diff --git a/src/c_console.cpp b/src/c_console.cpp
index 8635e6096..e0ea7e3cd 100644
--- a/src/c_console.cpp
+++ b/src/c_console.cpp
@@ -1935,10 +1935,7 @@ struct TabData
 	{
 	}
 
-	TabData(const TabData &other)
-	: UseCount(other.UseCount), TabName(other.TabName)
-	{
-	}
+	TabData(const TabData &other) = default;
 };
 
 static TArray<TabData> TabCommands (TArray<TabData>::NoInit);
diff --git a/src/cycler.cpp b/src/cycler.cpp
index dab4bab50..1d0d28486 100644
--- a/src/cycler.cpp
+++ b/src/cycler.cpp
@@ -60,22 +60,6 @@ FSerializer &Serialize(FSerializer &arc, const char *key, FCycler &c, FCycler *d
 	return arc;
 }
 
-//==========================================================================
-//
-//
-//
-//==========================================================================
-
-FCycler::FCycler()
-{
-	m_cycle = 0.;
-	m_cycleType = CYCLE_Linear;
-	m_shouldCycle = false;
-	m_start = m_current = 0.;
-	m_end = 0.;
-	m_increment = true;
-}
-
 
 //==========================================================================
 //
diff --git a/src/cycler.h b/src/cycler.h
index 680a976f7..0b49e644d 100644
--- a/src/cycler.h
+++ b/src/cycler.h
@@ -20,7 +20,10 @@ class FCycler
 	friend FSerializer &Serialize(FSerializer &arc, const char *key, FCycler &c, FCycler *def);
 
 public:
-   FCycler();
+	FCycler() = default;
+	FCycler(const FCycler &other) = default;
+	FCycler &operator=(const FCycler &other) = default;
+	
    void Update(double diff);
    void SetParams(double start, double end, double cycle, bool update = false);
    void ShouldCycle(bool sc) { m_shouldCycle = sc; }
@@ -28,8 +31,7 @@ public:
    double GetVal() { return m_current; }
 
    inline operator double () const { return m_current; }
-   
-protected:
+
    double m_start, m_end, m_current;
    double m_time, m_cycle;
    bool m_increment, m_shouldCycle;
diff --git a/src/d_dehacked.cpp b/src/d_dehacked.cpp
index 90f9f0867..2b34852a0 100644
--- a/src/d_dehacked.cpp
+++ b/src/d_dehacked.cpp
@@ -1017,7 +1017,7 @@ static int PatchThing (int thingy)
 			}
 			else if (stricmp (Line1 + linelen - 6, " sound") == 0)
 			{
-				FSoundID snd;
+				FSoundID snd = 0;
 				
 				if (val == 0 || val >= SoundMap.Size())
 				{
diff --git a/src/g_shared/a_dynlight.cpp b/src/g_shared/a_dynlight.cpp
index 1336e4533..4590310e0 100644
--- a/src/g_shared/a_dynlight.cpp
+++ b/src/g_shared/a_dynlight.cpp
@@ -119,6 +119,7 @@ static FDynamicLight *GetLight()
 	}
 	else ret = (FDynamicLight*)DynLightArena.Alloc(sizeof(FDynamicLight));
 	memset(ret, 0, sizeof(*ret));
+	ret->m_cycler.m_increment = true;
 	ret->next = level.lights;
 	level.lights = ret;
 	if (ret->next) ret->next->prev = ret;
diff --git a/src/name.h b/src/name.h
index 8dbb63444..76324fe7c 100644
--- a/src/name.h
+++ b/src/name.h
@@ -52,7 +52,7 @@ public:
 	FName (const char *text, size_t textlen, bool noCreate) { Index = NameData.FindName (text, textlen, noCreate); }
 	FName (const FString &text);
 	FName (const FString &text, bool noCreate);
-	FName (const FName &other) { Index = other.Index; }
+	FName (const FName &other) = default;
 	FName (ENamedName index) { Index = index; }
  //   ~FName () {}	// Names can be added but never removed.
 
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 2377673b4..e11982c89 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -6011,7 +6011,7 @@ int DLevelScript::CallFunction(int argCount, int funcIndex, int32_t *args)
 		case ACSF_PlayActorSound:
 			// PlaySound(tid, "SoundName", channel, volume, looping, attenuation, local)
 			{
-				FSoundID sid;
+				FSoundID sid = 0;
 
 				if (funcIndex == ACSF_PlaySound)
 				{
diff --git a/src/p_conversation.h b/src/p_conversation.h
index ad1465841..d199922f5 100644
--- a/src/p_conversation.h
+++ b/src/p_conversation.h
@@ -29,7 +29,7 @@ struct FStrifeDialogueNode
 
 	PClassActor *SpeakerType = nullptr;
 	FString SpeakerName;
-	FSoundID SpeakerVoice;
+	FSoundID SpeakerVoice = 0;
 	FString Backdrop;
 	FString Dialogue;
 	FString Goodbye; // must init to null for binary scripts to work as intended
diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index b256241c3..754f9bcd3 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -3001,7 +3001,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_Pain)
 	if (self->player && self->player->morphTics == 0)
 	{
 		const char *pain_amount;
-		FSoundID sfx_id;
+		FSoundID sfx_id = 0;
 
 		if (self->health < 25)
 			pain_amount = "*pain25";
diff --git a/src/p_terrain.cpp b/src/p_terrain.cpp
index 118958cf4..feeac2172 100644
--- a/src/p_terrain.cpp
+++ b/src/p_terrain.cpp
@@ -268,9 +268,8 @@ void P_InitTerrainTypes ()
 
 static void MakeDefaultTerrain ()
 {
-	FTerrainDef def;
+	FTerrainDef def = {};
 
-	memset (&def, 0, sizeof(def));
 	def.Name = "Solid";
 	def.Splash = -1;
 	Terrains.Push (def);
diff --git a/src/sc_man.cpp b/src/sc_man.cpp
index f1f415ea4..396777ef8 100644
--- a/src/sc_man.cpp
+++ b/src/sc_man.cpp
@@ -1149,11 +1149,6 @@ int FScriptPosition::WarnCounter;
 bool FScriptPosition::StrictErrors;	// makes all OPTERROR messages real errors.
 bool FScriptPosition::errorout;		// call I_Error instead of printing the error itself.
 
-FScriptPosition::FScriptPosition(const FScriptPosition &other)
-{
-	FileName = other.FileName;
-	ScriptLine = other.ScriptLine;
-}
 
 FScriptPosition::FScriptPosition(FString fname, int line)
 {
@@ -1167,13 +1162,6 @@ FScriptPosition::FScriptPosition(FScanner &sc)
 	ScriptLine = sc.GetMessageLine();
 }
 
-FScriptPosition &FScriptPosition::operator=(const FScriptPosition &other)
-{
-	FileName = other.FileName;
-	ScriptLine = other.ScriptLine;
-	return *this;
-}
-
 FScriptPosition &FScriptPosition::operator=(FScanner &sc)
 {
 	FileName = sc.ScriptName;
diff --git a/src/sc_man.h b/src/sc_man.h
index 35122654a..029363b94 100644
--- a/src/sc_man.h
+++ b/src/sc_man.h
@@ -170,10 +170,10 @@ struct FScriptPosition
 		FileName = NAME_None;
 		ScriptLine=0;
 	}
-	FScriptPosition(const FScriptPosition &other);
+	FScriptPosition(const FScriptPosition &other) = default;
 	FScriptPosition(FString fname, int line);
 	FScriptPosition(FScanner &sc);
-	FScriptPosition &operator=(const FScriptPosition &other);
+	FScriptPosition &operator=(const FScriptPosition &other) = default;
 	FScriptPosition &operator=(FScanner &sc);
 	void Message(int severity, const char *message,...) const GCCPRINTF(3,4);
 	static void ResetErrorCounter()
diff --git a/src/sound/s_advsound.cpp b/src/sound/s_advsound.cpp
index e4cf6c7d4..72271491e 100644
--- a/src/sound/s_advsound.cpp
+++ b/src/sound/s_advsound.cpp
@@ -1956,13 +1956,12 @@ int S_FindSkinnedSound (AActor *actor, FSoundID refid)
 int S_FindSkinnedSoundEx (AActor *actor, const char *name, const char *extendedname)
 {
 	FString fullname;
-	FSoundID id;
 
 	// Look for "name-extendedname";
 	fullname = name;
 	fullname += '-';
 	fullname += extendedname;
-	id = fullname;
+	FSoundID id = fullname;
 
 	if (id == 0)
 	{ // Look for "name"
diff --git a/src/sound/s_sndseq.cpp b/src/sound/s_sndseq.cpp
index ee0798f6e..7f22dd738 100644
--- a/src/sound/s_sndseq.cpp
+++ b/src/sound/s_sndseq.cpp
@@ -317,7 +317,7 @@ void DSeqNode::Serialize(FSerializer &arc)
 	unsigned int i;
 	FName seqName = NAME_None;
 	int delayTics = 0;
-	FSoundID id;
+	FSoundID id = 0;
 	float volume;
 	float atten = ATTN_NORM;
 	int seqnum;
@@ -805,7 +805,7 @@ static void AddSequence (int curseq, FName seqname, FName slot, int stopsound, c
 }
 
 DSeqNode::DSeqNode (int sequence, int modenum)
-: m_ModeNum(modenum), m_SequenceChoices(0)
+: m_CurrentSoundID(0), m_ModeNum(modenum), m_SequenceChoices(0)
 {
 	ActivateSequence (sequence);
 	if (!SequenceListHead)
diff --git a/src/sound/s_sound.h b/src/sound/s_sound.h
index 389e08312..275b57f49 100644
--- a/src/sound/s_sound.h
+++ b/src/sound/s_sound.h
@@ -98,10 +98,8 @@ extern TArray<sfxinfo_t> S_sfx;
 class FSoundID
 {
 public:
-	FSoundID()
-	{
-		ID = 0;
-	}
+	FSoundID() = default;
+
 	FSoundID(int id)
 	{
 		ID = id;
diff --git a/src/textures/anim_switches.cpp b/src/textures/anim_switches.cpp
index ab53210fe..455e4ebbf 100644
--- a/src/textures/anim_switches.cpp
+++ b/src/textures/anim_switches.cpp
@@ -229,7 +229,7 @@ FSwitchDef *FTextureManager::ParseSwitchDef (FScanner &sc, bool ignoreBad)
 	FSwitchDef::frame thisframe;
 	FTextureID picnum;
 	bool bad;
-	FSoundID sound;
+	FSoundID sound = 0;
 
 	bad = false;