diff --git a/src/tint/transform/add_empty_entry_point.cc b/src/tint/transform/add_empty_entry_point.cc
index 5e33ce8bc1..0710d2bba6 100644
--- a/src/tint/transform/add_empty_entry_point.cc
+++ b/src/tint/transform/add_empty_entry_point.cc
@@ -20,8 +20,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::AddEmptyEntryPoint);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 AddEmptyEntryPoint::AddEmptyEntryPoint() = default;
 
@@ -47,5 +46,4 @@ void AddEmptyEntryPoint::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/add_empty_entry_point.h b/src/tint/transform/add_empty_entry_point.h
index 33c3a26fef..eb9dccd5a9 100644
--- a/src/tint/transform/add_empty_entry_point.h
+++ b/src/tint/transform/add_empty_entry_point.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Add an empty entry point to the module, if no other entry points exist.
 class AddEmptyEntryPoint final
@@ -47,7 +46,6 @@ class AddEmptyEntryPoint final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_ADD_EMPTY_ENTRY_POINT_H_
diff --git a/src/tint/transform/add_empty_entry_point_test.cc b/src/tint/transform/add_empty_entry_point_test.cc
index e8c1c72cc5..0854251e03 100644
--- a/src/tint/transform/add_empty_entry_point_test.cc
+++ b/src/tint/transform/add_empty_entry_point_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using AddEmptyEntryPointTest = TransformTest;
@@ -84,5 +83,4 @@ var<private> unused_entry_point : f32;
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/add_spirv_block_attribute.cc b/src/tint/transform/add_spirv_block_attribute.cc
index ffd389690a..91ab991d7b 100644
--- a/src/tint/transform/add_spirv_block_attribute.cc
+++ b/src/tint/transform/add_spirv_block_attribute.cc
@@ -26,8 +26,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::transform::AddSpirvBlockAttribute);
 TINT_INSTANTIATE_TYPEINFO(
     tint::transform::AddSpirvBlockAttribute::SpirvBlockAttribute);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 AddSpirvBlockAttribute::AddSpirvBlockAttribute() = default;
 
@@ -118,5 +117,4 @@ AddSpirvBlockAttribute::SpirvBlockAttribute::Clone(CloneContext* ctx) const {
       .Create<AddSpirvBlockAttribute::SpirvBlockAttribute>(ctx->dst->ID());
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/add_spirv_block_attribute.h b/src/tint/transform/add_spirv_block_attribute.h
index 5e68dad774..386a34118a 100644
--- a/src/tint/transform/add_spirv_block_attribute.h
+++ b/src/tint/transform/add_spirv_block_attribute.h
@@ -20,8 +20,7 @@
 #include "src/tint/ast/internal_attribute.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// AddSpirvBlockAttribute is a transform that adds an
 /// `@internal(spirv_block)` attribute to any structure that is used as the
@@ -70,7 +69,6 @@ class AddSpirvBlockAttribute final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_ADD_SPIRV_BLOCK_ATTRIBUTE_H_
diff --git a/src/tint/transform/add_spirv_block_attribute_test.cc b/src/tint/transform/add_spirv_block_attribute_test.cc
index 046b9c1630..b68920c25e 100644
--- a/src/tint/transform/add_spirv_block_attribute_test.cc
+++ b/src/tint/transform/add_spirv_block_attribute_test.cc
@@ -19,8 +19,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using AddSpirvBlockAttributeTest = TransformTest;
@@ -611,5 +610,4 @@ struct Inner {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/array_length_from_uniform.cc b/src/tint/transform/array_length_from_uniform.cc
index ff733ff01e..52c68f2c84 100644
--- a/src/tint/transform/array_length_from_uniform.cc
+++ b/src/tint/transform/array_length_from_uniform.cc
@@ -28,8 +28,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::transform::ArrayLengthFromUniform);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::ArrayLengthFromUniform::Config);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::ArrayLengthFromUniform::Result);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 ArrayLengthFromUniform::ArrayLengthFromUniform() = default;
 ArrayLengthFromUniform::~ArrayLengthFromUniform() = default;
@@ -229,5 +228,4 @@ ArrayLengthFromUniform::Result::Result(
 ArrayLengthFromUniform::Result::Result(const Result&) = default;
 ArrayLengthFromUniform::Result::~Result() = default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/array_length_from_uniform.h b/src/tint/transform/array_length_from_uniform.h
index 2505f17157..9d5cea60a2 100644
--- a/src/tint/transform/array_length_from_uniform.h
+++ b/src/tint/transform/array_length_from_uniform.h
@@ -21,12 +21,12 @@
 #include "src/tint/sem/binding_point.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 class CloneContext;
+}
 
-namespace transform {
+namespace tint::transform {
 
 /// ArrayLengthFromUniform is a transform that implements calls to arrayLength()
 /// by calculating the length from the total size of the storage buffer, which
@@ -119,7 +119,6 @@ class ArrayLengthFromUniform final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_ARRAY_LENGTH_FROM_UNIFORM_H_
diff --git a/src/tint/transform/array_length_from_uniform_test.cc b/src/tint/transform/array_length_from_uniform_test.cc
index 7cdcb5cdd2..42a334ce4e 100644
--- a/src/tint/transform/array_length_from_uniform_test.cc
+++ b/src/tint/transform/array_length_from_uniform_test.cc
@@ -20,8 +20,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using ArrayLengthFromUniformTest = TransformTest;
@@ -497,5 +496,4 @@ struct SB {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/binding_remapper.cc b/src/tint/transform/binding_remapper.cc
index 21155dfe57..3934b207d0 100644
--- a/src/tint/transform/binding_remapper.cc
+++ b/src/tint/transform/binding_remapper.cc
@@ -26,8 +26,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::BindingRemapper);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::BindingRemapper::Remappings);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 BindingRemapper::Remappings::Remappings(BindingPoints bp,
                                         AccessControls ac,
@@ -159,5 +158,4 @@ void BindingRemapper::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/binding_remapper.h b/src/tint/transform/binding_remapper.h
index f87f995e37..3e9f613470 100644
--- a/src/tint/transform/binding_remapper.h
+++ b/src/tint/transform/binding_remapper.h
@@ -21,8 +21,7 @@
 #include "src/tint/sem/binding_point.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// BindingPoint is an alias to sem::BindingPoint
 using BindingPoint = sem::BindingPoint;
@@ -86,7 +85,6 @@ class BindingRemapper final : public Castable<BindingRemapper, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_BINDING_REMAPPER_H_
diff --git a/src/tint/transform/binding_remapper_test.cc b/src/tint/transform/binding_remapper_test.cc
index 3fc0b19319..70c723216b 100644
--- a/src/tint/transform/binding_remapper_test.cc
+++ b/src/tint/transform/binding_remapper_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using BindingRemapperTest = TransformTest;
@@ -359,5 +358,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/builtin_polyfill.cc b/src/tint/transform/builtin_polyfill.cc
index 9cd2c678ef..c33d40fe5a 100644
--- a/src/tint/transform/builtin_polyfill.cc
+++ b/src/tint/transform/builtin_polyfill.cc
@@ -24,8 +24,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::BuiltinPolyfill);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::BuiltinPolyfill::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// The PIMPL state for the BuiltinPolyfill transform
 struct BuiltinPolyfill::State {
@@ -598,5 +597,4 @@ BuiltinPolyfill::Config::Config(const Builtins& b) : builtins(b) {}
 BuiltinPolyfill::Config::Config(const Config&) = default;
 BuiltinPolyfill::Config::~Config() = default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/builtin_polyfill.h b/src/tint/transform/builtin_polyfill.h
index dec716ef59..ada10158e2 100644
--- a/src/tint/transform/builtin_polyfill.h
+++ b/src/tint/transform/builtin_polyfill.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Implements builtins for backends that do not have a native implementation.
 class BuiltinPolyfill final : public Castable<BuiltinPolyfill, Transform> {
@@ -91,7 +90,6 @@ class BuiltinPolyfill final : public Castable<BuiltinPolyfill, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_BUILTIN_POLYFILL_H_
diff --git a/src/tint/transform/builtin_polyfill_test.cc b/src/tint/transform/builtin_polyfill_test.cc
index 49e0471259..c5cc2c5ff7 100644
--- a/src/tint/transform/builtin_polyfill_test.cc
+++ b/src/tint/transform/builtin_polyfill_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using Level = BuiltinPolyfill::Level;
@@ -1117,5 +1116,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/calculate_array_length.cc b/src/tint/transform/calculate_array_length.cc
index 05fcb0f2f1..589d21e8df 100644
--- a/src/tint/transform/calculate_array_length.cc
+++ b/src/tint/transform/calculate_array_length.cc
@@ -34,8 +34,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::transform::CalculateArrayLength);
 TINT_INSTANTIATE_TYPEINFO(
     tint::transform::CalculateArrayLength::BufferSizeIntrinsic);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 namespace {
 
@@ -239,5 +238,4 @@ void CalculateArrayLength::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/calculate_array_length.h b/src/tint/transform/calculate_array_length.h
index dfc1508ced..0ed7a5d42a 100644
--- a/src/tint/transform/calculate_array_length.h
+++ b/src/tint/transform/calculate_array_length.h
@@ -20,12 +20,12 @@
 #include "src/tint/ast/internal_attribute.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 class CloneContext;
+}
 
-namespace transform {
+namespace tint::transform {
 
 /// CalculateArrayLength is a transform used to replace calls to arrayLength()
 /// with a value calculated from the size of the storage buffer.
@@ -78,7 +78,6 @@ class CalculateArrayLength final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_CALCULATE_ARRAY_LENGTH_H_
diff --git a/src/tint/transform/calculate_array_length_test.cc b/src/tint/transform/calculate_array_length_test.cc
index 17d28fdf45..dec1698de0 100644
--- a/src/tint/transform/calculate_array_length_test.cc
+++ b/src/tint/transform/calculate_array_length_test.cc
@@ -18,8 +18,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using CalculateArrayLengthTest = TransformTest;
@@ -549,5 +548,4 @@ struct SB2 {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/canonicalize_entry_point_io.cc b/src/tint/transform/canonicalize_entry_point_io.cc
index 1eaa5dbe65..9d72887cdd 100644
--- a/src/tint/transform/canonicalize_entry_point_io.cc
+++ b/src/tint/transform/canonicalize_entry_point_io.cc
@@ -28,8 +28,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::CanonicalizeEntryPointIO);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::CanonicalizeEntryPointIO::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 CanonicalizeEntryPointIO::CanonicalizeEntryPointIO() = default;
 CanonicalizeEntryPointIO::~CanonicalizeEntryPointIO() = default;
@@ -775,5 +774,4 @@ CanonicalizeEntryPointIO::Config::Config(ShaderStyle style,
 CanonicalizeEntryPointIO::Config::Config(const Config&) = default;
 CanonicalizeEntryPointIO::Config::~Config() = default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/canonicalize_entry_point_io.h b/src/tint/transform/canonicalize_entry_point_io.h
index 48b7f40555..eab4128819 100644
--- a/src/tint/transform/canonicalize_entry_point_io.h
+++ b/src/tint/transform/canonicalize_entry_point_io.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// CanonicalizeEntryPointIO is a transform used to rewrite shader entry point
 /// interfaces into a form that the generators can handle. Each entry point
@@ -143,7 +142,6 @@ class CanonicalizeEntryPointIO final
   struct State;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_CANONICALIZE_ENTRY_POINT_IO_H_
diff --git a/src/tint/transform/canonicalize_entry_point_io_test.cc b/src/tint/transform/canonicalize_entry_point_io_test.cc
index 6147fe0613..bf4d699910 100644
--- a/src/tint/transform/canonicalize_entry_point_io_test.cc
+++ b/src/tint/transform/canonicalize_entry_point_io_test.cc
@@ -17,8 +17,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using CanonicalizeEntryPointIOTest = TransformTest;
@@ -4037,5 +4036,4 @@ fn main() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/combine_samplers.cc b/src/tint/transform/combine_samplers.cc
index ab0b90ded8..4b1e892a3e 100644
--- a/src/tint/transform/combine_samplers.cc
+++ b/src/tint/transform/combine_samplers.cc
@@ -36,8 +36,7 @@ bool IsGlobal(const tint::sem::VariablePair& pair) {
 
 }  // namespace
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 CombineSamplers::BindingInfo::BindingInfo(const BindingMap& map,
                                           const sem::BindingPoint& placeholder)
@@ -351,5 +350,4 @@ void CombineSamplers::Run(CloneContext& ctx,
   State(ctx, binding_info).Run();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/combine_samplers.h b/src/tint/transform/combine_samplers.h
index f55c275e9e..d15d2ab855 100644
--- a/src/tint/transform/combine_samplers.h
+++ b/src/tint/transform/combine_samplers.h
@@ -21,8 +21,7 @@
 #include "src/tint/sem/sampler_texture_pair.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// This transform converts all separate texture/sampler refences in a
 /// program into combined texture/samplers. This is required for GLSL,
@@ -104,7 +103,6 @@ class CombineSamplers final : public Castable<CombineSamplers, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_COMBINE_SAMPLERS_H_
diff --git a/src/tint/transform/combine_samplers_test.cc b/src/tint/transform/combine_samplers_test.cc
index f223cb1e54..cb60103a32 100644
--- a/src/tint/transform/combine_samplers_test.cc
+++ b/src/tint/transform/combine_samplers_test.cc
@@ -19,8 +19,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using CombineSamplersTest = TransformTest;
@@ -1008,5 +1007,4 @@ fn main() -> vec4<f32> {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/decompose_memory_access.cc b/src/tint/transform/decompose_memory_access.cc
index 50805518bc..699eeb4fbc 100644
--- a/src/tint/transform/decompose_memory_access.cc
+++ b/src/tint/transform/decompose_memory_access.cc
@@ -41,8 +41,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::DecomposeMemoryAccess);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::DecomposeMemoryAccess::Intrinsic);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 namespace {
 
@@ -991,8 +990,7 @@ void DecomposeMemoryAccess::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Offset);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::OffsetLiteral);
diff --git a/src/tint/transform/decompose_memory_access.h b/src/tint/transform/decompose_memory_access.h
index d1c2ce1390..efcd39b118 100644
--- a/src/tint/transform/decompose_memory_access.h
+++ b/src/tint/transform/decompose_memory_access.h
@@ -20,12 +20,12 @@
 #include "src/tint/ast/internal_attribute.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 class CloneContext;
+}
 
-namespace transform {
+namespace tint::transform {
 
 /// DecomposeMemoryAccess is a transform used to replace storage and uniform
 /// buffer accesses with a combination of load, store or atomic functions on
@@ -125,7 +125,6 @@ class DecomposeMemoryAccess final
   struct State;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_DECOMPOSE_MEMORY_ACCESS_H_
diff --git a/src/tint/transform/decompose_memory_access_test.cc b/src/tint/transform/decompose_memory_access_test.cc
index ec47d9a70f..dadb4226da 100644
--- a/src/tint/transform/decompose_memory_access_test.cc
+++ b/src/tint/transform/decompose_memory_access_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using DecomposeMemoryAccessTest = TransformTest;
@@ -2800,5 +2799,4 @@ struct S {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/decompose_strided_array.cc b/src/tint/transform/decompose_strided_array.cc
index 0265704cff..74b6903b36 100644
--- a/src/tint/transform/decompose_strided_array.cc
+++ b/src/tint/transform/decompose_strided_array.cc
@@ -29,8 +29,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::DecomposeStridedArray);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using DecomposedArrays = std::unordered_map<const sem::Array*, Symbol>;
@@ -158,5 +157,4 @@ void DecomposeStridedArray::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/decompose_strided_array.h b/src/tint/transform/decompose_strided_array.h
index ccf869190f..505f5cbecd 100644
--- a/src/tint/transform/decompose_strided_array.h
+++ b/src/tint/transform/decompose_strided_array.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// DecomposeStridedArray transforms replaces arrays with a non-default
 /// `@stride` attribute with an array of structure elements, where the
@@ -55,7 +54,6 @@ class DecomposeStridedArray final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_DECOMPOSE_STRIDED_ARRAY_H_
diff --git a/src/tint/transform/decompose_strided_array_test.cc b/src/tint/transform/decompose_strided_array_test.cc
index 63c7823720..98ef2c42a9 100644
--- a/src/tint/transform/decompose_strided_array_test.cc
+++ b/src/tint/transform/decompose_strided_array_test.cc
@@ -23,8 +23,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using DecomposeStridedArrayTest = TransformTest;
@@ -694,5 +693,4 @@ fn f() {
   EXPECT_EQ(expect, str(got));
 }
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/decompose_strided_matrix.cc b/src/tint/transform/decompose_strided_matrix.cc
index 6f06c80a36..fd7194d2f1 100644
--- a/src/tint/transform/decompose_strided_matrix.cc
+++ b/src/tint/transform/decompose_strided_matrix.cc
@@ -27,8 +27,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::DecomposeStridedMatrix);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 /// MatrixInfo describes a matrix member with a custom stride
@@ -247,5 +246,4 @@ void DecomposeStridedMatrix::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/decompose_strided_matrix.h b/src/tint/transform/decompose_strided_matrix.h
index 9a4c7b7694..bcde5aa5b7 100644
--- a/src/tint/transform/decompose_strided_matrix.h
+++ b/src/tint/transform/decompose_strided_matrix.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// DecomposeStridedMatrix transforms replaces matrix members of storage or
 /// uniform buffer structures, that have a stride attribute, into an array
@@ -55,7 +54,6 @@ class DecomposeStridedMatrix final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_DECOMPOSE_STRIDED_MATRIX_H_
diff --git a/src/tint/transform/decompose_strided_matrix_test.cc b/src/tint/transform/decompose_strided_matrix_test.cc
index 4fe08a01de..73389991d6 100644
--- a/src/tint/transform/decompose_strided_matrix_test.cc
+++ b/src/tint/transform/decompose_strided_matrix_test.cc
@@ -24,8 +24,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using DecomposeStridedMatrixTest = TransformTest;
@@ -667,5 +666,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/expand_compound_assignment.cc b/src/tint/transform/expand_compound_assignment.cc
index 3a986a2762..0473fae1f7 100644
--- a/src/tint/transform/expand_compound_assignment.cc
+++ b/src/tint/transform/expand_compound_assignment.cc
@@ -27,8 +27,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::ExpandCompoundAssignment);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 ExpandCompoundAssignment::ExpandCompoundAssignment() = default;
 
@@ -192,5 +191,4 @@ void ExpandCompoundAssignment::Run(CloneContext& ctx,
   state.Finalize();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/expand_compound_assignment.h b/src/tint/transform/expand_compound_assignment.h
index 644711770d..b461bed82e 100644
--- a/src/tint/transform/expand_compound_assignment.h
+++ b/src/tint/transform/expand_compound_assignment.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Converts compound assignment statements to regular assignment statements,
 /// hoisting the LHS expression if necessary.
@@ -65,7 +64,6 @@ class ExpandCompoundAssignment
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_EXPAND_COMPOUND_ASSIGNMENT_H_
diff --git a/src/tint/transform/expand_compound_assignment_test.cc b/src/tint/transform/expand_compound_assignment_test.cc
index dc0992fce8..d3fa510003 100644
--- a/src/tint/transform/expand_compound_assignment_test.cc
+++ b/src/tint/transform/expand_compound_assignment_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using ExpandCompoundAssignmentTest = TransformTest;
@@ -742,5 +741,4 @@ fn main() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/first_index_offset.cc b/src/tint/transform/first_index_offset.cc
index 0a21017555..46a2dcd245 100644
--- a/src/tint/transform/first_index_offset.cc
+++ b/src/tint/transform/first_index_offset.cc
@@ -28,8 +28,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::transform::FirstIndexOffset);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::FirstIndexOffset::BindingPoint);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::FirstIndexOffset::Data);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 // Uniform buffer member names
@@ -184,5 +183,4 @@ void FirstIndexOffset::Run(CloneContext& ctx,
                     instance_index_offset);
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/first_index_offset.h b/src/tint/transform/first_index_offset.h
index 21636f3e03..43d003d4ed 100644
--- a/src/tint/transform/first_index_offset.h
+++ b/src/tint/transform/first_index_offset.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Adds firstVertex/Instance (injected via root constants) to
 /// vertex/instance index builtins.
@@ -137,7 +136,6 @@ class FirstIndexOffset final : public Castable<FirstIndexOffset, Transform> {
   uint32_t group_ = 0;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_FIRST_INDEX_OFFSET_H_
diff --git a/src/tint/transform/first_index_offset_test.cc b/src/tint/transform/first_index_offset_test.cc
index 00822ff63b..ee914390ce 100644
--- a/src/tint/transform/first_index_offset_test.cc
+++ b/src/tint/transform/first_index_offset_test.cc
@@ -20,8 +20,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using FirstIndexOffsetTest = TransformTest;
@@ -646,5 +645,4 @@ fn func(i : u32) -> u32 {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/fold_constants.cc b/src/tint/transform/fold_constants.cc
index 08995eb2dd..b814c5cdc8 100644
--- a/src/tint/transform/fold_constants.cc
+++ b/src/tint/transform/fold_constants.cc
@@ -26,8 +26,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::FoldConstants);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 FoldConstants::FoldConstants() = default;
 
@@ -95,5 +94,4 @@ void FoldConstants::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/fold_constants.h b/src/tint/transform/fold_constants.h
index 7f964d1655..fbe7abd7b1 100644
--- a/src/tint/transform/fold_constants.h
+++ b/src/tint/transform/fold_constants.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// FoldConstants transforms the AST by folding constant expressions
 class FoldConstants final : public Castable<FoldConstants, Transform> {
@@ -41,7 +40,6 @@ class FoldConstants final : public Castable<FoldConstants, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_FOLD_CONSTANTS_H_
diff --git a/src/tint/transform/fold_constants_test.cc b/src/tint/transform/fold_constants_test.cc
index fd57c929f0..d8121bc256 100644
--- a/src/tint/transform/fold_constants_test.cc
+++ b/src/tint/transform/fold_constants_test.cc
@@ -20,8 +20,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using FoldConstantsTest = TransformTest;
@@ -423,5 +422,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/fold_trivial_single_use_lets.cc b/src/tint/transform/fold_trivial_single_use_lets.cc
index 33dc55da07..a0f02a8f00 100644
--- a/src/tint/transform/fold_trivial_single_use_lets.cc
+++ b/src/tint/transform/fold_trivial_single_use_lets.cc
@@ -23,8 +23,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::FoldTrivialSingleUseLets);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 const ast::VariableDeclStatement* AsTrivialLetDecl(const ast::Statement* stmt) {
@@ -88,5 +87,4 @@ void FoldTrivialSingleUseLets::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/fold_trivial_single_use_lets.h b/src/tint/transform/fold_trivial_single_use_lets.h
index 858f6da009..d343b76482 100644
--- a/src/tint/transform/fold_trivial_single_use_lets.h
+++ b/src/tint/transform/fold_trivial_single_use_lets.h
@@ -20,8 +20,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// FoldTrivialSingleUseLets is an optimizer for folding away trivial `let`
 /// statements into their single place of use. This transform is intended to
@@ -55,7 +54,6 @@ class FoldTrivialSingleUseLets final
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_FOLD_TRIVIAL_SINGLE_USE_LETS_H_
diff --git a/src/tint/transform/fold_trivial_single_use_lets_test.cc b/src/tint/transform/fold_trivial_single_use_lets_test.cc
index 09939e13d8..e08c19117f 100644
--- a/src/tint/transform/fold_trivial_single_use_lets_test.cc
+++ b/src/tint/transform/fold_trivial_single_use_lets_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using FoldTrivialSingleUseLetsTest = TransformTest;
@@ -184,5 +183,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/for_loop_to_loop.cc b/src/tint/transform/for_loop_to_loop.cc
index f7fda57edd..14d5edbfec 100644
--- a/src/tint/transform/for_loop_to_loop.cc
+++ b/src/tint/transform/for_loop_to_loop.cc
@@ -19,8 +19,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::ForLoopToLoop);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 ForLoopToLoop::ForLoopToLoop() = default;
 
 ForLoopToLoop::~ForLoopToLoop() = default;
@@ -72,5 +71,4 @@ void ForLoopToLoop::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/for_loop_to_loop.h b/src/tint/transform/for_loop_to_loop.h
index 94b046091c..54286d4c28 100644
--- a/src/tint/transform/for_loop_to_loop.h
+++ b/src/tint/transform/for_loop_to_loop.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// ForLoopToLoop is a Transform that converts a for-loop statement into a loop
 /// statement. This is required by the SPIR-V writer.
@@ -48,7 +47,6 @@ class ForLoopToLoop final : public Castable<ForLoopToLoop, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_FOR_LOOP_TO_LOOP_H_
diff --git a/src/tint/transform/for_loop_to_loop_test.cc b/src/tint/transform/for_loop_to_loop_test.cc
index 07fe2a9e45..84ffa98461 100644
--- a/src/tint/transform/for_loop_to_loop_test.cc
+++ b/src/tint/transform/for_loop_to_loop_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using ForLoopToLoopTest = TransformTest;
@@ -370,5 +369,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/glsl.cc b/src/tint/transform/glsl.cc
index df6b6b3b61..f0120e8fb8 100644
--- a/src/tint/transform/glsl.cc
+++ b/src/tint/transform/glsl.cc
@@ -42,8 +42,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Glsl);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Glsl::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 Glsl::Glsl() = default;
 Glsl::~Glsl() = default;
@@ -143,5 +142,4 @@ Glsl::Config::Config(const std::string& entry_point_in,
 Glsl::Config::Config(const Config&) = default;
 Glsl::Config::~Config() = default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/glsl.h b/src/tint/transform/glsl.h
index 414f871055..73bc76b801 100644
--- a/src/tint/transform/glsl.h
+++ b/src/tint/transform/glsl.h
@@ -19,12 +19,12 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 class CloneContext;
+}
 
-namespace transform {
+namespace tint::transform {
 
 /// Glsl is a transform used to sanitize a Program for use with the Glsl writer.
 /// Passing a non-sanitized Program to the Glsl writer will result in undefined
@@ -70,7 +70,6 @@ class Glsl final : public Castable<Glsl, Transform> {
   Output Run(const Program* program, const DataMap& data = {}) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_GLSL_H_
diff --git a/src/tint/transform/glsl_test.cc b/src/tint/transform/glsl_test.cc
index 5a2d872de8..555701b59a 100644
--- a/src/tint/transform/glsl_test.cc
+++ b/src/tint/transform/glsl_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using GlslTest = TransformTest;
@@ -37,5 +36,4 @@ fn unused_entry_point() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/localize_struct_array_assignment.cc b/src/tint/transform/localize_struct_array_assignment.cc
index ff2289bc1a..e888c017ad 100644
--- a/src/tint/transform/localize_struct_array_assignment.cc
+++ b/src/tint/transform/localize_struct_array_assignment.cc
@@ -30,8 +30,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::LocalizeStructArrayAssignment);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Private implementation of LocalizeStructArrayAssignment transform
 class LocalizeStructArrayAssignment::State {
@@ -220,5 +219,4 @@ void LocalizeStructArrayAssignment::Run(CloneContext& ctx,
   state.Run();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/localize_struct_array_assignment.h b/src/tint/transform/localize_struct_array_assignment.h
index ec5faa6053..2c45203e1b 100644
--- a/src/tint/transform/localize_struct_array_assignment.h
+++ b/src/tint/transform/localize_struct_array_assignment.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// This transforms replaces assignment to dynamically-indexed fixed-size arrays
 /// in structs on shader-local variables with code that copies the arrays to a
@@ -52,7 +51,6 @@ class LocalizeStructArrayAssignment
   class State;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_LOCALIZE_STRUCT_ARRAY_ASSIGNMENT_H_
diff --git a/src/tint/transform/localize_struct_array_assignment_test.cc b/src/tint/transform/localize_struct_array_assignment_test.cc
index 2c75f762ba..d202785130 100644
--- a/src/tint/transform/localize_struct_array_assignment_test.cc
+++ b/src/tint/transform/localize_struct_array_assignment_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using LocalizeStructArrayAssignmentTest = TransformTest;
@@ -865,5 +864,4 @@ fn main() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/loop_to_for_loop.cc b/src/tint/transform/loop_to_for_loop.cc
index ac205c0692..d01ac48e26 100644
--- a/src/tint/transform/loop_to_for_loop.cc
+++ b/src/tint/transform/loop_to_for_loop.cc
@@ -25,8 +25,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::LoopToForLoop);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 bool IsBlockWithSingleBreak(const ast::BlockStatement* block) {
@@ -141,5 +140,4 @@ void LoopToForLoop::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/loop_to_for_loop.h b/src/tint/transform/loop_to_for_loop.h
index 94e09f64ab..b6482aebed 100644
--- a/src/tint/transform/loop_to_for_loop.h
+++ b/src/tint/transform/loop_to_for_loop.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// LoopToForLoop is a Transform that attempts to convert WGSL `loop {}`
 /// statements into a for-loop statement.
@@ -48,7 +47,6 @@ class LoopToForLoop : public Castable<LoopToForLoop, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_LOOP_TO_FOR_LOOP_H_
diff --git a/src/tint/transform/loop_to_for_loop_test.cc b/src/tint/transform/loop_to_for_loop_test.cc
index df51e10bee..c34b0e84b0 100644
--- a/src/tint/transform/loop_to_for_loop_test.cc
+++ b/src/tint/transform/loop_to_for_loop_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using LoopToForLoopTest = TransformTest;
@@ -304,5 +303,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/manager.cc b/src/tint/transform/manager.cc
index 158a28e26c..a52f17531a 100644
--- a/src/tint/transform/manager.cc
+++ b/src/tint/transform/manager.cc
@@ -26,8 +26,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Manager);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 Manager::Manager() = default;
 Manager::~Manager() = default;
@@ -82,5 +81,4 @@ Output Manager::Run(const Program* program, const DataMap& data) const {
   return out;
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/manager.h b/src/tint/transform/manager.h
index 092b568f68..fb614d3920 100644
--- a/src/tint/transform/manager.h
+++ b/src/tint/transform/manager.h
@@ -21,8 +21,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// A collection of Transforms that act as a single Transform.
 /// The inner transforms will execute in the appended order.
@@ -58,7 +57,6 @@ class Manager : public Castable<Manager, Transform> {
   std::vector<std::unique_ptr<Transform>> transforms_;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_MANAGER_H_
diff --git a/src/tint/transform/module_scope_var_to_entry_point_param.cc b/src/tint/transform/module_scope_var_to_entry_point_param.cc
index e213c45b8a..b510d7d1df 100644
--- a/src/tint/transform/module_scope_var_to_entry_point_param.cc
+++ b/src/tint/transform/module_scope_var_to_entry_point_param.cc
@@ -28,8 +28,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::ModuleScopeVarToEntryPointParam);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 // Returns `true` if `type` is or contains a matrix type.
 bool ContainsMatrix(const sem::Type* type) {
@@ -395,5 +394,4 @@ void ModuleScopeVarToEntryPointParam::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/module_scope_var_to_entry_point_param.h b/src/tint/transform/module_scope_var_to_entry_point_param.h
index 334fcd4e12..8297057798 100644
--- a/src/tint/transform/module_scope_var_to_entry_point_param.h
+++ b/src/tint/transform/module_scope_var_to_entry_point_param.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Move module-scope variables into the entry point as parameters.
 ///
@@ -90,7 +89,6 @@ class ModuleScopeVarToEntryPointParam
   struct State;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_MODULE_SCOPE_VAR_TO_ENTRY_POINT_PARAM_H_
diff --git a/src/tint/transform/module_scope_var_to_entry_point_param_test.cc b/src/tint/transform/module_scope_var_to_entry_point_param_test.cc
index 3997d9afa4..3089355b5f 100644
--- a/src/tint/transform/module_scope_var_to_entry_point_param_test.cc
+++ b/src/tint/transform/module_scope_var_to_entry_point_param_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using ModuleScopeVarToEntryPointParamTest = TransformTest;
@@ -1166,5 +1165,4 @@ TEST_F(ModuleScopeVarToEntryPointParamTest, EmtpyModule) {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/multiplanar_external_texture.cc b/src/tint/transform/multiplanar_external_texture.cc
index 801c593bdc..00466ac139 100644
--- a/src/tint/transform/multiplanar_external_texture.cc
+++ b/src/tint/transform/multiplanar_external_texture.cc
@@ -27,8 +27,7 @@ TINT_INSTANTIATE_TYPEINFO(tint::transform::MultiplanarExternalTexture);
 TINT_INSTANTIATE_TYPEINFO(
     tint::transform::MultiplanarExternalTexture::NewBindingPoints);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 /// This struct stores symbols for new bindings created as a result of
@@ -450,5 +449,4 @@ void MultiplanarExternalTexture::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/multiplanar_external_texture.h b/src/tint/transform/multiplanar_external_texture.h
index 240d520d01..ab2298ced0 100644
--- a/src/tint/transform/multiplanar_external_texture.h
+++ b/src/tint/transform/multiplanar_external_texture.h
@@ -23,8 +23,7 @@
 #include "src/tint/sem/builtin_type.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// BindingPoint is an alias to sem::BindingPoint
 using BindingPoint = sem::BindingPoint;
@@ -96,7 +95,6 @@ class MultiplanarExternalTexture
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_MULTIPLANAR_EXTERNAL_TEXTURE_H_
diff --git a/src/tint/transform/multiplanar_external_texture_test.cc b/src/tint/transform/multiplanar_external_texture_test.cc
index 85150a623a..b0a79d6180 100644
--- a/src/tint/transform/multiplanar_external_texture_test.cc
+++ b/src/tint/transform/multiplanar_external_texture_test.cc
@@ -15,8 +15,7 @@
 #include "src/tint/transform/multiplanar_external_texture.h"
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using MultiplanarExternalTextureTest = TransformTest;
@@ -1293,5 +1292,4 @@ type ET = texture_external;
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/num_workgroups_from_uniform.cc b/src/tint/transform/num_workgroups_from_uniform.cc
index db71158ba6..72f7fb82eb 100644
--- a/src/tint/transform/num_workgroups_from_uniform.cc
+++ b/src/tint/transform/num_workgroups_from_uniform.cc
@@ -27,8 +27,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::NumWorkgroupsFromUniform);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::NumWorkgroupsFromUniform::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 /// Accessor describes the identifiers used in a member accessor that is being
 /// used to retrieve the num_workgroups builtin from a parameter.
@@ -166,5 +165,4 @@ NumWorkgroupsFromUniform::Config::Config(sem::BindingPoint ubo_bp)
 NumWorkgroupsFromUniform::Config::Config(const Config&) = default;
 NumWorkgroupsFromUniform::Config::~Config() = default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/num_workgroups_from_uniform.h b/src/tint/transform/num_workgroups_from_uniform.h
index 0d20a021b1..4cbecb6880 100644
--- a/src/tint/transform/num_workgroups_from_uniform.h
+++ b/src/tint/transform/num_workgroups_from_uniform.h
@@ -18,12 +18,12 @@
 #include "src/tint/sem/binding_point.h"
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-
 // Forward declarations
+namespace tint {
 class CloneContext;
+}
 
-namespace transform {
+namespace tint::transform {
 
 /// NumWorkgroupsFromUniform is a transform that implements the `num_workgroups`
 /// builtin by loading it from a uniform buffer.
@@ -84,7 +84,6 @@ class NumWorkgroupsFromUniform
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_NUM_WORKGROUPS_FROM_UNIFORM_H_
diff --git a/src/tint/transform/num_workgroups_from_uniform_test.cc b/src/tint/transform/num_workgroups_from_uniform_test.cc
index 6290d0b70b..734d11be84 100644
--- a/src/tint/transform/num_workgroups_from_uniform_test.cc
+++ b/src/tint/transform/num_workgroups_from_uniform_test.cc
@@ -20,8 +20,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using NumWorkgroupsFromUniformTest = TransformTest;
@@ -452,5 +451,4 @@ fn main(tint_symbol : tint_symbol_1) {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/promote_initializers_to_const_var_test.cc b/src/tint/transform/promote_initializers_to_const_var_test.cc
index b99f965e13..87b9edc8bf 100644
--- a/src/tint/transform/promote_initializers_to_const_var_test.cc
+++ b/src/tint/transform/promote_initializers_to_const_var_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using PromoteInitializersToConstVarTest = TransformTest;
@@ -623,5 +622,4 @@ let module_arr : array<f32, 4u> = array<f32, 4u>(0.0, 1.0, 2.0, 3.0);
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/promote_side_effects_to_decl_test.cc b/src/tint/transform/promote_side_effects_to_decl_test.cc
index 0f8c59a89b..299d7066c8 100644
--- a/src/tint/transform/promote_side_effects_to_decl_test.cc
+++ b/src/tint/transform/promote_side_effects_to_decl_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using PromoteSideEffectsToDeclTest = TransformTest;
@@ -4008,5 +4007,4 @@ fn f() {
   EXPECT_EQ(expect, str(got));
 }
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/remove_continue_in_switch_test.cc b/src/tint/transform/remove_continue_in_switch_test.cc
index cd485b0c7d..70f167debb 100644
--- a/src/tint/transform/remove_continue_in_switch_test.cc
+++ b/src/tint/transform/remove_continue_in_switch_test.cc
@@ -15,8 +15,7 @@
 #include "src/tint/transform/remove_continue_in_switch.h"
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using RemoveContinueInSwitchTest = TransformTest;
@@ -561,5 +560,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/remove_phonies.cc b/src/tint/transform/remove_phonies.cc
index 35bad3f934..9904e348de 100644
--- a/src/tint/transform/remove_phonies.cc
+++ b/src/tint/transform/remove_phonies.cc
@@ -30,8 +30,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::RemovePhonies);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 struct SinkSignature {
@@ -152,5 +151,4 @@ void RemovePhonies::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/remove_phonies.h b/src/tint/transform/remove_phonies.h
index 16de70848d..6e355f18a4 100644
--- a/src/tint/transform/remove_phonies.h
+++ b/src/tint/transform/remove_phonies.h
@@ -20,8 +20,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// RemovePhonies is a Transform that removes all phony-assignment statements,
 /// while preserving function call expressions in the RHS of the assignment that
@@ -52,7 +51,6 @@ class RemovePhonies : public Castable<RemovePhonies, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_REMOVE_PHONIES_H_
diff --git a/src/tint/transform/remove_phonies_test.cc b/src/tint/transform/remove_phonies_test.cc
index dc6099c126..e6faa3e2dc 100644
--- a/src/tint/transform/remove_phonies_test.cc
+++ b/src/tint/transform/remove_phonies_test.cc
@@ -20,8 +20,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using RemovePhoniesTest = TransformTest;
@@ -427,5 +426,4 @@ struct S {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/remove_unreachable_statements.cc b/src/tint/transform/remove_unreachable_statements.cc
index fd56ef0e29..3e13ad7aaa 100644
--- a/src/tint/transform/remove_unreachable_statements.cc
+++ b/src/tint/transform/remove_unreachable_statements.cc
@@ -30,8 +30,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::RemoveUnreachableStatements);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 RemoveUnreachableStatements::RemoveUnreachableStatements() = default;
 
@@ -63,5 +62,4 @@ void RemoveUnreachableStatements::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/remove_unreachable_statements.h b/src/tint/transform/remove_unreachable_statements.h
index dfc9f155fc..a474efb49d 100644
--- a/src/tint/transform/remove_unreachable_statements.h
+++ b/src/tint/transform/remove_unreachable_statements.h
@@ -20,8 +20,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// RemoveUnreachableStatements is a Transform that removes all statements
 /// marked as unreachable.
@@ -52,7 +51,6 @@ class RemoveUnreachableStatements
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_REMOVE_UNREACHABLE_STATEMENTS_H_
diff --git a/src/tint/transform/remove_unreachable_statements_test.cc b/src/tint/transform/remove_unreachable_statements_test.cc
index 4e5670f45e..43c19508ad 100644
--- a/src/tint/transform/remove_unreachable_statements_test.cc
+++ b/src/tint/transform/remove_unreachable_statements_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using RemoveUnreachableStatementsTest = TransformTest;
@@ -567,5 +566,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/renamer_test.cc b/src/tint/transform/renamer_test.cc
index 70d43225b6..e3f9458ba7 100644
--- a/src/tint/transform/renamer_test.cc
+++ b/src/tint/transform/renamer_test.cc
@@ -19,8 +19,7 @@
 #include "gmock/gmock.h"
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 constexpr const char kUnicodeIdentifier[] =  // "𝖎𝖉𝖊𝖓𝖙𝖎𝖋𝖎𝖊𝖗123"
@@ -1459,5 +1458,4 @@ INSTANTIATE_TEST_SUITE_P(
         kUnicodeIdentifier));
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/robustness.cc b/src/tint/transform/robustness.cc
index 44b5f729e1..4a67d495f7 100644
--- a/src/tint/transform/robustness.cc
+++ b/src/tint/transform/robustness.cc
@@ -28,8 +28,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Robustness);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Robustness::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// State holds the current transform state
 struct Robustness::State {
@@ -316,5 +315,4 @@ void Robustness::Run(CloneContext& ctx, const DataMap& inputs, DataMap&) const {
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/robustness.h b/src/tint/transform/robustness.h
index 733cf47363..79ddf0891c 100644
--- a/src/tint/transform/robustness.h
+++ b/src/tint/transform/robustness.h
@@ -20,15 +20,12 @@
 #include "src/tint/transform/transform.h"
 
 // Forward declarations
-namespace tint {
-namespace ast {
+namespace tint::ast {
 class IndexAccessorExpression;
 class CallExpression;
-}  // namespace ast
-}  // namespace tint
+}  // namespace tint::ast
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// This transform is responsible for clamping all array accesses to be within
 /// the bounds of the array. Any access before the start of the array will clamp
@@ -82,7 +79,6 @@ class Robustness : public Castable<Robustness, Transform> {
   struct State;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_ROBUSTNESS_H_
diff --git a/src/tint/transform/robustness_test.cc b/src/tint/transform/robustness_test.cc
index 1e1dac6abb..db113b2281 100644
--- a/src/tint/transform/robustness_test.cc
+++ b/src/tint/transform/robustness_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using RobustnessTest = TransformTest;
@@ -1741,5 +1740,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/simplify_pointers.cc b/src/tint/transform/simplify_pointers.cc
index 715894bb6d..4cc9391efb 100644
--- a/src/tint/transform/simplify_pointers.cc
+++ b/src/tint/transform/simplify_pointers.cc
@@ -28,8 +28,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::SimplifyPointers);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 namespace {
 
@@ -235,5 +234,4 @@ void SimplifyPointers::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
   State(ctx).Run();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/simplify_pointers.h b/src/tint/transform/simplify_pointers.h
index 39ebc26fec..3bd49503ea 100644
--- a/src/tint/transform/simplify_pointers.h
+++ b/src/tint/transform/simplify_pointers.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// SimplifyPointers is a Transform that moves all usage of function-scope
 /// `let` statements of a pointer type into their places of usage, while also
@@ -54,7 +53,6 @@ class SimplifyPointers : public Castable<SimplifyPointers, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_SIMPLIFY_POINTERS_H_
diff --git a/src/tint/transform/simplify_pointers_test.cc b/src/tint/transform/simplify_pointers_test.cc
index 0e9d44bc5e..6266b6f952 100644
--- a/src/tint/transform/simplify_pointers_test.cc
+++ b/src/tint/transform/simplify_pointers_test.cc
@@ -17,8 +17,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/transform/unshadow.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using SimplifyPointersTest = TransformTest;
@@ -366,5 +365,4 @@ fn main() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/single_entry_point.cc b/src/tint/transform/single_entry_point.cc
index 62a662457c..fe92483b17 100644
--- a/src/tint/transform/single_entry_point.cc
+++ b/src/tint/transform/single_entry_point.cc
@@ -24,8 +24,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::SingleEntryPoint);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::SingleEntryPoint::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 SingleEntryPoint::SingleEntryPoint() = default;
 
@@ -113,5 +112,4 @@ SingleEntryPoint::Config::~Config() = default;
 SingleEntryPoint::Config& SingleEntryPoint::Config::operator=(const Config&) =
     default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/single_entry_point.h b/src/tint/transform/single_entry_point.h
index 87807613ff..b5aed68f4c 100644
--- a/src/tint/transform/single_entry_point.h
+++ b/src/tint/transform/single_entry_point.h
@@ -19,8 +19,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Strip all but one entry point a module.
 ///
@@ -66,7 +65,6 @@ class SingleEntryPoint : public Castable<SingleEntryPoint, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_SINGLE_ENTRY_POINT_H_
diff --git a/src/tint/transform/single_entry_point_test.cc b/src/tint/transform/single_entry_point_test.cc
index b6a9d35bb4..750f5c3ba5 100644
--- a/src/tint/transform/single_entry_point_test.cc
+++ b/src/tint/transform/single_entry_point_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using SingleEntryPointTest = TransformTest;
@@ -513,5 +512,4 @@ fn comp_main1() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/test_helper.h b/src/tint/transform/test_helper.h
index 8a36df10d5..7d7015c096 100644
--- a/src/tint/transform/test_helper.h
+++ b/src/tint/transform/test_helper.h
@@ -25,8 +25,7 @@
 #include "src/tint/transform/manager.h"
 #include "src/tint/writer/wgsl/generator.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// @param program the program to get an output WGSL string from
 /// @returns the output program as a WGSL string, or an error string if the
@@ -148,7 +147,6 @@ using TransformTest = TransformTestBase<testing::Test>;
 template <typename T>
 using TransformTestWithParam = TransformTestBase<testing::TestWithParam<T>>;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_TEST_HELPER_H_
diff --git a/src/tint/transform/transform.cc b/src/tint/transform/transform.cc
index 2254ce493e..018bc95ca3 100644
--- a/src/tint/transform/transform.cc
+++ b/src/tint/transform/transform.cc
@@ -28,8 +28,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Transform);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Data);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 Data::Data() = default;
 Data::Data(const Data&) = default;
@@ -156,5 +155,4 @@ const ast::Type* Transform::CreateASTTypeFor(CloneContext& ctx,
   return nullptr;
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/transform.h b/src/tint/transform/transform.h
index 199cb86596..50518162f9 100644
--- a/src/tint/transform/transform.h
+++ b/src/tint/transform/transform.h
@@ -22,8 +22,7 @@
 #include "src/tint/castable.h"
 #include "src/tint/program.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Data is the base class for transforms that accept extra input or emit extra
 /// output information along with a Program.
@@ -193,7 +192,6 @@ class Transform : public Castable<Transform> {
                                            const sem::Type* ty);
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_TRANSFORM_H_
diff --git a/src/tint/transform/transform_test.cc b/src/tint/transform/transform_test.cc
index 318778dc27..c100c09283 100644
--- a/src/tint/transform/transform_test.cc
+++ b/src/tint/transform/transform_test.cc
@@ -18,8 +18,7 @@
 
 #include "gtest/gtest.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 // Inherit from Transform so we have access to protected methods
@@ -119,5 +118,4 @@ TEST_F(CreateASTTypeForTest, Struct) {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/unshadow.cc b/src/tint/transform/unshadow.cc
index 017258f02f..9c28675147 100644
--- a/src/tint/transform/unshadow.cc
+++ b/src/tint/transform/unshadow.cc
@@ -26,8 +26,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::Unshadow);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// The PIMPL state for the Unshadow transform
 struct Unshadow::State {
@@ -95,5 +94,4 @@ void Unshadow::Run(CloneContext& ctx, const DataMap&, DataMap&) const {
   State(ctx).Run();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/unshadow.h b/src/tint/transform/unshadow.h
index f8119a993d..bfea67763c 100644
--- a/src/tint/transform/unshadow.h
+++ b/src/tint/transform/unshadow.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Unshadow is a Transform that renames any variables that shadow another
 /// variable.
@@ -44,7 +43,6 @@ class Unshadow : public Castable<Unshadow, Transform> {
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_UNSHADOW_H_
diff --git a/src/tint/transform/unshadow_test.cc b/src/tint/transform/unshadow_test.cc
index 6ca1375ebc..ccb9fba8a4 100644
--- a/src/tint/transform/unshadow_test.cc
+++ b/src/tint/transform/unshadow_test.cc
@@ -16,8 +16,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using UnshadowTest = TransformTest;
@@ -605,5 +604,4 @@ type a = i32;
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/unwind_discard_functions_test.cc b/src/tint/transform/unwind_discard_functions_test.cc
index ae0a1f1395..0b8c0fcae0 100644
--- a/src/tint/transform/unwind_discard_functions_test.cc
+++ b/src/tint/transform/unwind_discard_functions_test.cc
@@ -16,8 +16,7 @@
 #include "src/tint/transform/promote_side_effects_to_decl.h"
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using UnwindDiscardFunctionsTest = TransformTest;
@@ -1417,5 +1416,4 @@ fn main(@builtin(position) coord_in : vec4<f32>) -> @location(0) vec4<f32> {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/var_for_dynamic_index_test.cc b/src/tint/transform/var_for_dynamic_index_test.cc
index 2bd8a6e3ae..a222ad737b 100644
--- a/src/tint/transform/var_for_dynamic_index_test.cc
+++ b/src/tint/transform/var_for_dynamic_index_test.cc
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using VarForDynamicIndexTest = TransformTest;
@@ -549,5 +548,4 @@ fn f() {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/vectorize_scalar_matrix_constructors.cc b/src/tint/transform/vectorize_scalar_matrix_constructors.cc
index bccc50bf76..8af027284d 100644
--- a/src/tint/transform/vectorize_scalar_matrix_constructors.cc
+++ b/src/tint/transform/vectorize_scalar_matrix_constructors.cc
@@ -23,8 +23,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::VectorizeScalarMatrixConstructors);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 VectorizeScalarMatrixConstructors::VectorizeScalarMatrixConstructors() =
     default;
@@ -93,5 +92,4 @@ void VectorizeScalarMatrixConstructors::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/vectorize_scalar_matrix_constructors.h b/src/tint/transform/vectorize_scalar_matrix_constructors.h
index 44754e153d..f1abb4fcd9 100644
--- a/src/tint/transform/vectorize_scalar_matrix_constructors.h
+++ b/src/tint/transform/vectorize_scalar_matrix_constructors.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// A transform that converts scalar matrix constructors to the vector form.
 class VectorizeScalarMatrixConstructors
@@ -48,7 +47,6 @@ class VectorizeScalarMatrixConstructors
            DataMap& outputs) const override;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_VECTORIZE_SCALAR_MATRIX_CONSTRUCTORS_H_
diff --git a/src/tint/transform/vectorize_scalar_matrix_constructors_test.cc b/src/tint/transform/vectorize_scalar_matrix_constructors_test.cc
index d6d496cb3d..edd68e254d 100644
--- a/src/tint/transform/vectorize_scalar_matrix_constructors_test.cc
+++ b/src/tint/transform/vectorize_scalar_matrix_constructors_test.cc
@@ -20,8 +20,7 @@
 #include "src/tint/transform/test_helper.h"
 #include "src/tint/utils/string.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using VectorizeScalarMatrixConstructorsTest =
@@ -120,5 +119,4 @@ INSTANTIATE_TEST_SUITE_P(VectorizeScalarMatrixConstructorsTest,
                                          std::make_pair(4, 4)));
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/vertex_pulling.cc b/src/tint/transform/vertex_pulling.cc
index e0d3128e88..420076784f 100644
--- a/src/tint/transform/vertex_pulling.cc
+++ b/src/tint/transform/vertex_pulling.cc
@@ -28,8 +28,7 @@
 TINT_INSTANTIATE_TYPEINFO(tint::transform::VertexPulling);
 TINT_INSTANTIATE_TYPEINFO(tint::transform::VertexPulling::Config);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 namespace {
 
@@ -958,5 +957,4 @@ VertexBufferLayoutDescriptor& VertexBufferLayoutDescriptor::operator=(
 
 VertexBufferLayoutDescriptor::~VertexBufferLayoutDescriptor() = default;
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/vertex_pulling.h b/src/tint/transform/vertex_pulling.h
index 95bc25d1ba..ec0769b9b5 100644
--- a/src/tint/transform/vertex_pulling.h
+++ b/src/tint/transform/vertex_pulling.h
@@ -22,8 +22,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// Describes the format of data in a vertex buffer
 enum class VertexFormat {
@@ -180,7 +179,6 @@ class VertexPulling : public Castable<VertexPulling, Transform> {
   Config cfg_;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_VERTEX_PULLING_H_
diff --git a/src/tint/transform/vertex_pulling_test.cc b/src/tint/transform/vertex_pulling_test.cc
index 313133d205..3c19aa6d48 100644
--- a/src/tint/transform/vertex_pulling_test.cc
+++ b/src/tint/transform/vertex_pulling_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using VertexPullingTest = TransformTest;
@@ -1286,5 +1285,4 @@ fn main(@builtin(vertex_index) tint_pulling_vertex_index : u32) -> @builtin(posi
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/wrap_arrays_in_structs.cc b/src/tint/transform/wrap_arrays_in_structs.cc
index f910497165..7cf3fcb770 100644
--- a/src/tint/transform/wrap_arrays_in_structs.cc
+++ b/src/tint/transform/wrap_arrays_in_structs.cc
@@ -26,8 +26,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::WrapArraysInStructs);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 WrapArraysInStructs::WrappedArrayInfo::WrappedArrayInfo() = default;
 WrapArraysInStructs::WrappedArrayInfo::WrappedArrayInfo(
@@ -167,5 +166,4 @@ WrapArraysInStructs::WrappedArrayInfo WrapArraysInStructs::WrapArray(
   });
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/wrap_arrays_in_structs.h b/src/tint/transform/wrap_arrays_in_structs.h
index 0d97a442eb..a256ff8dca 100644
--- a/src/tint/transform/wrap_arrays_in_structs.h
+++ b/src/tint/transform/wrap_arrays_in_structs.h
@@ -21,14 +21,11 @@
 #include "src/tint/transform/transform.h"
 
 // Forward declarations
-namespace tint {
-namespace ast {
+namespace tint::ast {
 class Type;
-}  // namespace ast
-}  // namespace tint
+}  // namespace tint::ast
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// WrapArraysInStructs is a transform that replaces all array types with a
 /// structure holding a single field of that array type.
@@ -89,7 +86,6 @@ class WrapArraysInStructs : public Castable<WrapArraysInStructs, Transform> {
       const sem::Array* array) const;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_WRAP_ARRAYS_IN_STRUCTS_H_
diff --git a/src/tint/transform/wrap_arrays_in_structs_test.cc b/src/tint/transform/wrap_arrays_in_structs_test.cc
index 7627484ac0..7ba884cea3 100644
--- a/src/tint/transform/wrap_arrays_in_structs_test.cc
+++ b/src/tint/transform/wrap_arrays_in_structs_test.cc
@@ -19,8 +19,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using WrapArraysInStructsTest = TransformTest;
@@ -420,5 +419,4 @@ type T0 = i32;
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/zero_init_workgroup_memory.cc b/src/tint/transform/zero_init_workgroup_memory.cc
index e0519887ac..8441e17560 100644
--- a/src/tint/transform/zero_init_workgroup_memory.cc
+++ b/src/tint/transform/zero_init_workgroup_memory.cc
@@ -30,8 +30,7 @@
 
 TINT_INSTANTIATE_TYPEINFO(tint::transform::ZeroInitWorkgroupMemory);
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// PIMPL state for the ZeroInitWorkgroupMemory transform
 struct ZeroInitWorkgroupMemory::State {
@@ -457,5 +456,4 @@ void ZeroInitWorkgroupMemory::Run(CloneContext& ctx,
   ctx.Clone();
 }
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
diff --git a/src/tint/transform/zero_init_workgroup_memory.h b/src/tint/transform/zero_init_workgroup_memory.h
index 6069b12a1d..33ae52ce7b 100644
--- a/src/tint/transform/zero_init_workgroup_memory.h
+++ b/src/tint/transform/zero_init_workgroup_memory.h
@@ -17,8 +17,7 @@
 
 #include "src/tint/transform/transform.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 
 /// ZeroInitWorkgroupMemory is a transform that injects code at the top of entry
 /// points to zero-initialize workgroup memory used by that entry point (and all
@@ -53,7 +52,6 @@ class ZeroInitWorkgroupMemory
   struct State;
 };
 
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform
 
 #endif  // SRC_TINT_TRANSFORM_ZERO_INIT_WORKGROUP_MEMORY_H_
diff --git a/src/tint/transform/zero_init_workgroup_memory_test.cc b/src/tint/transform/zero_init_workgroup_memory_test.cc
index cfe46479ec..32c73db1e6 100644
--- a/src/tint/transform/zero_init_workgroup_memory_test.cc
+++ b/src/tint/transform/zero_init_workgroup_memory_test.cc
@@ -18,8 +18,7 @@
 
 #include "src/tint/transform/test_helper.h"
 
-namespace tint {
-namespace transform {
+namespace tint::transform {
 namespace {
 
 using ZeroInitWorkgroupMemoryTest = TransformTest;
@@ -1377,5 +1376,4 @@ struct S {
 }
 
 }  // namespace
-}  // namespace transform
-}  // namespace tint
+}  // namespace tint::transform