diff --git a/src/plugins/debugger/breakwindow.cpp b/src/plugins/debugger/breakwindow.cpp
index b142b52b1d9..7bf1fb58bba 100644
--- a/src/plugins/debugger/breakwindow.cpp
+++ b/src/plugins/debugger/breakwindow.cpp
@@ -96,7 +96,7 @@ private:
 };
 
 BreakpointDialog::BreakpointDialog(BreakpointModelId id, QWidget *parent)
-    : QDialog(parent), m_enabledParts(-1), m_previousType(UnknownType),
+    : QDialog(parent), m_enabledParts(~0), m_previousType(UnknownType),
       m_firstTypeChange(true)
 {
     m_ui.setupUi(this);
diff --git a/src/plugins/debugger/cdb/cdbengine.cpp b/src/plugins/debugger/cdb/cdbengine.cpp
index ff603fe23b5..4b2864633a3 100644
--- a/src/plugins/debugger/cdb/cdbengine.cpp
+++ b/src/plugins/debugger/cdb/cdbengine.cpp
@@ -844,7 +844,7 @@ void CdbEngine::setupInferior()
     if (startParameters().breakOnMain) {
         const BreakpointParameters bp(BreakpointAtMain);
         postCommand(cdbAddBreakpointCommand(bp, m_sourcePathMappings,
-                                            BreakpointModelId(-1), true), 0);
+                                            BreakpointModelId(quint16(-1)), true), 0);
     }
     postCommand("sxn 0x4000001f", 0); // Do not break on WowX86 exceptions.
     postCommand(".asm source_line", 0); // Source line in assembly
@@ -1209,7 +1209,7 @@ void CdbEngine::executeRunToLine(const ContextData &data)
         bp.fileName = data.fileName;
         bp.lineNumber = data.lineNumber;
     }
-    postCommand(cdbAddBreakpointCommand(bp, m_sourcePathMappings, BreakpointModelId(-1), true), 0);
+    postCommand(cdbAddBreakpointCommand(bp, m_sourcePathMappings, BreakpointModelId(quint16(-1)), true), 0);
     continueInferior();
 }
 
@@ -1219,7 +1219,7 @@ void CdbEngine::executeRunToFunction(const QString &functionName)
     BreakpointParameters bp(BreakpointByFunction);
     bp.functionName = functionName;
 
-    postCommand(cdbAddBreakpointCommand(bp, m_sourcePathMappings, BreakpointModelId(-1), true), 0);
+    postCommand(cdbAddBreakpointCommand(bp, m_sourcePathMappings, BreakpointModelId(quint16(-1)), true), 0);
     continueInferior();
 }
 
diff --git a/src/plugins/debugger/cdb/cdbparsehelpers.h b/src/plugins/debugger/cdb/cdbparsehelpers.h
index ea052c9b9ee..cf310567c9f 100644
--- a/src/plugins/debugger/cdb/cdbparsehelpers.h
+++ b/src/plugins/debugger/cdb/cdbparsehelpers.h
@@ -65,7 +65,7 @@ QString cdbSourcePathMapping(QString fileName,
 // Convert breakpoint in CDB syntax (applying source path mappings using native paths).
 QByteArray cdbAddBreakpointCommand(const BreakpointParameters &d,
                                    const QList<QPair<QString, QString> > &sourcePathMapping,
-                                   BreakpointModelId id = BreakpointModelId(-1), bool oneshot = false);
+                                   BreakpointModelId id = BreakpointModelId(quint16(-1)), bool oneshot = false);
 // Parse extension command listing breakpoints.
 // Note that not all fields are returned, since file, line, function are encoded
 // in the expression (that is in addition deleted on resolving for a bp-type breakpoint).
diff --git a/src/plugins/debugger/lldb/ipcengineguest.h b/src/plugins/debugger/lldb/ipcengineguest.h
index 4a5eb88a5bc..242a3e5d910 100644
--- a/src/plugins/debugger/lldb/ipcengineguest.h
+++ b/src/plugins/debugger/lldb/ipcengineguest.h
@@ -152,8 +152,8 @@ public:
     void notifyInferiorIll();
     void notifyEngineIll();
     void notifyInferiorPid(qint64 pid);
-    void showMessage(const QString &msg, quint16 channel = LogDebug, quint64 timeout = -1);
-    void showStatusMessage(const QString &msg, quint64 timeout = -1);
+    void showMessage(const QString &msg, quint16 channel = LogDebug, quint64 timeout = quint64(-1));
+    void showStatusMessage(const QString &msg, quint64 timeout = quint64(-1));
 
     void currentFrameChanged(qint64 token);
     void currentThreadChanged(qint64 token);
diff --git a/src/plugins/glsleditor/glsleditorplugin.cpp b/src/plugins/glsleditor/glsleditorplugin.cpp
index 769ad54fee8..cc1244b39de 100644
--- a/src/plugins/glsleditor/glsleditorplugin.cpp
+++ b/src/plugins/glsleditor/glsleditorplugin.cpp
@@ -278,7 +278,7 @@ QByteArray GLSLEditorPlugin::glslFile(const QString &fileName) const
 void GLSLEditorPlugin::parseGlslFile(const QString &fileName, InitFile *initFile) const
 {
     // Parse the builtins for any langugage variant so we can use all keywords.
-    const unsigned variant = GLSL::Lexer::Variant_All;
+    const int variant = GLSL::Lexer::Variant_All;
 
     const QByteArray code = glslFile(fileName);
     initFile->engine = new GLSL::Engine();
diff --git a/src/plugins/texteditor/refactoringchanges.cpp b/src/plugins/texteditor/refactoringchanges.cpp
index 0db20597ada..9ef23a465c3 100644
--- a/src/plugins/texteditor/refactoringchanges.cpp
+++ b/src/plugins/texteditor/refactoringchanges.cpp
@@ -330,7 +330,7 @@ void RefactoringFile::apply()
 {
     // open / activate / goto position
     if (m_openEditor && !m_fileName.isEmpty()) {
-        unsigned line = -1, column = -1;
+        unsigned line = unsigned(-1), column = unsigned(-1);
         if (m_editorCursorPosition != -1)
             lineAndColumn(m_editorCursorPosition, &line, &column);
         m_editor = RefactoringChanges::openEditor(m_fileName, m_activateEditor, line, column);