diff --git a/src/d_net.cpp b/src/d_net.cpp
index bf56895f6..b984799f6 100644
--- a/src/d_net.cpp
+++ b/src/d_net.cpp
@@ -2048,7 +2048,7 @@ void FDynamicBuffer::SetData (const BYTE *data, int len)
 		m_BufferLen = (len + 255) & ~255;
 		m_Data = (BYTE *)M_Realloc (m_Data, m_BufferLen);
 	}
-	if (data)
+	if (data != NULL)
 	{
 		m_Len = len;
 		memcpy (m_Data, data, len);
@@ -2056,7 +2056,6 @@ void FDynamicBuffer::SetData (const BYTE *data, int len)
 	else
 	{
 		m_Len = 0;
-		M_Free((void *)data);
 	}
 }
 
diff --git a/src/decallib.cpp b/src/decallib.cpp
index 79c961099..4da7ba92c 100644
--- a/src/decallib.cpp
+++ b/src/decallib.cpp
@@ -762,6 +762,7 @@ void FDecalLib::ParseSlider (FScanner &sc)
 		}
 		else if (sc.Compare ("DistX"))
 		{
+			sc.MustGetFloat ();	// must remain to avoid breaking definitions that accidentally used DistX
 			Printf ("DistX in slider decal %s is unsupported\n", sliderName.GetChars());
 		}
 		else if (sc.Compare ("DistY"))
diff --git a/src/info.cpp b/src/info.cpp
index 1da057fe2..e26ac3b8e 100644
--- a/src/info.cpp
+++ b/src/info.cpp
@@ -577,17 +577,17 @@ CCMD (summonfoe)
 
 TMap<FName, DamageTypeDefinition> GlobalDamageDefinitions;
 
-void DamageTypeDefinition::Apply(FName const &type) 
+void DamageTypeDefinition::Apply(FName type) 
 { 
 	GlobalDamageDefinitions[type] = *this; 
 }
 
-DamageTypeDefinition *DamageTypeDefinition::Get(FName const &type) 
+DamageTypeDefinition *DamageTypeDefinition::Get(FName type) 
 { 
 	return GlobalDamageDefinitions.CheckKey(type); 
 }
 
-bool DamageTypeDefinition::IgnoreArmor(FName const &type)
+bool DamageTypeDefinition::IgnoreArmor(FName type)
 { 
 	DamageTypeDefinition *dtd = Get(type);
 	if (dtd) return dtd->NoArmor;
@@ -609,7 +609,7 @@ bool DamageTypeDefinition::IgnoreArmor(FName const &type)
 //
 //==========================================================================
 
-int DamageTypeDefinition::ApplyMobjDamageFactor(int damage, FName const &type, DmgFactors const * const factors)
+int DamageTypeDefinition::ApplyMobjDamageFactor(int damage, FName type, DmgFactors const * const factors)
 {
 	if (factors)
 	{
diff --git a/src/info.h b/src/info.h
index 0a6326c9a..19f03670d 100644
--- a/src/info.h
+++ b/src/info.h
@@ -225,9 +225,9 @@ public:
 		NoArmor = false;
 	}
 
-	static DamageTypeDefinition *Get(FName const &type);
-	static bool IgnoreArmor(FName const &type);
-	static int ApplyMobjDamageFactor(int damage, FName const &type, DmgFactors const * const factors);
+	static DamageTypeDefinition *Get(FName type);
+	static bool IgnoreArmor(FName type);
+	static int ApplyMobjDamageFactor(int damage, FName type, DmgFactors const * const factors);
 };
 
 
diff --git a/src/tarray.h b/src/tarray.h
index 790692e45..d32a688df 100644
--- a/src/tarray.h
+++ b/src/tarray.h
@@ -416,10 +416,10 @@ typedef unsigned int hash_t;
 template<class KT> struct THashTraits
 {
 	// Returns the hash value for a key.
-	hash_t Hash(const KT &key) { return (hash_t)(intptr_t)key; }
+	hash_t Hash(const KT key) { return (hash_t)(intptr_t)key; }
 
 	// Compares two keys, returning zero if they are the same.
-	int Compare(const KT &left, const KT &right) { return left != right; }
+	int Compare(const KT left, const KT right) { return left != right; }
 };
 
 template<class VT> struct TValueTraits
@@ -547,12 +547,12 @@ public:
 	//
 	//=======================================================================
 
-	VT &operator[] (const KT &key)
+	VT &operator[] (const KT key)
 	{
 		return GetNode(key)->Pair.Value;
 	}
 
-	const VT &operator[] (const KT &key) const
+	const VT &operator[] (const KT key) const
 	{
 		return GetNode(key)->Pair.Value;
 	}
@@ -566,13 +566,13 @@ public:
 	//
 	//=======================================================================
 
-	VT *CheckKey (const KT &key)
+	VT *CheckKey (const KT key)
 	{
 		Node *n = FindKey(key);
 		return n != NULL ? &n->Pair.Value : NULL;
 	}
 
-	const VT *CheckKey (const KT &key) const
+	const VT *CheckKey (const KT key) const
 	{
 		const Node *n = FindKey(key);
 		return n != NULL ? &n->Pair.Value : NULL;
@@ -591,7 +591,7 @@ public:
 	//
 	//=======================================================================
 
-	VT &Insert(const KT &key, const VT &value)
+	VT &Insert(const KT key, const VT &value)
 	{
 		Node *n = FindKey(key);
 		if (n != NULL)
@@ -614,7 +614,7 @@ public:
 	//
 	//=======================================================================
 
-	void Remove(const KT &key)
+	void Remove(const KT key)
 	{
 		DelKey(key);
 	}
@@ -649,13 +649,13 @@ protected:
 	hash_t Size;		/* must be a power of 2 */
 	hash_t NumUsed;
 
-	const Node *MainPosition(const KT &k) const
+	const Node *MainPosition(const KT k) const
 	{
 		HashTraits Traits;
 		return &Nodes[Traits.Hash(k) & (Size - 1)];
 	}
 
-	Node *MainPosition(const KT &k)
+	Node *MainPosition(const KT k)
 	{
 		HashTraits Traits;
 		return &Nodes[Traits.Hash(k) & (Size - 1)];
@@ -736,7 +736,7 @@ protected:
 	**
 	** The Value field is left unconstructed.
 	*/
-	Node *NewKey(const KT &key)
+	Node *NewKey(const KT key)
 	{
 		Node *mp = MainPosition(key);
 		if (!mp->IsNil())
@@ -775,7 +775,7 @@ protected:
 		return mp;
 	}
 
-	void DelKey(const KT &key)
+	void DelKey(const KT key)
 	{
 		Node *mp = MainPosition(key), **mpp;
 		HashTraits Traits;
@@ -814,7 +814,7 @@ protected:
 		}
 	}
 
-	Node *FindKey(const KT &key)
+	Node *FindKey(const KT key)
 	{
 		HashTraits Traits;
 		Node *n = MainPosition(key);
@@ -825,7 +825,7 @@ protected:
 		return n == NULL || n->IsNil() ? NULL : n;
 	}
 
-	const Node *FindKey(const KT &key) const
+	const Node *FindKey(const KT key) const
 	{
 		HashTraits Traits;
 		const Node *n = MainPosition(key);
@@ -836,7 +836,7 @@ protected:
 		return n == NULL || n->IsNil() ? NULL : n;
 	}
 
-	Node *GetNode(const KT &key)
+	Node *GetNode(const KT key)
 	{
 		Node *n = FindKey(key);
 		if (n != NULL)