diff --git a/modules/juce_audio_basics/midi/juce_MidiMessage.cpp b/modules/juce_audio_basics/midi/juce_MidiMessage.cpp
index 28fe3ab0f7..035276c14a 100644
--- a/modules/juce_audio_basics/midi/juce_MidiMessage.cpp
+++ b/modules/juce_audio_basics/midi/juce_MidiMessage.cpp
@@ -949,7 +949,7 @@ String MidiMessage::getMidiNoteName (int note, bool useSharps, bool includeOctav
     return String::empty;
 }
 
-const double MidiMessage::getMidiNoteInHertz (int noteNumber, const double frequencyOfA) noexcept
+double MidiMessage::getMidiNoteInHertz (int noteNumber, const double frequencyOfA) noexcept
 {
     return frequencyOfA * pow (2.0, (noteNumber - 69) / 12.0);
 }
diff --git a/modules/juce_audio_basics/midi/juce_MidiMessage.h b/modules/juce_audio_basics/midi/juce_MidiMessage.h
index 7813f6fb1f..f39138bbbb 100644
--- a/modules/juce_audio_basics/midi/juce_MidiMessage.h
+++ b/modules/juce_audio_basics/midi/juce_MidiMessage.h
@@ -891,7 +891,7 @@ public:
         The frequencyOfA parameter is an optional frequency for 'A', normally 440-444Hz for concert pitch.
         @see getMidiNoteName
     */
-    static const double getMidiNoteInHertz (int noteNumber, const double frequencyOfA = 440.0) noexcept;
+    static double getMidiNoteInHertz (int noteNumber, const double frequencyOfA = 440.0) noexcept;
 
     /** Returns the standard name of a GM instrument.
 
diff --git a/modules/juce_audio_utils/gui/juce_AudioDeviceSelectorComponent.cpp b/modules/juce_audio_utils/gui/juce_AudioDeviceSelectorComponent.cpp
index 0958b34986..ffff9b1973 100644
--- a/modules/juce_audio_utils/gui/juce_AudioDeviceSelectorComponent.cpp
+++ b/modules/juce_audio_utils/gui/juce_AudioDeviceSelectorComponent.cpp
@@ -875,7 +875,7 @@ public:
 
                 String error (setup.manager->setAudioDeviceSetup (config, true));
 
-                if (! error.isEmpty())
+                if (error.isNotEmpty())
                 {
                     //xxx
                 }
diff --git a/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.cpp b/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.cpp
index 00b642cf36..15a433f2a1 100644
--- a/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.cpp
+++ b/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.cpp
@@ -455,7 +455,7 @@ void MidiKeyboardComponent::drawWhiteNote (int midiNoteNumber,
 
     const String text (getWhiteNoteText (midiNoteNumber));
 
-    if (! text.isEmpty())
+    if (text.isNotEmpty())
     {
         g.setColour (textColour);
         g.setFont (Font (jmin (12.0f, keyWidth * 0.9f)).withHorizontalScale (0.8f));
diff --git a/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.h b/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.h
index f01b2d6787..16014a41e4 100644
--- a/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.h
+++ b/modules/juce_audio_utils/gui/juce_MidiKeyboardComponent.h
@@ -134,7 +134,7 @@ public:
     void setOrientation (Orientation newOrientation);
 
     /** Returns the keyboard's current direction. */
-    const Orientation getOrientation() const noexcept               { return orientation; }
+    Orientation getOrientation() const noexcept                     { return orientation; }
 
     /** Sets the range of midi notes that the keyboard will be limited to.
 
diff --git a/modules/juce_core/text/juce_String.cpp b/modules/juce_core/text/juce_String.cpp
index 3f5470ae1e..9fd5e88d5f 100644
--- a/modules/juce_core/text/juce_String.cpp
+++ b/modules/juce_core/text/juce_String.cpp
@@ -524,7 +524,7 @@ size_t String::getByteOffsetOfEnd() const noexcept
     return (size_t) (((char*) text.findTerminatingNull().getAddress()) - (char*) text.getAddress());
 }
 
-const juce_wchar String::operator[] (int index) const noexcept
+juce_wchar String::operator[] (int index) const noexcept
 {
     jassert (index == 0 || (index > 0 && index <= (int) text.lengthUpTo ((size_t) index + 1)));
     return text [index];
@@ -2289,7 +2289,7 @@ public:
             expect (s5.containsWholeWordIgnoreCase (L"Word"));
             expect (s5.containsWholeWordIgnoreCase ("Word3"));
             expect (! s5.containsWholeWordIgnoreCase (L"Wordx"));
-            expect (!s5.containsWholeWordIgnoreCase ("xWord2"));
+            expect (! s5.containsWholeWordIgnoreCase ("xWord2"));
             expect (s5.containsNonWhitespaceChars());
             expect (s5.containsOnly ("ordw23 "));
             expect (! String (" \n\r\t").containsNonWhitespaceChars());
diff --git a/modules/juce_core/text/juce_String.h b/modules/juce_core/text/juce_String.h
index 05c97ddc75..578e7e536e 100644
--- a/modules/juce_core/text/juce_String.h
+++ b/modules/juce_core/text/juce_String.h
@@ -579,7 +579,7 @@ public:
         then to use that to iterate the string.
         @see getCharPointer
     */
-    const juce_wchar operator[] (int index) const noexcept;
+    juce_wchar operator[] (int index) const noexcept;
 
     /** Returns the final character of the string.
         If the string is empty this will return 0.