResults::isDotCompletion() const
-{
-    const unsigned long long contexts = clang_codeCompleteGetContexts(cxCodeCompleteResults);
-
-    return contexts & CXCompletionContext_DotMemberAccess;
-}
-
 CXCodeCompleteResults *ClangCodeCompleteResults::data() const
 {
     return cxCodeCompleteResults;

src/tools/clangbackend/source/clangcodecompleteresults.h

@@ -49,10 +49,8 @@ public:
     bool isEmpty() const;
 
     bool hasResults() const;
-    bool hasNoResultsForDotCompletion() const;
 
     bool hasUnknownContext() const;
-    bool isDotCompletion() const;
 
     CXCodeCompleteResults *data() const;
 

src/tools/clangbackend/source/codecompletionsextractor.cpp

@@ -176,6 +176,9 @@ void CodeCompletionsExtractor::extractText()
 void CodeCompletionsExtractor::extractMethodCompletionKind()
 {
     CXCompletionString cxCompletionString = cxCodeCompleteResults->Results[cxCodeCompleteResultIndex].CompletionString;
+
+    const unsigned long long contexts = clang_codeCompleteGetContexts(cxCodeCompleteResults);
+
     const uint annotationCount = clang_getCompletionNumAnnotations(cxCompletionString);
 
     for (uint annotationIndex = 0; annotationIndex < annotationCount; ++annotationIndex) {
@@ -192,7 +195,11 @@ void CodeCompletionsExtractor::extractMethodCompletionKind()
         }
     }
 
+    currentCodeCompletion_.completionKind = CodeCompletion::FunctionDefinitionCompletionKind;
+    if ((contexts & CXCompletionContext_DotMemberAccess)
+            || (contexts & CXCompletionContext_ArrowMemberAccess)) {
         currentCodeCompletion_.completionKind = CodeCompletion::FunctionCompletionKind;
+    }
 }
 
 void CodeCompletionsExtractor::extractMacroCompletionKind()