diff --git a/impeller/aiks/aiks_context.h b/impeller/aiks/aiks_context.h
index 326c99014227c..5ac0fcaa7bc03 100644
--- a/impeller/aiks/aiks_context.h
+++ b/impeller/aiks/aiks_context.h
@@ -15,7 +15,6 @@
 namespace impeller {
 
 struct Picture;
-class RenderPass;
 
 class AiksContext {
  public:
diff --git a/impeller/aiks/canvas.h b/impeller/aiks/canvas.h
index a302fc2622777..21e795743bc3d 100644
--- a/impeller/aiks/canvas.h
+++ b/impeller/aiks/canvas.h
@@ -15,6 +15,7 @@
 #include "impeller/aiks/paint.h"
 #include "impeller/aiks/picture.h"
 #include "impeller/core/sampler_descriptor.h"
+#include "impeller/entity/entity.h"
 #include "impeller/entity/entity_pass.h"
 #include "impeller/entity/geometry/geometry.h"
 #include "impeller/entity/geometry/vertices_geometry.h"
@@ -26,8 +27,6 @@
 
 namespace impeller {
 
-class Entity;
-
 struct CanvasStackEntry {
   Matrix transform;
   // |cull_rect| is conservative screen-space bounds of the clipped output area
diff --git a/impeller/aiks/paint_pass_delegate.h b/impeller/aiks/paint_pass_delegate.h
index 5efba41914277..c0154475ae0ef 100644
--- a/impeller/aiks/paint_pass_delegate.h
+++ b/impeller/aiks/paint_pass_delegate.h
@@ -12,8 +12,6 @@
 
 namespace impeller {
 
-class EntityPass;
-
 class PaintPassDelegate final : public EntityPassDelegate {
  public:
   explicit PaintPassDelegate(Paint paint);
diff --git a/impeller/core/allocator.h b/impeller/core/allocator.h
index 5c4c02b78f17d..07c1c93bf69ea 100644
--- a/impeller/core/allocator.h
+++ b/impeller/core/allocator.h
@@ -14,7 +14,6 @@ namespace impeller {
 
 class Context;
 class DeviceBuffer;
-class Texture;
 
 //------------------------------------------------------------------------------
 /// @brief      An object that allocates device memory.
diff --git a/impeller/core/sampler.h b/impeller/core/sampler.h
index 5792aaacbc0ff..afc3968c4cc23 100644
--- a/impeller/core/sampler.h
+++ b/impeller/core/sampler.h
@@ -4,6 +4,9 @@
 
 #pragma once
 
+#include <unordered_map>
+
+#include "impeller/base/comparable.h"
 #include "impeller/core/sampler_descriptor.h"
 
 namespace impeller {
@@ -27,4 +30,9 @@ class Sampler {
   Sampler& operator=(const Sampler&) = delete;
 };
 
+using SamplerMap = std::unordered_map<SamplerDescriptor,
+                                      std::shared_ptr<const Sampler>,
+                                      ComparableHash<SamplerDescriptor>,
+                                      ComparableEqual<SamplerDescriptor>>;
+
 }  // namespace impeller
diff --git a/impeller/core/sampler_descriptor.h b/impeller/core/sampler_descriptor.h
index 197e373f9aa02..45163b1cc2bdc 100644
--- a/impeller/core/sampler_descriptor.h
+++ b/impeller/core/sampler_descriptor.h
@@ -4,14 +4,11 @@
 
 #pragma once
 
-#include <unordered_map>
-
 #include "impeller/base/comparable.h"
 #include "impeller/core/formats.h"
 
 namespace impeller {
 
-class Sampler;
 class Context;
 
 struct SamplerDescriptor final : public Comparable<SamplerDescriptor> {
@@ -49,9 +46,4 @@ struct SamplerDescriptor final : public Comparable<SamplerDescriptor> {
   }
 };
 
-using SamplerMap = std::unordered_map<SamplerDescriptor,
-                                      std::shared_ptr<const Sampler>,
-                                      ComparableHash<SamplerDescriptor>,
-                                      ComparableEqual<SamplerDescriptor>>;
-
 }  // namespace impeller
diff --git a/impeller/renderer/context.h b/impeller/renderer/context.h
index b23055ef20e2e..9a24e435af1e3 100644
--- a/impeller/renderer/context.h
+++ b/impeller/renderer/context.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "flutter/fml/macros.h"
+#include "impeller/core/allocator.h"
 #include "impeller/core/capture.h"
 #include "impeller/core/formats.h"
 #include "impeller/core/host_buffer.h"
@@ -20,7 +21,6 @@ class ShaderLibrary;
 class SamplerLibrary;
 class CommandBuffer;
 class PipelineLibrary;
-class Allocator;
 
 //------------------------------------------------------------------------------
 /// @brief      To do anything rendering related with Impeller, you need a
diff --git a/impeller/renderer/sampler_library.h b/impeller/renderer/sampler_library.h
index 23039fd76b65b..f022488ce138a 100644
--- a/impeller/renderer/sampler_library.h
+++ b/impeller/renderer/sampler_library.h
@@ -4,9 +4,7 @@
 
 #pragma once
 
-#include <unordered_map>
-
-#include "flutter/fml/macros.h"
+#include "impeller/core/sampler.h"
 #include "impeller/core/sampler_descriptor.h"
 
 namespace impeller {