diff --git a/apps/essimporter/CMakeLists.txt b/apps/essimporter/CMakeLists.txt
index 217d3e7b50..d53b48cf96 100644
--- a/apps/essimporter/CMakeLists.txt
+++ b/apps/essimporter/CMakeLists.txt
@@ -17,7 +17,6 @@ set(ESSIMPORTER_FILES
     importscpt.cpp
     importproj.cpp
     importsplm.cpp
-    importercontext.cpp
     converter.cpp
     convertacdt.cpp
     convertnpcc.cpp
diff --git a/apps/essimporter/importercontext.cpp b/apps/essimporter/importercontext.cpp
deleted file mode 100644
index e69de29bb2..0000000000
diff --git a/apps/opencs/CMakeLists.txt b/apps/opencs/CMakeLists.txt
index c9ca7838be..35838970ff 100644
--- a/apps/opencs/CMakeLists.txt
+++ b/apps/opencs/CMakeLists.txt
@@ -23,14 +23,14 @@ opencs_units (model/world
 
 
 opencs_units (model/world
-    universalid record commands columnbase columnimp scriptcontext cell refidcollection
+    universalid commands columnbase columnimp scriptcontext refidcollection
     refiddata refidadapterimp ref collectionbase refcollection columns infocollection tablemimedata cellcoordinates cellselection resources resourcesmanager scope
-    pathgrid land nestedtablewrapper nestedcollection nestedcoladapterimp nestedinfocollection
+    pathgrid land nestedcollection nestedcoladapterimp nestedinfocollection
     idcompletionmanager metadata defaultgmsts infoselectwrapper commandmacro
     )
 
 opencs_hdrs (model/world
-    columnimp disabletag idcollection collection info subcellcollection
+    columnimp disabletag idcollection collection info subcellcollection cell nestedtablewrapper record
     )
 
 
@@ -52,7 +52,7 @@ opencs_hdrs (model/tools
 
 opencs_units (view/doc
     viewmanager view operations operation subview startup filedialog newgame
-    filewidget adjusterwidget loader globaldebugprofilemenu runlogsubview sizehint
+    filewidget adjusterwidget loader globaldebugprofilemenu runlogsubview
     )
 
 
@@ -61,7 +61,7 @@ opencs_units (view/doc
     )
 
 opencs_hdrs (view/doc
-    subviewfactoryimp
+    subviewfactoryimp sizehint
     )
 
 
@@ -92,12 +92,12 @@ opencs_units (view/render
     )
 
 opencs_units (view/render
-    lighting lightingday lightingnight lightingbright object cell terrainstorage tagbase
+    lighting lightingday lightingnight lightingbright object cell terrainstorage
     cellarrow cellmarker cellborder pathgrid
     )
 
 opencs_hdrs (view/render
-    mask
+    mask tagbase
     )
 
 
@@ -123,7 +123,11 @@ opencs_units (model/prefs
     )
 
 opencs_units (model/filter
-    unarynode narynode leafnode booleannode parser andnode ornode notnode textnode valuenode
+    unarynode narynode parser andnode ornode notnode textnode valuenode
+    )
+
+opencs_hdrs (model/filter
+    leafnode booleannode
     )
 
 opencs_units (view/filter
diff --git a/apps/opencs/model/filter/booleannode.cpp b/apps/opencs/model/filter/booleannode.cpp
deleted file mode 100644
index 7f93b0b3b5..0000000000
--- a/apps/opencs/model/filter/booleannode.cpp
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "booleannode.hpp"
-
-namespace CSMWorld
-{
-    class IdTableBase;
-}
-
-CSMFilter::BooleanNode::BooleanNode(bool value)
-    : mTrue(value)
-{
-}
-
-bool CSMFilter::BooleanNode::test(const CSMWorld::IdTableBase& table, int row, const std::map<int, int>& columns) const
-{
-    return mTrue;
-}
-
-std::string CSMFilter::BooleanNode::toString(bool numericColumns) const
-{
-    return mTrue ? "true" : "false";
-}
diff --git a/apps/opencs/model/filter/booleannode.hpp b/apps/opencs/model/filter/booleannode.hpp
index 275cbf4e55..add06caa70 100644
--- a/apps/opencs/model/filter/booleannode.hpp
+++ b/apps/opencs/model/filter/booleannode.hpp
@@ -18,13 +18,19 @@ namespace CSMFilter
         bool mTrue;
 
     public:
-        explicit BooleanNode(bool value);
+        explicit BooleanNode(bool value)
+            : mTrue(value)
+        {
+        }
 
-        bool test(const CSMWorld::IdTableBase& table, int row, const std::map<int, int>& columns) const override;
+        bool test(const CSMWorld::IdTableBase& table, int row, const std::map<int, int>& columns) const override
+        {
+            return mTrue;
+        }
         ///< \return Can the specified table row pass through to filter?
         /// \param columns column ID to column index mapping
 
-        std::string toString(bool numericColumns) const override;
+        std::string toString(bool numericColumns) const override { return mTrue ? "true" : "false"; }
         ///< Return a string that represents this node.
         ///
         /// \param numericColumns Use numeric IDs instead of string to represent columns.
diff --git a/apps/opencs/model/filter/leafnode.cpp b/apps/opencs/model/filter/leafnode.cpp
deleted file mode 100644
index fd37c6cb64..0000000000
--- a/apps/opencs/model/filter/leafnode.cpp
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "leafnode.hpp"
-
-std::vector<int> CSMFilter::LeafNode::getReferencedColumns() const
-{
-    return std::vector<int>();
-}
diff --git a/apps/opencs/model/filter/leafnode.hpp b/apps/opencs/model/filter/leafnode.hpp
index bf90da18b0..0109304801 100644
--- a/apps/opencs/model/filter/leafnode.hpp
+++ b/apps/opencs/model/filter/leafnode.hpp
@@ -10,7 +10,7 @@ namespace CSMFilter
     class LeafNode : public Node
     {
     public:
-        std::vector<int> getReferencedColumns() const override;
+        std::vector<int> getReferencedColumns() const override { return {}; }
         ///< Return a list of the IDs of the columns referenced by this node. The column mapping
         /// passed into test as columns must contain all columns listed here.
     };
diff --git a/apps/opencs/model/world/cell.cpp b/apps/opencs/model/world/cell.cpp
deleted file mode 100644
index edf3b0d40c..0000000000
--- a/apps/opencs/model/world/cell.cpp
+++ /dev/null
@@ -1,10 +0,0 @@
-#include "cell.hpp"
-
-#include <sstream>
-
-void CSMWorld::Cell::load(ESM::ESMReader& esm, bool& isDeleted)
-{
-    ESM::Cell::load(esm, isDeleted, false);
-
-    mId = ESM::RefId::stringRefId(ESM::Cell::mId.toString());
-}
diff --git a/apps/opencs/model/world/cell.hpp b/apps/opencs/model/world/cell.hpp
index 5d4aefbda2..7e656859a5 100644
--- a/apps/opencs/model/world/cell.hpp
+++ b/apps/opencs/model/world/cell.hpp
@@ -1,8 +1,6 @@
 #ifndef CSM_WOLRD_CELL_H
 #define CSM_WOLRD_CELL_H
 
-#include <string>
-
 #include <components/esm3/loadcell.hpp>
 
 namespace ESM
@@ -20,7 +18,12 @@ namespace CSMWorld
     {
         ESM::RefId mId;
 
-        void load(ESM::ESMReader& esm, bool& isDeleted);
+        void load(ESM::ESMReader& esm, bool& isDeleted)
+        {
+            ESM::Cell::load(esm, isDeleted, false);
+
+            mId = ESM::RefId::stringRefId(ESM::Cell::mId.toString());
+        }
     };
 }
 
diff --git a/apps/opencs/model/world/nestedtablewrapper.cpp b/apps/opencs/model/world/nestedtablewrapper.cpp
deleted file mode 100644
index 0060276201..0000000000
--- a/apps/opencs/model/world/nestedtablewrapper.cpp
+++ /dev/null
@@ -1,6 +0,0 @@
-#include "nestedtablewrapper.hpp"
-
-int CSMWorld::NestedTableWrapperBase::size() const
-{
-    return -5;
-}
diff --git a/apps/opencs/model/world/nestedtablewrapper.hpp b/apps/opencs/model/world/nestedtablewrapper.hpp
index 4756409c96..69a00bf9c7 100644
--- a/apps/opencs/model/world/nestedtablewrapper.hpp
+++ b/apps/opencs/model/world/nestedtablewrapper.hpp
@@ -7,7 +7,7 @@ namespace CSMWorld
     {
         virtual ~NestedTableWrapperBase() = default;
 
-        virtual int size() const;
+        virtual int size() const { return -5; }
 
         NestedTableWrapperBase() = default;
     };
diff --git a/apps/opencs/model/world/record.cpp b/apps/opencs/model/world/record.cpp
deleted file mode 100644
index ddd9050828..0000000000
--- a/apps/opencs/model/world/record.cpp
+++ /dev/null
@@ -1,16 +0,0 @@
-#include "record.hpp"
-
-bool CSMWorld::RecordBase::isDeleted() const
-{
-    return mState == State_Deleted || mState == State_Erased;
-}
-
-bool CSMWorld::RecordBase::isErased() const
-{
-    return mState == State_Erased;
-}
-
-bool CSMWorld::RecordBase::isModified() const
-{
-    return mState == State_Modified || mState == State_ModifiedOnly;
-}
\ No newline at end of file
diff --git a/apps/opencs/model/world/record.hpp b/apps/opencs/model/world/record.hpp
index 35e4c82a35..29ac589bea 100644
--- a/apps/opencs/model/world/record.hpp
+++ b/apps/opencs/model/world/record.hpp
@@ -33,11 +33,11 @@ namespace CSMWorld
         virtual void assign(const RecordBase& record) = 0;
         ///< Will throw an exception if the types don't match.
 
-        bool isDeleted() const;
+        bool isDeleted() const { return mState == State_Deleted || mState == State_Erased; }
 
-        bool isErased() const;
+        bool isErased() const { return mState == State_Erased; }
 
-        bool isModified() const;
+        bool isModified() const { return mState == State_Modified || mState == State_ModifiedOnly; }
     };
 
     template <typename ESXRecordT>
diff --git a/apps/opencs/view/doc/sizehint.cpp b/apps/opencs/view/doc/sizehint.cpp
deleted file mode 100644
index 8b907ead09..0000000000
--- a/apps/opencs/view/doc/sizehint.cpp
+++ /dev/null
@@ -1,16 +0,0 @@
-#include "sizehint.hpp"
-
-CSVDoc::SizeHintWidget::SizeHintWidget(QWidget* parent)
-    : QWidget(parent)
-{
-}
-
-QSize CSVDoc::SizeHintWidget::sizeHint() const
-{
-    return mSize;
-}
-
-void CSVDoc::SizeHintWidget::setSizeHint(const QSize& size)
-{
-    mSize = size;
-}
diff --git a/apps/opencs/view/doc/sizehint.hpp b/apps/opencs/view/doc/sizehint.hpp
index a0296a51ec..66ae962e0a 100644
--- a/apps/opencs/view/doc/sizehint.hpp
+++ b/apps/opencs/view/doc/sizehint.hpp
@@ -11,11 +11,15 @@ namespace CSVDoc
         QSize mSize;
 
     public:
-        SizeHintWidget(QWidget* parent = nullptr);
+        explicit SizeHintWidget(QWidget* parent = nullptr)
+            : QWidget(parent)
+        {
+        }
+
         ~SizeHintWidget() override = default;
 
-        QSize sizeHint() const override;
-        void setSizeHint(const QSize& size);
+        QSize sizeHint() const override { return mSize; }
+        void setSizeHint(const QSize& size) { mSize = size; }
     };
 }
 
diff --git a/apps/opencs/view/render/tagbase.cpp b/apps/opencs/view/render/tagbase.cpp
deleted file mode 100644
index b52a553c97..0000000000
--- a/apps/opencs/view/render/tagbase.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-#include "tagbase.hpp"
-
-#include <apps/opencs/view/render/mask.hpp>
-
-CSVRender::TagBase::TagBase(Mask mask)
-    : mMask(mask)
-{
-}
-
-CSVRender::Mask CSVRender::TagBase::getMask() const
-{
-    return mMask;
-}
-
-QString CSVRender::TagBase::getToolTip(bool hideBasics, const WorldspaceHitResult& /*hit*/) const
-{
-    return "";
-}
diff --git a/apps/opencs/view/render/tagbase.hpp b/apps/opencs/view/render/tagbase.hpp
index a93267b6f4..6e6ee5b9a9 100644
--- a/apps/opencs/view/render/tagbase.hpp
+++ b/apps/opencs/view/render/tagbase.hpp
@@ -16,11 +16,14 @@ namespace CSVRender
         Mask mMask;
 
     public:
-        TagBase(Mask mask);
+        explicit TagBase(Mask mask)
+            : mMask(mask)
+        {
+        }
 
-        Mask getMask() const;
+        Mask getMask() const { return mMask; }
 
-        virtual QString getToolTip(bool hideBasics, const WorldspaceHitResult& hit) const;
+        virtual QString getToolTip(bool hideBasics, const WorldspaceHitResult& hit) const { return {}; }
     };
 }
 
diff --git a/apps/openmw/mwscript/consoleextensions.cpp b/apps/openmw/mwscript/consoleextensions.cpp
deleted file mode 100644
index 08a13e43ac..0000000000
--- a/apps/openmw/mwscript/consoleextensions.cpp
+++ /dev/null
@@ -1,11 +0,0 @@
-#include "consoleextensions.hpp"
-
-#include <components/interpreter/interpreter.hpp>
-
-namespace MWScript
-{
-    namespace Console
-    {
-        void installOpcodes(Interpreter::Interpreter& interpreter) {}
-    }
-}
diff --git a/apps/openmw/mwscript/consoleextensions.hpp b/apps/openmw/mwscript/consoleextensions.hpp
index 828557271a..5586323719 100644
--- a/apps/openmw/mwscript/consoleextensions.hpp
+++ b/apps/openmw/mwscript/consoleextensions.hpp
@@ -16,7 +16,7 @@ namespace MWScript
     /// \brief Script functionality limited to the console
     namespace Console
     {
-        void installOpcodes(Interpreter::Interpreter& interpreter);
+        void installOpcodes(Interpreter::Interpreter& interpreter) {}
     }
 }
 
diff --git a/components/compiler/nullerrorhandler.cpp b/components/compiler/nullerrorhandler.cpp
deleted file mode 100644
index 96735366eb..0000000000
--- a/components/compiler/nullerrorhandler.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-#include "nullerrorhandler.hpp"
-
-void Compiler::NullErrorHandler::report(const std::string& message, const TokenLoc& loc, Type type) {}
-
-void Compiler::NullErrorHandler::report(const std::string& message, Type type) {}
diff --git a/components/compiler/nullerrorhandler.hpp b/components/compiler/nullerrorhandler.hpp
index 7f2e086699..5d70ddd31a 100644
--- a/components/compiler/nullerrorhandler.hpp
+++ b/components/compiler/nullerrorhandler.hpp
@@ -9,10 +9,10 @@ namespace Compiler
 
     class NullErrorHandler : public ErrorHandler
     {
-        void report(const std::string& message, const TokenLoc& loc, Type type) override;
+        void report(const std::string& message, const TokenLoc& loc, Type type) override {}
         ///< Report error to the user.
 
-        void report(const std::string& message, Type type) override;
+        void report(const std::string& message, Type type) override {}
         ///< Report a file related error
     };
 }
diff --git a/components/compiler/opcodes.cpp b/components/compiler/opcodes.cpp
deleted file mode 100644
index eb57e28fd4..0000000000
--- a/components/compiler/opcodes.cpp
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "opcodes.hpp"
-
-namespace Compiler::Control
-{
-    const char* controls[numberOfControls] = { "playercontrols", "playerfighting", "playerjumping", "playerlooking",
-        "playermagic", "playerviewswitch", "vanitymode" };
-}
diff --git a/components/compiler/opcodes.hpp b/components/compiler/opcodes.hpp
index 55f431f049..c0aab2f08c 100644
--- a/components/compiler/opcodes.hpp
+++ b/components/compiler/opcodes.hpp
@@ -115,7 +115,15 @@ namespace Compiler
     {
         const int numberOfControls = 7;
 
-        extern const char* controls[numberOfControls];
+        inline constexpr const char* controls[numberOfControls] = {
+            "playercontrols",
+            "playerfighting",
+            "playerjumping",
+            "playerlooking",
+            "playermagic",
+            "playerviewswitch",
+            "vanitymode",
+        };
 
         const int opcodeEnable = 0x200007e;
         const int opcodeDisable = 0x2000085;
diff --git a/components/esm/common.cpp b/components/esm/common.cpp
deleted file mode 100644
index cde084f039..0000000000
--- a/components/esm/common.cpp
+++ /dev/null
@@ -1,16 +0,0 @@
-#include <cstdint>
-#include <string>
-
-namespace ESM
-{
-    std::string printName(const std::uint32_t typeId)
-    {
-        unsigned char typeName[4];
-        typeName[0] = typeId & 0xff;
-        typeName[1] = (typeId >> 8) & 0xff;
-        typeName[2] = (typeId >> 16) & 0xff;
-        typeName[3] = (typeId >> 24) & 0xff;
-
-        return std::string((char*)typeName, 4);
-    }
-}
diff --git a/components/esm/common.hpp b/components/esm/common.hpp
index 7d149a865c..76b06dd58b 100644
--- a/components/esm/common.hpp
+++ b/components/esm/common.hpp
@@ -42,7 +42,16 @@ namespace ESM
         std::uint64_t size;
     };
 
-    std::string printName(const std::uint32_t typeId);
+    inline std::string printName(const std::uint32_t typeId)
+    {
+        unsigned char typeName[4];
+        typeName[0] = typeId & 0xff;
+        typeName[1] = (typeId >> 8) & 0xff;
+        typeName[2] = (typeId >> 16) & 0xff;
+        typeName[3] = (typeId >> 24) & 0xff;
+
+        return std::string(reinterpret_cast<char*>(typeName), 4);
+    }
 }
 
 #endif // COMPONENT_ESM_COMMON_H
diff --git a/components/esm3/containerstate.cpp b/components/esm3/containerstate.cpp
deleted file mode 100644
index 63d21e24bd..0000000000
--- a/components/esm3/containerstate.cpp
+++ /dev/null
@@ -1,20 +0,0 @@
-#include "containerstate.hpp"
-
-namespace ESM
-{
-
-    void ContainerState::load(ESMReader& esm)
-    {
-        ObjectState::load(esm);
-
-        mInventory.load(esm);
-    }
-
-    void ContainerState::save(ESMWriter& esm, bool inInventory) const
-    {
-        ObjectState::save(esm, inInventory);
-
-        mInventory.save(esm);
-    }
-
-}
diff --git a/components/esm3/containerstate.hpp b/components/esm3/containerstate.hpp
index 55a19ffc15..1da420beca 100644
--- a/components/esm3/containerstate.hpp
+++ b/components/esm3/containerstate.hpp
@@ -12,8 +12,19 @@ namespace ESM
     {
         InventoryState mInventory;
 
-        void load(ESMReader& esm) override;
-        void save(ESMWriter& esm, bool inInventory = false) const override;
+        void load(ESMReader& esm) override
+        {
+            ObjectState::load(esm);
+
+            mInventory.load(esm);
+        }
+
+        void save(ESMWriter& esm, bool inInventory = false) const override
+        {
+            ObjectState::save(esm, inInventory);
+
+            mInventory.save(esm);
+        }
 
         ContainerState& asContainerState() override { return *this; }
         const ContainerState& asContainerState() const override { return *this; }
diff --git a/components/files/constrainedfilestream.cpp b/components/files/constrainedfilestream.cpp
deleted file mode 100644
index a79a31a842..0000000000
--- a/components/files/constrainedfilestream.cpp
+++ /dev/null
@@ -1,12 +0,0 @@
-#include <filesystem>
-
-#include "constrainedfilestream.hpp"
-
-namespace Files
-{
-    IStreamPtr openConstrainedFileStream(const std::filesystem::path& filename, std::size_t start, std::size_t length)
-    {
-        return std::make_unique<ConstrainedFileStream>(
-            std::make_unique<ConstrainedFileStreamBuf>(filename, start, length));
-    }
-}
diff --git a/components/files/constrainedfilestream.hpp b/components/files/constrainedfilestream.hpp
index 941f0ee493..2c0290aadd 100644
--- a/components/files/constrainedfilestream.hpp
+++ b/components/files/constrainedfilestream.hpp
@@ -5,8 +5,8 @@
 #include "istreamptr.hpp"
 #include "streamwithbuffer.hpp"
 
+#include <filesystem>
 #include <limits>
-#include <string>
 
 namespace Files
 {
@@ -14,9 +14,12 @@ namespace Files
     /// A file stream constrained to a specific region in the file, specified by the 'start' and 'length' parameters.
     using ConstrainedFileStream = StreamWithBuffer<ConstrainedFileStreamBuf>;
 
-    IStreamPtr openConstrainedFileStream(const std::filesystem::path& filename, std::size_t start = 0,
-        std::size_t length = std::numeric_limits<std::size_t>::max());
-
+    inline IStreamPtr openConstrainedFileStream(const std::filesystem::path& filename, std::size_t start = 0,
+        std::size_t length = std::numeric_limits<std::size_t>::max())
+    {
+        return std::make_unique<ConstrainedFileStream>(
+            std::make_unique<ConstrainedFileStreamBuf>(filename, start, length));
+    }
 }
 
 #endif
diff --git a/components/lua_ui/alignment.cpp b/components/lua_ui/alignment.cpp
deleted file mode 100644
index 358c5ba14b..0000000000
--- a/components/lua_ui/alignment.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-#include "alignment.hpp"
-
-namespace LuaUi
-{
-    MyGUI::Align alignmentToMyGui(Alignment horizontal, Alignment vertical)
-    {
-        MyGUI::Align align(MyGUI::Align::Center);
-        if (horizontal == Alignment::Start)
-            align |= MyGUI::Align::Left;
-        if (horizontal == Alignment::End)
-            align |= MyGUI::Align::Right;
-        if (vertical == Alignment::Start)
-            align |= MyGUI::Align::Top;
-        if (vertical == Alignment::End)
-            align |= MyGUI::Align::Bottom;
-        return align;
-    }
-}
diff --git a/components/lua_ui/alignment.hpp b/components/lua_ui/alignment.hpp
index 8503ffba03..b53ca04abc 100644
--- a/components/lua_ui/alignment.hpp
+++ b/components/lua_ui/alignment.hpp
@@ -12,7 +12,19 @@ namespace LuaUi
         End = 2
     };
 
-    MyGUI::Align alignmentToMyGui(Alignment horizontal, Alignment vertical);
+    inline MyGUI::Align alignmentToMyGui(Alignment horizontal, Alignment vertical)
+    {
+        MyGUI::Align align(MyGUI::Align::Center);
+        if (horizontal == Alignment::Start)
+            align |= MyGUI::Align::Left;
+        if (horizontal == Alignment::End)
+            align |= MyGUI::Align::Right;
+        if (vertical == Alignment::Start)
+            align |= MyGUI::Align::Top;
+        if (vertical == Alignment::End)
+            align |= MyGUI::Align::Bottom;
+        return align;
+    }
 }
 
-#endif // !OPENMW_LUAUI_PROPERTIES
+#endif