diff --git a/src/AudacityApp.cpp b/src/AudacityApp.cpp
index 0f03fdb13..5a78bbaf7 100644
--- a/src/AudacityApp.cpp
+++ b/src/AudacityApp.cpp
@@ -1875,9 +1875,9 @@ bool AudacityApp::CreateSingleInstanceChecker(const wxString &dir)
             if (parser->GetParamCount() > 0)
             {
                // Send each parameter to existing Audacity
-               for (size_t i = 0, cnt = parser->GetParamCount(); i < cnt; i++)
+               for (size_t j = 0, cnt = parser->GetParamCount(); j < cnt; j++)
                {
-                  ok = conn->Execute(parser->GetParam(i));
+                  ok = conn->Execute(parser->GetParam(j));
                }
              }
             else
diff --git a/src/DirManager.cpp b/src/DirManager.cpp
index 138876de5..41900141a 100644
--- a/src/DirManager.cpp
+++ b/src/DirManager.cpp
@@ -611,7 +611,7 @@ bool DirManager::SetProject(wxString& newProjPath, wxString& newProjName, const
             if (b) {
                if (moving || !b->IsLocked()) {
                   auto result = b->GetFileName();
-                  auto oldPath = result.name.GetFullPath();
+                  oldPath = result.name.GetFullPath();
                   if (!oldPath.empty())
                      wxRemoveFile( oldPath );
                }
@@ -945,7 +945,7 @@ void DirManager::BalanceInfoDel(const wxString &file)
                if(--dirTopPool[topnum]<1){
                   // do *not* erase the hash entry from dirTopPool
                   // *do* DELETE the actual directory
-                  wxString dir=(projFull != wxT("")? projFull: mytemp);
+                  dir=(projFull != wxT("")? projFull: mytemp);
                   dir += wxFILE_SEP_PATH;
                   dir += file.Mid(0,3);
                   wxFileName::Rmdir(dir);
@@ -1506,10 +1506,10 @@ bool DirManager::EnsureSafeFilename(const wxFileName &fName)
       else
       {
          //point the aliases to the NEW filename.
-         BlockHash::iterator iter = mBlockFileHash.begin();
-         while (iter != mBlockFileHash.end())
+         BlockHash::iterator iter2 = mBlockFileHash.begin();
+         while (iter2 != mBlockFileHash.end())
          {
-            BlockFilePtr b = iter->second.lock();
+            BlockFilePtr b = iter2->second.lock();
             if (b) {
                auto ab = static_cast< AliasBlockFile * > ( &*b );
                auto db = static_cast< ODDecodeBlockFile * > ( &*b );
@@ -1525,7 +1525,7 @@ bool DirManager::EnsureSafeFilename(const wxFileName &fName)
                   db->ChangeAudioFile(wxFileNameWrapper{ renamedFileName });
                }
             }
-            ++iter;
+            ++iter2;
          }
 
       }
diff --git a/src/Dither.cpp b/src/Dither.cpp
index 4f9569061..79a451774 100644
--- a/src/Dither.cpp
+++ b/src/Dither.cpp
@@ -174,11 +174,11 @@ const float Dither::SHAPED_BS[] = { 2.033f, -2.165f, 1.959f, -1.590f, 0.6149f };
 #define DITHER_LOOP(dither, store, load, dst, dstFormat, dstStride, src, srcFormat, srcStride, len) \
     do { \
        char *d, *s; \
-       unsigned int i; \
+       unsigned int ii; \
        int x; \
-       for (d = (char*)dst, s = (char*)src, i = 0; \
-            i < len; \
-            i++, d += SAMPLE_SIZE(dstFormat) * dstStride, \
+       for (d = (char*)dst, s = (char*)src, ii = 0; \
+            ii < len; \
+            ii++, d += SAMPLE_SIZE(dstFormat) * dstStride, \
                  s += SAMPLE_SIZE(srcFormat) * srcStride) \
           DITHER_STEP(dither, store, load, d, s); \
    } while (0)
diff --git a/src/Menus.cpp b/src/Menus.cpp
index 07a0cc1c9..54b9fe939 100644
--- a/src/Menus.cpp
+++ b/src/Menus.cpp
@@ -6858,15 +6858,19 @@ MenuCommandHandler::FoundClip MenuCommandHandler::FindNextClip
 
    t0 = AdjustForFindingStartTimes(clips, t0);
 
-   auto p = std::find_if(clips.begin(), clips.end(), [&] (const WaveClip* const& clip) {
-      return clip->GetStartTime() == t0; });
-   if (p != clips.end() && (*p)->GetEndTime() > t1) {
-      result.found = true;
-      result.startTime = (*p)->GetStartTime();
-      result.endTime = (*p)->GetEndTime();
-      result.index = std::distance(clips.begin(), p);
+   {
+      auto p = std::find_if(clips.begin(), clips.end(), [&] (const WaveClip* const& clip) {
+         return clip->GetStartTime() == t0; });
+      if (p != clips.end() && (*p)->GetEndTime() > t1) {
+         result.found = true;
+         result.startTime = (*p)->GetStartTime();
+         result.endTime = (*p)->GetEndTime();
+         result.index = std::distance(clips.begin(), p);
+         return result;
+      }
    }
-   else {
+
+   {
       auto p = std::find_if(clips.begin(), clips.end(), [&] (const WaveClip* const& clip) {
          return clip->GetStartTime() > t0; });
       if (p != clips.end()) {
@@ -6874,6 +6878,7 @@ MenuCommandHandler::FoundClip MenuCommandHandler::FindNextClip
          result.startTime = (*p)->GetStartTime();
          result.endTime = (*p)->GetEndTime();
          result.index = std::distance(clips.begin(), p);
+         return result;
       }
    }
 
@@ -6889,15 +6894,19 @@ MenuCommandHandler::FoundClip MenuCommandHandler::FindPrevClip
 
    t0 = AdjustForFindingStartTimes(clips, t0);
 
-   auto p = std::find_if(clips.begin(), clips.end(), [&] (const WaveClip* const& clip) {
-      return clip->GetStartTime() == t0; });
-   if (p != clips.end() && (*p)->GetEndTime() < t1) {
-      result.found = true;
-      result.startTime = (*p)->GetStartTime();
-      result.endTime = (*p)->GetEndTime();
-      result.index = std::distance(clips.begin(), p);
+   {
+      auto p = std::find_if(clips.begin(), clips.end(), [&] (const WaveClip* const& clip) {
+         return clip->GetStartTime() == t0; });
+      if (p != clips.end() && (*p)->GetEndTime() < t1) {
+         result.found = true;
+         result.startTime = (*p)->GetStartTime();
+         result.endTime = (*p)->GetEndTime();
+         result.index = std::distance(clips.begin(), p);
+         return result;
+      }
    }
-   else {
+   
+   {
       auto p = std::find_if(clips.rbegin(), clips.rend(), [&] (const WaveClip* const& clip) {
          return clip->GetStartTime() < t0; });
       if (p != clips.rend()) {
@@ -6905,6 +6914,7 @@ MenuCommandHandler::FoundClip MenuCommandHandler::FindPrevClip
          result.startTime = (*p)->GetStartTime();
          result.endTime = (*p)->GetEndTime();
          result.index = static_cast<int>(clips.size()) - 1 - std::distance(clips.rbegin(), p);
+         return result;
       }
    }
 
@@ -6926,17 +6936,17 @@ int MenuCommandHandler::FindClips
 
    int nTracksSearched = 0;
    auto leaders = tracks->Leaders();
-   auto range = leaders.Filter<const WaveTrack>();
+   auto rangeLeaders = leaders.Filter<const WaveTrack>();
    if (anyWaveTracksSelected)
-      range = range + &Track::GetSelected;
-   for (auto waveTrack : range) {
+      rangeLeaders = rangeLeaders + &Track::GetSelected;
+   for (auto waveTrack : rangeLeaders) {
       bool stereoAndDiff = ChannelsHaveDifferentClipBoundaries(waveTrack);
 
-      auto range = stereoAndDiff
+      auto rangeChans = stereoAndDiff
          ? TrackList::Channels( waveTrack )
          : TrackList::SingletonRange( waveTrack );
 
-      for ( auto wt : range ) {
+      for ( auto wt : rangeChans ) {
          auto result = next ? FindNextClip(project, wt, t0, t1) :
             FindPrevClip(project, wt, t0, t1);
          if (result.found) {
@@ -6957,12 +6967,12 @@ int MenuCommandHandler::FindClips
       auto compareStart = [] (const FoundClip& a, const FoundClip& b)
          { return a.startTime < b.startTime; };
 
-      auto p = next ? std::min_element(results.begin(), results.end(), compareStart) :
+      auto pStart = next ? std::min_element(results.begin(), results.end(), compareStart) :
          std::max_element(results.begin(), results.end(), compareStart);
 
       std::vector<FoundClip> resultsStartTime;
       for ( auto &r : results )
-         if ( r.startTime == (*p).startTime )
+         if ( r.startTime == (*pStart).startTime )
             resultsStartTime.push_back( r );
 
       if (resultsStartTime.size() > 1) {
@@ -6971,13 +6981,13 @@ int MenuCommandHandler::FindClips
          auto compareEnd = [] (const FoundClip& a, const FoundClip& b)
             { return a.endTime < b.endTime; };
 
-         auto p = next ? std::min_element(resultsStartTime.begin(),
+         auto pEnd = next ? std::min_element(resultsStartTime.begin(),
             resultsStartTime.end(), compareEnd) :
             std::max_element(resultsStartTime.begin(),
             resultsStartTime.end(), compareEnd);
 
          for ( auto &r : resultsStartTime )
-            if ( r.endTime == (*p).endTime )
+            if ( r.endTime == (*pEnd).endTime )
                finalResults.push_back( r );
       }
       else {
@@ -8152,17 +8162,17 @@ int MenuCommandHandler::FindClipBoundaries
 
    int nTracksSearched = 0;
    auto leaders = tracks->Leaders();
-   auto range = leaders.Filter<const WaveTrack>();
+   auto rangeLeaders = leaders.Filter<const WaveTrack>();
    if (anyWaveTracksSelected)
-      range = range + &Track::GetSelected;
-   for (auto waveTrack : range) {
+      rangeLeaders = rangeLeaders + &Track::GetSelected;
+   for (auto waveTrack : rangeLeaders) {
       bool stereoAndDiff = ChannelsHaveDifferentClipBoundaries(waveTrack);
 
-      auto range = stereoAndDiff
+      auto rangeChan = stereoAndDiff
          ? TrackList::Channels( waveTrack )
          : TrackList::SingletonRange(waveTrack);
 
-      for (auto wt : range) {
+      for (auto wt : rangeChan) {
          auto result = next ? FindNextClipBoundary(wt, time) :
          FindPrevClipBoundary(wt, time);
          if (result.nFound > 0) {
diff --git a/src/ModuleManager.cpp b/src/ModuleManager.cpp
index 62bec1bcc..d6d273ae6 100755
--- a/src/ModuleManager.cpp
+++ b/src/ModuleManager.cpp
@@ -504,7 +504,7 @@ void ModuleManager::FindAllPlugins(PluginIDList & providers, wxArrayString & pat
       plug = pm.GetNextPlugin(PluginTypeModule);
    }
 
-   for (size_t i = 0, cnt = modIDs.size(); i < cnt; i++)
+   for (size_t i = 0, cntIds = modIDs.size(); i < cntIds; i++)
    {
       PluginID providerID = modIDs[i];
 
@@ -515,10 +515,10 @@ void ModuleManager::FindAllPlugins(PluginIDList & providers, wxArrayString & pat
          continue;
 
       wxArrayString newpaths = module->FindPluginPaths(pm);
-      for (size_t i = 0, cnt = newpaths.size(); i < cnt; i++)
+      for (size_t j = 0, cntPaths = newpaths.size(); j < cntPaths; j++)
       {
          providers.push_back(providerID);
-         paths.push_back(newpaths[i]);
+         paths.push_back(newpaths[j]);
       }
    }
 }
diff --git a/src/PluginManager.cpp b/src/PluginManager.cpp
index 24aef16a5..4e9d3e3d0 100644
--- a/src/PluginManager.cpp
+++ b/src/PluginManager.cpp
@@ -924,11 +924,13 @@ void PluginRegistrationDialog::OnEnable(wxCommandEvent & WXUNUSED(evt))
 {
    std::vector<long> items;
 
-   long i = mEffects->GetNextItem(-1, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
-   while (i != wxNOT_FOUND)
    {
-      items.insert(items.begin(), i);
-      i = mEffects->GetNextItem(i, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
+      long i = mEffects->GetNextItem(-1, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
+      while (i != wxNOT_FOUND)
+      {
+         items.insert(items.begin(), i);
+         i = mEffects->GetNextItem(i, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
+      }
    }
 
    for (size_t i = 0, cnt = items.size(); i < cnt; i++)
@@ -941,11 +943,13 @@ void PluginRegistrationDialog::OnDisable(wxCommandEvent & WXUNUSED(evt))
 {
    std::vector<long> items;
 
-   long i = mEffects->GetNextItem(-1, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
-   while (i != wxNOT_FOUND)
    {
-      items.insert(items.begin(), i);
-      i = mEffects->GetNextItem(i, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
+      long i = mEffects->GetNextItem(-1, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
+      while (i != wxNOT_FOUND)
+      {
+         items.insert(items.begin(), i);
+         i = mEffects->GetNextItem(i, wxLIST_NEXT_ALL, wxLIST_STATE_SELECTED);
+      }
    }
 
    for (size_t i = 0, cnt = items.size(); i < cnt; i++)
@@ -1004,15 +1008,15 @@ void PluginRegistrationDialog::OnOK(wxCommandEvent & WXUNUSED(evt))
             wxString errMsgs;
 
             // Try to register the plugin via each provider until one succeeds
-            for (size_t j = 0, cnt = item.plugs.size(); j < cnt; j++)
+            for (size_t j = 0, cntj = item.plugs.size(); j < cntj; j++)
             {
                wxString errMsg;
                if (mm.RegisterEffectPlugin(item.plugs[j]->GetProviderID(), path,
                                      errMsg))
                {
-                  for (size_t j = 0, cnt = item.plugs.size(); j < cnt; j++)
+                  for (size_t k = 0, cntk = item.plugs.size(); k < cntk; k++)
                   {
-                     pm.mPlugins.erase(item.plugs[j]->GetProviderID() + wxT("_") + path);
+                     pm.mPlugins.erase(item.plugs[k]->GetProviderID() + wxT("_") + path);
                   }
                   // Bug 1893.  We've found a provider that works.
                   // Error messages from any that failed are no longer useful.
@@ -2410,13 +2414,13 @@ void PluginManager::CheckForUpdates(bool bFast)
                if (pathIndex.Index(path) == wxNOT_FOUND)
                {
                   PluginID ID = plugID + wxT("_") + path;
-                  PluginDescriptor & plug = mPlugins[ID];  // This will create a NEW descriptor
-                  plug.SetPluginType(PluginTypeStub);
-                  plug.SetID(ID);
-                  plug.SetProviderID(plugID);
-                  plug.SetPath(path);
-                  plug.SetEnabled(false);
-                  plug.SetValid(false);
+                  PluginDescriptor & plug2 = mPlugins[ID];  // This will create a NEW descriptor
+                  plug2.SetPluginType(PluginTypeStub);
+                  plug2.SetID(ID);
+                  plug2.SetProviderID(plugID);
+                  plug2.SetPath(path);
+                  plug2.SetEnabled(false);
+                  plug2.SetValid(false);
                }
             }
          }
diff --git a/src/TrackArtist.cpp b/src/TrackArtist.cpp
index a7f17a65c..7e3d7a952 100644
--- a/src/TrackArtist.cpp
+++ b/src/TrackArtist.cpp
@@ -1520,29 +1520,29 @@ void TrackArtist::DrawWaveform(TrackPanelDrawingContext &context,
    auto target2 = dynamic_cast<CutlineHandle*>(context.target.get());
 #endif
    for (const auto loc : track->GetCachedLocations()) {
-      bool highlight = false;
+      bool highlightLoc = false;
 #ifdef EXPERIMENTAL_TRACK_PANEL_HIGHLIGHTING
-      highlight =
+      highlightLoc =
          target2 && target2->GetTrack().get() == track &&
          target2->GetLocation() == loc;
 #endif
       const int xx = zoomInfo.TimeToPosition(loc.pos);
       if (xx >= 0 && xx < rect.width) {
-         dc.SetPen( highlight ? AColor::uglyPen : *wxGREY_PEN );
+         dc.SetPen( highlightLoc ? AColor::uglyPen : *wxGREY_PEN );
          AColor::Line(dc, (int) (rect.x + xx - 1), rect.y, (int) (rect.x + xx - 1), rect.y + rect.height);
          if (loc.typ == WaveTrackLocation::locationCutLine) {
-            dc.SetPen( highlight ? AColor::uglyPen : *wxRED_PEN );
+            dc.SetPen( highlightLoc ? AColor::uglyPen : *wxRED_PEN );
          }
          else {
 #ifdef EXPERIMENTAL_DA
             // JKC Black does not show up enough.
-            dc.SetPen(highlight ? AColor::uglyPen : *wxWHITE_PEN);
+            dc.SetPen(highlightLoc ? AColor::uglyPen : *wxWHITE_PEN);
 #else
-            dc.SetPen(highlight ? AColor::uglyPen : *wxBLACK_PEN);
+            dc.SetPen(highlightLoc ? AColor::uglyPen : *wxBLACK_PEN);
 #endif
          }
          AColor::Line(dc, (int) (rect.x + xx), rect.y, (int) (rect.x + xx), rect.y + rect.height);
-         dc.SetPen( highlight ? AColor::uglyPen : *wxGREY_PEN );
+         dc.SetPen( highlightLoc ? AColor::uglyPen : *wxGREY_PEN );
          AColor::Line(dc, (int) (rect.x + xx + 1), rect.y, (int) (rect.x + xx + 1), rect.y + rect.height);
       }
    }
@@ -1841,19 +1841,19 @@ void TrackArtist::DrawClipWaveform(TrackPanelDrawingContext &context,
    // the envelope and using a colored pen for the selected
    // part of the waveform
    {
-      double t0, t1;
+      double tt0, tt1;
       if (track->GetSelected() || track->IsSyncLockSelected()) {
-         t0 = track->LongSamplesToTime(track->TimeToLongSamples(selectedRegion.t0())),
-            t1 = track->LongSamplesToTime(track->TimeToLongSamples(selectedRegion.t1()));
+         tt0 = track->LongSamplesToTime(track->TimeToLongSamples(selectedRegion.t0())),
+            tt1 = track->LongSamplesToTime(track->TimeToLongSamples(selectedRegion.t1()));
       }
       else
-         t0 = t1 = 0.0;
+         tt0 = tt1 = 0.0;
       DrawWaveformBackground(dc, leftOffset, mid,
          env,
          zoomMin, zoomMax,
          track->ZeroLevelYCoordinate(mid),
          dB, dBRange,
-         t0, t1, zoomInfo, drawEnvelope,
+         tt0, tt1, zoomInfo, drawEnvelope,
          !track->GetSelected(), highlightEnvelope);
    }
 
diff --git a/src/effects/Effect.cpp b/src/effects/Effect.cpp
index 0259094f1..13fc71777 100644
--- a/src/effects/Effect.cpp
+++ b/src/effects/Effect.cpp
@@ -1705,9 +1705,11 @@ bool Effect::ProcessTrack(int count,
       // Get the current number of delayed samples and accumulate
       if (isProcessor)
       {
-         auto delay = GetLatency();
-         curDelay += delay;
-         delayRemaining += delay;
+         {
+            auto delay = GetLatency();
+            curDelay += delay;
+            delayRemaining += delay;
+         }
 
          // If the plugin has delayed the output by more samples than our current
          // block size, then we leave the output pointers alone.  This effectively
diff --git a/src/effects/Reverse.cpp b/src/effects/Reverse.cpp
index 6674c0372..4f487afef 100644
--- a/src/effects/Reverse.cpp
+++ b/src/effects/Reverse.cpp
@@ -193,8 +193,10 @@ bool EffectReverse::ProcessOneWave(int count, WaveTrack * track, sampleCount sta
    // the last clip of revClips is appended to the track first
    // PRL:  I don't think that matters, the sequence of storage of clips in the track
    // is not elsewhere assumed to be by time
-   for (auto it = revClips.rbegin(), end = revClips.rend(); it != end; ++it)
-      track->AddClip(std::move(*it));
+   {
+      for (auto it = revClips.rbegin(), end = revClips.rend(); it != end; ++it)
+         track->AddClip(std::move(*it));
+   }
 
    for (auto &clip : otherClips)
       track->AddClip(std::move(clip));
diff --git a/src/effects/ScienFilter.cpp b/src/effects/ScienFilter.cpp
index c2d5e0e2b..c3a462cf6 100644
--- a/src/effects/ScienFilter.cpp
+++ b/src/effects/ScienFilter.cpp
@@ -337,9 +337,11 @@ bool EffectScienFilter::Init()
    double rate = 0.0;
 
    auto trackRange = inputTracks()->Selected< const WaveTrack >();
-   auto t = *trackRange.begin();
 
-   mNyquist = (t ? t->GetRate() : GetActiveProject()->GetRate()) / 2.0;
+   {
+      auto t = *trackRange.begin();
+      mNyquist = (t ? t->GetRate() : GetActiveProject()->GetRate()) / 2.0;
+   }
 
    for (auto t : trackRange)
    {
@@ -662,8 +664,8 @@ bool EffectScienFilter::CalcFilter()
             fDCPoleDistSqr = fZPoleX + 1;    // dist from Nyquist
          for (int iPair = 1; iPair <= mOrder/2; iPair++)
          {
-            float fSPoleX = fC * cos (PI - iPair * PI / mOrder);
-            float fSPoleY = fC * sin (PI - iPair * PI / mOrder);
+            fSPoleX = fC * cos (PI - iPair * PI / mOrder);
+            fSPoleY = fC * sin (PI - iPair * PI / mOrder);
             BilinTransform (fSPoleX, fSPoleY, &fZPoleX, &fZPoleY);
             mpBiquad[iPair].fNumerCoeffs [0] = 1;
             if (mFilterSubtype == kLowPass)		// LOWPASS
diff --git a/src/effects/ladspa/LadspaEffect.cpp b/src/effects/ladspa/LadspaEffect.cpp
index 2c7b3662c..934fe35db 100644
--- a/src/effects/ladspa/LadspaEffect.cpp
+++ b/src/effects/ladspa/LadspaEffect.cpp
@@ -1090,9 +1090,9 @@ bool LadspaEffect::SetAutomationParameters(CommandParameters & parms)
 {
    for (unsigned long p = 0; p < mData->PortCount; p++)
    {
-      LADSPA_PortDescriptor d = mData->PortDescriptors[p];
+      LADSPA_PortDescriptor descriptor = mData->PortDescriptors[p];
 
-      if (LADSPA_IS_PORT_CONTROL(d) && LADSPA_IS_PORT_INPUT(d))
+      if (LADSPA_IS_PORT_CONTROL(descriptor) && LADSPA_IS_PORT_INPUT(descriptor))
       {
          wxString labelText = LAT1CTOWX(mData->PortNames[p]);
          double d = 0.0;
diff --git a/src/effects/lv2/LV2Effect.cpp b/src/effects/lv2/LV2Effect.cpp
index 37aa7dd43..c2b5c9149 100644
--- a/src/effects/lv2/LV2Effect.cpp
+++ b/src/effects/lv2/LV2Effect.cpp
@@ -1572,7 +1572,7 @@ bool LV2Effect::BuildPlain()
 
          mGroups.Sort();
 
-         for (size_t i = 0, cnt = mGroups.GetCount(); i < cnt; i++)
+         for (size_t i = 0, groupCount = mGroups.GetCount(); i < groupCount; i++)
          {
             wxString label = mGroups[i];
             if (label.IsEmpty())
@@ -1585,7 +1585,7 @@ bool LV2Effect::BuildPlain()
             gridSizer->AddGrowableCol(3);
 
             const auto & params = mGroupMap[mGroups[i]];
-            for (size_t pi = 0, cnt = params.size(); pi < cnt; pi++)
+            for (size_t pi = 0, paramCount = params.size(); pi < paramCount; pi++)
             {
                int p = params[pi];
                LV2Port & ctrl = mControls[p];
diff --git a/src/effects/nyquist/Nyquist.cpp b/src/effects/nyquist/Nyquist.cpp
index de299b15f..4610cdacf 100644
--- a/src/effects/nyquist/Nyquist.cpp
+++ b/src/effects/nyquist/Nyquist.cpp
@@ -610,7 +610,7 @@ bool NyquistEffect::Process()
       return true;
 
    // Restore the reentry counter (to zero) when we exit.
-   auto cleanup = valueRestorer( mReentryCount);
+   auto countRestorer = valueRestorer( mReentryCount);
    mReentryCount++;
    RegisterFunctions();
 
diff --git a/src/effects/vamp/VampEffect.cpp b/src/effects/vamp/VampEffect.cpp
index e326594c3..68d657f47 100644
--- a/src/effects/vamp/VampEffect.cpp
+++ b/src/effects/vamp/VampEffect.cpp
@@ -146,7 +146,7 @@ unsigned VampEffect::GetAudioInCount()
 
 bool VampEffect::GetAutomationParameters(CommandParameters & parms)
 {
-   for (size_t p = 0, cnt = mParameters.size(); p < cnt; p++)
+   for (size_t p = 0, paramCount = mParameters.size(); p < paramCount; p++)
    {
       wxString key = wxString::FromUTF8(mParameters[p].identifier.c_str());
       float value = mPlugin->getParameter(mParameters[p].identifier);
@@ -169,7 +169,7 @@ bool VampEffect::GetAutomationParameters(CommandParameters & parms)
          std::vector<IdentInterfaceSymbol> choices;
          int val = 0;
 
-         for (size_t i = 0, cnt = mParameters[p].valueNames.size(); i < cnt; i++)
+         for (size_t i = 0, choiceCount = mParameters[p].valueNames.size(); i < choiceCount; i++)
          {
             wxString choice = wxString::FromUTF8(mParameters[p].valueNames[i].c_str());
             if (size_t(value - mParameters[p].minValue + 0.5) == i)
@@ -193,7 +193,7 @@ bool VampEffect::GetAutomationParameters(CommandParameters & parms)
 bool VampEffect::SetAutomationParameters(CommandParameters & parms)
 {
    // First pass verifies values
-   for (size_t p = 0, cnt = mParameters.size(); p < cnt; p++)
+   for (size_t p = 0, paramCount = mParameters.size(); p < paramCount; p++)
    {
       wxString key = wxString::FromUTF8(mParameters[p].identifier.c_str());
       float lower = mParameters[p].minValue;
@@ -216,7 +216,7 @@ bool VampEffect::SetAutomationParameters(CommandParameters & parms)
          std::vector<IdentInterfaceSymbol> choices;
          int val;
 
-         for (size_t i = 0, cnt = mParameters[p].valueNames.size(); i < cnt; i++)
+         for (size_t i = 0, choiceCount = mParameters[p].valueNames.size(); i < choiceCount; i++)
          {
             wxString choice = wxString::FromUTF8(mParameters[p].valueNames[i].c_str());
             choices.push_back(choice);
@@ -238,7 +238,7 @@ bool VampEffect::SetAutomationParameters(CommandParameters & parms)
    }
 
    // Second pass sets the variables
-   for (size_t p = 0, cnt = mParameters.size(); p < cnt; p++)
+   for (size_t p = 0, paramCount = mParameters.size(); p < paramCount; p++)
    {
       wxString key = wxString::FromUTF8(mParameters[p].identifier.c_str());
       float lower = mParameters[p].minValue;
@@ -262,7 +262,7 @@ bool VampEffect::SetAutomationParameters(CommandParameters & parms)
          std::vector<IdentInterfaceSymbol> choices;
          int val = 0;
 
-         for (size_t i = 0, cnt = mParameters[p].valueNames.size(); i < cnt; i++)
+         for (size_t i = 0, choiceCount = mParameters[p].valueNames.size(); i < choiceCount; i++)
          {
             wxString choice = wxString::FromUTF8(mParameters[p].valueNames[i].c_str());
             choices.push_back(choice);
diff --git a/src/export/Export.cpp b/src/export/Export.cpp
index bab2c949a..baa1409e0 100644
--- a/src/export/Export.cpp
+++ b/src/export/Export.cpp
@@ -598,19 +598,21 @@ bool Exporter::GetFilename()
          mFilterIndex = fd.GetFilterIndex();
       }
 
-      int c = 0;
-      int i = -1;
-      for (const auto &pPlugin : mPlugins)
       {
-         ++i;
-         for (int j = 0; j < pPlugin->GetFormatCount(); j++)
+         int c = 0;
+         int i = -1;
+         for (const auto &pPlugin : mPlugins)
          {
-            if (mFilterIndex == c)
+            ++i;
+            for (int j = 0; j < pPlugin->GetFormatCount(); j++)
             {
-               mFormat = i;
-               mSubFormat = j;
+               if (mFilterIndex == c)
+               {
+                  mFormat = i;
+                  mSubFormat = j;
+               }
+               c++;
             }
-            c++;
          }
       }
 
diff --git a/src/export/ExportFFmpeg.cpp b/src/export/ExportFFmpeg.cpp
index d1b1a0906..fbcfe6bd8 100644
--- a/src/export/ExportFFmpeg.cpp
+++ b/src/export/ExportFFmpeg.cpp
@@ -806,13 +806,13 @@ bool ExportFFmpeg::EncodeAudioFrame(int16_t *pFrame, size_t frameSize)
    }
 
    // Read raw audio samples out of the FIFO in nAudioFrameSizeOut byte-sized groups to encode.
-   while ((ret = av_fifo_size(mEncAudioFifo.get())) >= nAudioFrameSizeOut)
+   while ( av_fifo_size(mEncAudioFifo.get()) >= nAudioFrameSizeOut)
    {
       ret = av_fifo_generic_read(mEncAudioFifo.get(), mEncAudioFifoOutBuf.get(), nAudioFrameSizeOut, NULL);
 
       AVPacketEx pkt;
 
-      int ret= encode_audio(mEncAudioCodecCtx.get(),
+      ret= encode_audio(mEncAudioCodecCtx.get(),
          &pkt,                          // out
          mEncAudioFifoOutBuf.get(), // in
          default_frame_size);
diff --git a/src/export/ExportFFmpegDialogs.cpp b/src/export/ExportFFmpegDialogs.cpp
index 8e3e03b15..bb636f561 100644
--- a/src/export/ExportFFmpegDialogs.cpp
+++ b/src/export/ExportFFmpegDialogs.cpp
@@ -574,26 +574,28 @@ void FFmpegPresets::SavePreset(ExportFFmpegOptions *parent, wxString &name)
       if (action == wxNO) return;
    }
 
-   wxWindow *wnd;
-   wxListBox *lb;
-
-   wnd = dynamic_cast<wxWindow*>(parent)->FindWindowById(FEFormatID,parent);
-   lb = dynamic_cast<wxListBox*>(wnd);
-   if (lb->GetSelection() < 0)
    {
-      AudacityMessageBox(_("Please select format before saving a profile"));
-      return;
-   }
-   format = lb->GetStringSelection();
+      wxWindow *wnd;
+      wxListBox *lb;
 
-   wnd = dynamic_cast<wxWindow*>(parent)->FindWindowById(FECodecID,parent);
-   lb = dynamic_cast<wxListBox*>(wnd);
-   if (lb->GetSelection() < 0)
-   {
-      AudacityMessageBox(_("Please select codec before saving a profile"));
-      return;
+      wnd = dynamic_cast<wxWindow*>(parent)->FindWindowById(FEFormatID,parent);
+      lb = dynamic_cast<wxListBox*>(wnd);
+      if (lb->GetSelection() < 0)
+      {
+         AudacityMessageBox(_("Please select format before saving a profile"));
+         return;
+      }
+      format = lb->GetStringSelection();
+
+      wnd = dynamic_cast<wxWindow*>(parent)->FindWindowById(FECodecID,parent);
+      lb = dynamic_cast<wxListBox*>(wnd);
+      if (lb->GetSelection() < 0)
+      {
+         AudacityMessageBox(_("Please select codec before saving a profile"));
+         return;
+      }
+      codec = lb->GetStringSelection();
    }
-   codec = lb->GetStringSelection();
 
    preset = &mPresets[name];
    preset->mPresetName = name;
diff --git a/src/export/ExportMultiple.cpp b/src/export/ExportMultiple.cpp
index 0cf07f859..52b11786c 100644
--- a/src/export/ExportMultiple.cpp
+++ b/src/export/ExportMultiple.cpp
@@ -752,7 +752,6 @@ ProgressResult ExportMultiple::ExportMultipleByTrack(bool byName,
 {
    wxASSERT(mProject);
    bool tagsPrompt = mProject->GetShowId3Dialog();
-   Track *tr;
    int l = 0;     // track counter
    auto ok = ProgressResult::Success;
    wxArrayString otherNames;
diff --git a/src/export/ExportPCM.cpp b/src/export/ExportPCM.cpp
index 73503e2b7..6e5130d00 100644
--- a/src/export/ExportPCM.cpp
+++ b/src/export/ExportPCM.cpp
@@ -253,15 +253,15 @@ void ExportPCMOptions::OnHeaderChoice(wxCommandEvent & WXUNUSED(evt))
    int num = sf_num_encodings();
    for (i = 0; i < num; i++)
    {
-      int enc = sf_encoding_index_to_subtype(i);
-      int fmt = format | enc;
+      int encSubtype = sf_encoding_index_to_subtype(i);
+      int fmt = format | encSubtype;
       bool valid  = ValidatePair(fmt);
       if (valid)
       {
          const auto name = sf_encoding_index_name(i);
          mEncodingNames.Add(name);
          mEncodingChoice->Append(name);
-         mEncodingFormats.push_back(enc);
+         mEncodingFormats.push_back(encSubtype);
          for (j = 0; j < sfnum; j++)
          {
             int enc = sfs[j];
diff --git a/src/import/ImportFLAC.cpp b/src/import/ImportFLAC.cpp
index 739d56366..547bd97d1 100644
--- a/src/import/ImportFLAC.cpp
+++ b/src/import/ImportFLAC.cpp
@@ -454,10 +454,11 @@ ProgressResult FLACImportFileHandle::Import(TrackFactory *trackFactory,
 
    mChannels.resize(mNumChannels);
 
-   auto iter = mChannels.begin();
-   for (size_t c = 0; c < mNumChannels; ++iter, ++c)
-      *iter = trackFactory->NewWaveTrack(mFormat, mSampleRate);
-
+   {
+      auto iter = mChannels.begin();
+      for (size_t c = 0; c < mNumChannels; ++iter, ++c)
+         *iter = trackFactory->NewWaveTrack(mFormat, mSampleRate);
+   }
 
 //Start OD
    bool useOD = false;
diff --git a/src/import/ImportPCM.cpp b/src/import/ImportPCM.cpp
index 68de4ef90..9905d1460 100644
--- a/src/import/ImportPCM.cpp
+++ b/src/import/ImportPCM.cpp
@@ -366,9 +366,12 @@ ProgressResult PCMImportFileHandle::Import(TrackFactory *trackFactory,
 
    NewChannelGroup channels(mInfo.channels);
 
-   auto iter = channels.begin();
-   for (int c = 0; c < mInfo.channels; ++iter, ++c)
-      *iter = trackFactory->NewWaveTrack(mFormat, mInfo.samplerate);
+   {
+      // iter not used outside this scope.
+      auto iter = channels.begin();
+      for (int c = 0; c < mInfo.channels; ++iter, ++c)
+         *iter = trackFactory->NewWaveTrack(mFormat, mInfo.samplerate);
+   }
 
    auto fileTotalFrames =
       (sampleCount)mInfo.frames; // convert from sf_count_t
@@ -673,8 +676,8 @@ ProgressResult PCMImportFileHandle::Import(TrackFactory *trackFactory,
                   ustr = id3_field_getstring(&frame->fields[1]);
                   if (ustr) {
                      // Is this duplication really needed?
-                     MallocString<> str{ (char *)id3_ucs4_utf8duplicate(ustr) };
-                     n = UTF8CTOWX(str.get());
+                     MallocString<> convStr{ (char *)id3_ucs4_utf8duplicate(ustr) };
+                     n = UTF8CTOWX(convStr.get());
                   }
 
                   ustr = id3_field_getstring(&frame->fields[2]);
@@ -685,8 +688,8 @@ ProgressResult PCMImportFileHandle::Import(TrackFactory *trackFactory,
 
                if (ustr) {
                   // Is this duplication really needed?
-                  MallocString<> str{ (char *)id3_ucs4_utf8duplicate(ustr) };
-                  v = UTF8CTOWX(str.get());
+                  MallocString<> convStr{ (char *)id3_ucs4_utf8duplicate(ustr) };
+                  v = UTF8CTOWX(convStr.get());
                }
 
                if (!n.IsEmpty() && !v.IsEmpty()) {
diff --git a/src/import/ImportRaw.cpp b/src/import/ImportRaw.cpp
index 3c52a3c8d..08f82e5a1 100644
--- a/src/import/ImportRaw.cpp
+++ b/src/import/ImportRaw.cpp
@@ -112,8 +112,6 @@ void ImportRaw(wxWindow *parent, const wxString &fileName,
 
    {
       SF_INFO sndInfo;
-      int result;
-
       unsigned numChannels = 0;
 
       try {
@@ -171,15 +169,17 @@ void ImportRaw(wxWindow *parent, const wxString &fileName,
          throw FileException{ FileException::Cause::Open, fileName };
       }
 
-      result = sf_command(sndFile.get(), SFC_SET_RAW_START_OFFSET, &offset, sizeof(offset));
-      if (result != 0) {
-         char str[1000];
-         sf_error_str(sndFile.get(), str, 1000);
-         wxPrintf("%s\n", str);
 
-         throw FileException{ FileException::Cause::Read, fileName };
+      {
+         int result = sf_command(sndFile.get(), SFC_SET_RAW_START_OFFSET, &offset, sizeof(offset));
+         if (result != 0) {
+            char str[1000];
+            sf_error_str(sndFile.get(), str, 1000);
+            wxPrintf("%s\n", str);
+
+            throw FileException{ FileException::Cause::Read, fileName };
+         }
       }
-
       SFCall<sf_count_t>(sf_seek, sndFile.get(), 0, SEEK_SET);
 
       auto totalFrames =
@@ -204,10 +204,12 @@ void ImportRaw(wxWindow *parent, const wxString &fileName,
       auto &channels = results[0];
       channels.resize(numChannels);
 
-      auto iter = channels.begin();
-      for (decltype(numChannels) c = 0; c < numChannels; ++iter, ++c)
-         *iter = trackFactory->NewWaveTrack(format, rate);
-
+      {
+         // iter not used outside this scope.
+         auto iter = channels.begin();
+         for (decltype(numChannels) c = 0; c < numChannels; ++iter, ++c)
+            *iter = trackFactory->NewWaveTrack(format, rate);
+      }
       const auto firstChannel = channels.begin()->get();
       auto maxBlockSize = firstChannel->GetMaxBlockSize();
 
@@ -232,14 +234,14 @@ void ImportRaw(wxWindow *parent, const wxString &fileName,
          block =
             limitSampleBufferSize( maxBlockSize, totalFrames - framescompleted );
 
-         sf_count_t result;
+         sf_count_t sf_result;
          if (format == int16Sample)
-            result = SFCall<sf_count_t>(sf_readf_short, sndFile.get(), (short *)srcbuffer.ptr(), block);
+            sf_result = SFCall<sf_count_t>(sf_readf_short, sndFile.get(), (short *)srcbuffer.ptr(), block);
          else
-            result = SFCall<sf_count_t>(sf_readf_float, sndFile.get(), (float *)srcbuffer.ptr(), block);
+            sf_result = SFCall<sf_count_t>(sf_readf_float, sndFile.get(), (float *)srcbuffer.ptr(), block);
 
-         if (result >= 0) {
-            block = result;
+         if (sf_result >= 0) {
+            block = sf_result;
          }
          else {
             // This is not supposed to happen, sndfile.h says result is always
diff --git a/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp b/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp
index 7d0e224c4..f88b96b9f 100644
--- a/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp
+++ b/src/tracks/playabletrack/wavetrack/ui/WaveTrackControls.cpp
@@ -613,9 +613,9 @@ void WaveTrackMenuTable::InitMenu(Menu *pMenu, void *pUserData)
    if ( isMono )
    {
       mpData = static_cast<TrackControls::InitMenuData*>(pUserData);
-      WaveTrack *const pTrack = static_cast<WaveTrack*>(mpData->pTrack);
+      WaveTrack *const pTrack2 = static_cast<WaveTrack*>(mpData->pTrack);
 
-      auto next = * ++ tracks->Find(pTrack);
+      auto next = * ++ tracks->Find(pTrack2);
 
       if (isMono) {
          const bool canMakeStereo =
@@ -626,7 +626,7 @@ void WaveTrackMenuTable::InitMenu(Menu *pMenu, void *pUserData)
          pMenu->Enable(OnMergeStereoID, canMakeStereo && !unsafe);
 
          int itemId;
-         switch (pTrack->GetChannel()) {
+         switch (pTrack2->GetChannel()) {
             case Track::LeftChannel:
                itemId = OnChannelLeftID;
                break;
diff --git a/src/tracks/playabletrack/wavetrack/ui/WaveTrackVZoomHandle.cpp b/src/tracks/playabletrack/wavetrack/ui/WaveTrackVZoomHandle.cpp
index 1305d4c00..bd7c57709 100644
--- a/src/tracks/playabletrack/wavetrack/ui/WaveTrackVZoomHandle.cpp
+++ b/src/tracks/playabletrack/wavetrack/ui/WaveTrackVZoomHandle.cpp
@@ -78,11 +78,11 @@ void WaveTrackVZoomHandle::DoZoom
    if (zoomEnd < zoomStart)
       std::swap( zoomStart, zoomEnd );
 
-   float min, max, c, minBand = 0;
+   float min, max, minBand = 0;
    const double rate = pTrack->GetRate();
    const float halfrate = rate / 2;
    float maxFreq = 8000.0;
-   const SpectrogramSettings &settings = pTrack->GetSpectrogramSettings();
+   const SpectrogramSettings &specSettings = pTrack->GetSpectrogramSettings();
    NumberScale scale;
    const bool spectral = (pTrack->GetDisplay() == WaveTrack::Spectrum);
    const bool spectrumLinear = spectral &&
@@ -105,8 +105,8 @@ void WaveTrackVZoomHandle::DoZoom
 
    if (spectral) {
       pTrack->GetSpectrumBounds(&min, &max);
-      scale = (settings.GetScale(min, max));
-      const auto fftLength = settings.GetFFTLength();
+      scale = (specSettings.GetScale(min, max));
+      const auto fftLength = specSettings.GetFFTLength();
       const float binSize = rate / fftLength;
       maxFreq = gPrefs->Read(wxT("/Spectrum/MaxFreq"), 8000L);
       // JKC:  Following discussions of Bug 1208 I'm allowing zooming in
@@ -118,11 +118,11 @@ void WaveTrackVZoomHandle::DoZoom
    }
    else{
       pTrack->GetDisplayBounds(&min, &max);
-      const WaveformSettings &settings = pTrack->GetWaveformSettings();
-      const bool linear = settings.isLinear();
+      const WaveformSettings &waveSettings = pTrack->GetWaveformSettings();
+      const bool linear = waveSettings.isLinear();
       if( !linear ){
-         top = (LINEAR_TO_DB(2.0) + settings.dBRange) / settings.dBRange;
-         half = (LINEAR_TO_DB(0.5) + settings.dBRange) / settings.dBRange;
+         top = (LINEAR_TO_DB(2.0) + waveSettings.dBRange) / waveSettings.dBRange;
+         half = (LINEAR_TO_DB(0.5) + waveSettings.dBRange) / waveSettings.dBRange;
       }
    }
 
@@ -175,7 +175,7 @@ void WaveTrackVZoomHandle::DoZoom
 
          // Waveform view - allow zooming down to a range of ZOOMLIMIT
          if (max - min < ZOOMLIMIT) {     // if user attempts to go smaller...
-            c = (min + max) / 2;           // ...set centre of view to centre of dragged area and top/bottom to ZOOMLIMIT/2 above/below
+            float c = (min + max) / 2;    // ...set centre of view to centre of dragged area and top/bottom to ZOOMLIMIT/2 above/below
             min = c - ZOOMLIMIT / 2.0;
             max = c + ZOOMLIMIT / 2.0;
          }
diff --git a/src/tracks/ui/Scrubbing.cpp b/src/tracks/ui/Scrubbing.cpp
index 4332577bb..5e3c81edc 100644
--- a/src/tracks/ui/Scrubbing.cpp
+++ b/src/tracks/ui/Scrubbing.cpp
@@ -344,7 +344,7 @@ bool Scrubber::MaybeStartScrubbing(wxCoord xx)
          );
          if (time1 != time0) {
             if (busy) {
-               auto position = mScrubStartPosition;
+               position = mScrubStartPosition;
                ctb->StopPlaying();
                mScrubStartPosition = position;
             }