diff --git a/mlir/include/mlir/IR/BuiltinOps.td b/mlir/include/mlir/IR/BuiltinOps.td
--- a/mlir/include/mlir/IR/BuiltinOps.td
+++ b/mlir/include/mlir/IR/BuiltinOps.td
@@ -115,7 +115,7 @@
     /// Returns the region on the current operation that is callable. This may
     /// return null in the case of an external callable object, e.g. an external
     /// function.
-    Region *getCallableRegion() { return isExternal() ? nullptr : &getBody(); }
+    ::mlir::Region *getCallableRegion() { return isExternal() ? nullptr : &getBody(); }
 
     /// Returns the results types that the callable region produces when
     /// executed.
diff --git a/mlir/include/mlir/IR/OpBase.td b/mlir/include/mlir/IR/OpBase.td
--- a/mlir/include/mlir/IR/OpBase.td
+++ b/mlir/include/mlir/IR/OpBase.td
@@ -1618,7 +1618,7 @@
 }
 
 // Derived attribute that returns a mlir::Type.
-class DerivedTypeAttr<code body> : DerivedAttr<"Type", body> {
+class DerivedTypeAttr<code body> : DerivedAttr<"::mlir::Type", body> {
   let convertFromStorage = "::mlir::TypeAttr::get($_self)";
 }
 
diff --git a/mlir/include/mlir/IR/RegionKindInterface.td b/mlir/include/mlir/IR/RegionKindInterface.td
--- a/mlir/include/mlir/IR/RegionKindInterface.td
+++ b/mlir/include/mlir/IR/RegionKindInterface.td
@@ -33,7 +33,7 @@
       /*desc=*/[{
         Return the kind of the region with the given index inside this operation.
       }],
-      /*retTy=*/"RegionKind",
+      /*retTy=*/"::mlir::RegionKind",
       /*methodName=*/"getRegionKind",
       /*args=*/(ins "unsigned":$index)
     >,
@@ -44,7 +44,7 @@
       /*methodName=*/"hasSSADominance",
       /*args=*/(ins "unsigned":$index),
       /*methodBody=*/[{
-        return getRegionKind(index) == RegionKind::SSACFG;
+        return getRegionKind(index) == ::mlir::RegionKind::SSACFG;
       }]
     >,
   ];
diff --git a/mlir/include/mlir/Interfaces/InferTypeOpInterface.td b/mlir/include/mlir/Interfaces/InferTypeOpInterface.td
--- a/mlir/include/mlir/Interfaces/InferTypeOpInterface.td
+++ b/mlir/include/mlir/Interfaces/InferTypeOpInterface.td
@@ -168,10 +168,10 @@
         rank of the corresponding result. If the shape of a particular
         result cannot be computed it must be empty.
       }],
-      /*retTy=*/"LogicalResult",
+      /*retTy=*/"::mlir::LogicalResult",
       /*methodName=*/"reifyResultShapes",
       /*args=*/(ins "::mlir::OpBuilder &":$builder,
-        "ReifiedRankedShapedTypeDims &":$reifiedReturnShapes)
+        "::mlir::ReifiedRankedShapedTypeDims &":$reifiedReturnShapes)
     >
   ];
 }
diff --git a/mlir/test/lib/Dialect/Test/TestAttributes.cpp b/mlir/test/lib/Dialect/Test/TestAttributes.cpp
--- a/mlir/test/lib/Dialect/Test/TestAttributes.cpp
+++ b/mlir/test/lib/Dialect/Test/TestAttributes.cpp
@@ -21,7 +21,7 @@
 #include "llvm/ADT/TypeSwitch.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 //===----------------------------------------------------------------------===//
 // AttrWithSelfTypeParamAttr
diff --git a/mlir/test/lib/Dialect/Test/TestDialect.h b/mlir/test/lib/Dialect/Test/TestDialect.h
--- a/mlir/test/lib/Dialect/Test/TestDialect.h
+++ b/mlir/test/lib/Dialect/Test/TestDialect.h
@@ -45,11 +45,9 @@
 #define GET_OP_CLASSES
 #include "TestOps.h.inc"
 
-namespace mlir {
 namespace test {
-void registerTestDialect(DialectRegistry &registry);
-void populateTestReductionPatterns(RewritePatternSet &patterns);
-} // namespace test
-} // namespace mlir
+void registerTestDialect(::mlir::DialectRegistry &registry);
+void populateTestReductionPatterns(::mlir::RewritePatternSet &patterns);
+} // end namespace test
 
 #endif // MLIR_TESTDIALECT_H
diff --git a/mlir/test/lib/Dialect/Test/TestDialect.cpp b/mlir/test/lib/Dialect/Test/TestDialect.cpp
--- a/mlir/test/lib/Dialect/Test/TestDialect.cpp
+++ b/mlir/test/lib/Dialect/Test/TestDialect.cpp
@@ -22,12 +22,14 @@
 #include "mlir/Transforms/InliningUtils.h"
 #include "llvm/ADT/StringSwitch.h"
 
-using namespace mlir;
-using namespace mlir::test;
-
+// Include this before the using namespace lines below to
+// test that we don't have namespace dependencies.
 #include "TestOpsDialect.cpp.inc"
 
-void mlir::test::registerTestDialect(DialectRegistry &registry) {
+using namespace mlir;
+using namespace test;
+
+void test::registerTestDialect(DialectRegistry &registry) {
   registry.insert<TestDialect>();
 }
 
diff --git a/mlir/test/lib/Dialect/Test/TestInterfaces.td b/mlir/test/lib/Dialect/Test/TestInterfaces.td
--- a/mlir/test/lib/Dialect/Test/TestInterfaces.td
+++ b/mlir/test/lib/Dialect/Test/TestInterfaces.td
@@ -14,26 +14,26 @@
 
 // A type interface used to test the ODS generation of type interfaces.
 def TestTypeInterface : TypeInterface<"TestTypeInterface"> {
-  let cppNamespace = "::mlir::test";
+  let cppNamespace = "::test";
   let methods = [
     InterfaceMethod<"Prints the type name.",
-      "void", "printTypeA", (ins "Location":$loc), [{
+      "void", "printTypeA", (ins "::mlir::Location":$loc), [{
         emitRemark(loc) << $_type << " - TestA";
       }]
     >,
     InterfaceMethod<"Prints the type name.",
-      "void", "printTypeB", (ins "Location":$loc),
+      "void", "printTypeB", (ins "::mlir::Location":$loc),
       [{}], /*defaultImplementation=*/[{
         emitRemark(loc) << $_type << " - TestB";
       }]
     >,
     InterfaceMethod<"Prints the type name.",
-      "void", "printTypeC", (ins "Location":$loc)
+      "void", "printTypeC", (ins "::mlir::Location":$loc)
     >,
     // It should be possible to use the interface type name as result type
     // as well as in the implementation.
     InterfaceMethod<"Prints the type name and returns the type as interface.",
-      "TestTypeInterface", "printTypeRet", (ins "Location":$loc),
+      "TestTypeInterface", "printTypeRet", (ins "::mlir::Location":$loc),
       [{}], /*defaultImplementation=*/[{
         emitRemark(loc) << $_type << " - TestRet";
         return $_type;
@@ -42,13 +42,13 @@
   ];
   let extraClassDeclaration = [{
     /// Prints the type name.
-    void printTypeD(Location loc) const {
+    void printTypeD(::mlir::Location loc) const {
       emitRemark(loc) << *this << " - TestD";
     }
   }];
   let extraTraitClassDeclaration = [{
     /// Prints the type name.
-    void printTypeE(Location loc) const {
+    void printTypeE(::mlir::Location loc) const {
       emitRemark(loc) << $_type << " - TestE";
     }
   }];
diff --git a/mlir/test/lib/Dialect/Test/TestOps.td b/mlir/test/lib/Dialect/Test/TestOps.td
--- a/mlir/test/lib/Dialect/Test/TestOps.td
+++ b/mlir/test/lib/Dialect/Test/TestOps.td
@@ -24,7 +24,7 @@
 
 def Test_Dialect : Dialect {
   let name = "test";
-  let cppNamespace = "::mlir::test";
+  let cppNamespace = "::test";
   let hasCanonicalizer = 1;
   let hasConstantMaterializer = 1;
   let hasOperationAttrVerify = 1;
@@ -38,16 +38,16 @@
     void registerAttributes();
     void registerTypes();
 
-    Attribute parseAttribute(DialectAsmParser &parser,
-                             Type type) const override;
-    void printAttribute(Attribute attr,
-                        DialectAsmPrinter &printer) const override;
+    ::mlir::Attribute parseAttribute(::mlir::DialectAsmParser &parser,
+                             ::mlir::Type type) const override;
+    void printAttribute(::mlir::Attribute attr,
+                        ::mlir::DialectAsmPrinter &printer) const override;
 
     // Provides a custom printing/parsing for some operations.
-    Optional<ParseOpHook>
-      getParseOperationHook(StringRef opName) const override;
-    LogicalResult printOperation(Operation *op,
-                                 OpAsmPrinter &printer) const override;
+    ::llvm::Optional<ParseOpHook>
+      getParseOperationHook(::llvm::StringRef opName) const override;
+    ::mlir::LogicalResult printOperation(::mlir::Operation *op,
+                                 ::mlir::OpAsmPrinter &printer) const override;
   private:
     // Storage for a custom fallback interface.
     void *fallbackEffectOpInterfaces;
@@ -117,8 +117,8 @@
 }
 
 def TEST_TestType : DialectType<Test_Dialect,
-    CPred<"$_self.isa<::mlir::test::TestType>()">, "test">,
-    BuildableType<"$_builder.getType<::mlir::test::TestType>()">;
+    CPred<"$_self.isa<::test::TestType>()">, "test">,
+    BuildableType<"$_builder.getType<::test::TestType>()">;
 
 //===----------------------------------------------------------------------===//
 // Test Symbols
@@ -372,8 +372,8 @@
     operand_range getArgOperands() { return inputs(); }
 
     /// Return the callee of this operation.
-    CallInterfaceCallable getCallableForCallee() {
-      return (*this)->getAttrOfType<SymbolRefAttr>("callee");
+    ::mlir::CallInterfaceCallable getCallableForCallee() {
+      return (*this)->getAttrOfType<::mlir::SymbolRefAttr>("callee");
     }
   }];
 }
@@ -384,9 +384,9 @@
   let results = (outs FunctionType);
 
   let extraClassDeclaration = [{
-    Region *getCallableRegion() { return &body(); }
-    ArrayRef<Type> getCallableResults() {
-      return getType().cast<FunctionType>().getResults();
+    ::mlir::Region *getCallableRegion() { return &body(); }
+    ::llvm::ArrayRef<::mlir::Type> getCallableResults() {
+      return getType().cast<::mlir::FunctionType>().getResults();
     }
   }];
 }
@@ -748,7 +748,7 @@
   let description = [{
     The "test.op_funcref" is a test op with a reference to a function symbol.
   }];
-  let builders = [OpBuilder<(ins "FuncOp":$function)>];
+  let builders = [OpBuilder<(ins "::mlir::FuncOp":$function)>];
 }
 
 // Pattern add the argument plus a increasing static number hidden in
@@ -898,10 +898,10 @@
 }
 def Constraint0 : AttrConstraint<
     CPred<"$_self.cast<ArrayAttr>()[0]."
-          "cast<IntegerAttr>().getInt() == 0">,
+          "cast<::mlir::IntegerAttr>().getInt() == 0">,
     "[0] == 0">;
 def Constraint1 : AttrConstraint<
-    CPred<"$_self.cast<ArrayAttr>()[1].cast<IntegerAttr>().getInt() == 1">,
+    CPred<"$_self.cast<ArrayAttr>()[1].cast<::mlir::IntegerAttr>().getInt() == 1">,
     "[1] == 1">;
 def : Pat<(OpAllAttrConstraint1
             AllAttrConstraintsOf<[Constraint0, Constraint1]>:$attr),
@@ -917,7 +917,7 @@
   let arguments = (ins AnyAttr:$value);
   let results = (outs AnyType);
   let extraClassDeclaration = [{
-    Attribute getValue() { return (*this)->getAttr("value"); }
+    ::mlir::Attribute getValue() { return (*this)->getAttr("value"); }
   }];
 
   let hasFolder = 1;
@@ -1268,7 +1268,7 @@
   // We will use this op in a nested result pattern, where we cannot deduce the
   // result type. So need to provide a builder not requiring result types.
   let builders = [
-    OpBuilder<(ins "IntegerAttr":$count),
+    OpBuilder<(ins "::mlir::IntegerAttr":$count),
     [{
       auto i32Type = $_builder.getIntegerType(32);
       $_state.addTypes(i32Type); // $output1
@@ -1936,8 +1936,8 @@
      attr-dict
   }];
   let extraClassDeclaration = [{
-    Value getSource() { return source(); }
-    Value getTarget() { return target(); }
+    ::mlir::Value getSource() { return source(); }
+    ::mlir::Value getTarget() { return target(); }
   }];
 }
 
@@ -2027,16 +2027,16 @@
                         AnyRegion:$elseRegion,
                         AnyRegion:$joinRegion);
   let extraClassDeclaration = [{
-    Block::BlockArgListType getThenArgs() {
+    ::mlir::Block::BlockArgListType getThenArgs() {
       return getBody(0)->getArguments();
     }
-    Block::BlockArgListType getElseArgs() {
+    ::mlir::Block::BlockArgListType getElseArgs() {
       return getBody(1)->getArguments();
     }
-    Block::BlockArgListType getJoinArgs() {
+    ::mlir::Block::BlockArgListType getJoinArgs() {
       return getBody(2)->getArguments();
     }
-    OperandRange getSuccessorEntryOperands(unsigned index);
+    ::mlir::OperandRange getSuccessorEntryOperands(unsigned index);
   }];
 }
 
@@ -2089,12 +2089,12 @@
   let results = (outs AnyType:$result);
 
   let extraClassDeclaration = [{
-    static LogicalResult inferReturnTypes(MLIRContext *,
-          Optional<Location> location, ValueRange operands,
-          DictionaryAttr attributes, RegionRange regions,
-          SmallVectorImpl<Type> &inferredReturnTypes) {
+    static ::mlir::LogicalResult inferReturnTypes(::mlir::MLIRContext *,
+          ::llvm::Optional<::mlir::Location> location, ::mlir::ValueRange operands,
+          ::mlir::DictionaryAttr attributes, ::mlir::RegionRange regions,
+          ::llvm::SmallVectorImpl<::mlir::Type> &inferredReturnTypes) {
       inferredReturnTypes.assign({operands[0].getType()});
-      return success();
+      return ::mlir::success();
     }
    }];
 }
diff --git a/mlir/test/lib/Dialect/Test/TestPatterns.cpp b/mlir/test/lib/Dialect/Test/TestPatterns.cpp
--- a/mlir/test/lib/Dialect/Test/TestPatterns.cpp
+++ b/mlir/test/lib/Dialect/Test/TestPatterns.cpp
@@ -17,7 +17,7 @@
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 // Native function for testing NativeCodeCall
 static Value chooseOperand(Value input1, Value input2, BoolAttr choice) {
@@ -67,7 +67,7 @@
 // Test Reduce Pattern Interface
 //===----------------------------------------------------------------------===//
 
-void mlir::test::populateTestReductionPatterns(RewritePatternSet &patterns) {
+void test::populateTestReductionPatterns(RewritePatternSet &patterns) {
   populateWithGenerated(patterns);
 }
 
diff --git a/mlir/test/lib/Dialect/Test/TestTraits.cpp b/mlir/test/lib/Dialect/Test/TestTraits.cpp
--- a/mlir/test/lib/Dialect/Test/TestTraits.cpp
+++ b/mlir/test/lib/Dialect/Test/TestTraits.cpp
@@ -11,7 +11,7 @@
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 //===----------------------------------------------------------------------===//
 // Trait Folder.
diff --git a/mlir/test/lib/Dialect/Test/TestTypeDefs.td b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
--- a/mlir/test/lib/Dialect/Test/TestTypeDefs.td
+++ b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
@@ -56,7 +56,7 @@
     ins
     "unsigned":$width,
     // SignednessSemantics is defined below.
-    "::mlir::test::TestIntegerType::SignednessSemantics":$signedness
+    "::test::TestIntegerType::SignednessSemantics":$signedness
   );
 
   // We define the printer inline.
@@ -84,7 +84,7 @@
     int width;
     if ($_parser.parseInteger(width)) return Type();
     if ($_parser.parseGreater()) return Type();
-    Location loc = $_parser.getEncodedSourceLoc($_parser.getNameLoc());
+    ::mlir::Location loc = $_parser.getEncodedSourceLoc($_parser.getNameLoc());
     return getChecked(loc, loc.getContext(), width, signedness);
   }];
 
@@ -114,7 +114,7 @@
     // An ArrayRef of something which requires allocation in the storage
     // constructor.
     ArrayRefOfSelfAllocationParameter<
-      "::mlir::test::FieldInfo", // FieldInfo is defined/declared in TestTypes.h.
+      "::test::FieldInfo", // FieldInfo is defined/declared in TestTypes.h.
       "Models struct fields">: $fields
   );
 
@@ -136,7 +136,7 @@
     llvm::SmallVector<FieldInfo, 4> parameters;
     if ($_parser.parseLess()) return Type();
     while (mlir::succeeded($_parser.parseOptionalLBrace())) {
-      StringRef name;
+      llvm::StringRef name;
       if ($_parser.parseKeyword(&name)) return Type();
       if ($_parser.parseComma()) return Type();
       Type type;
@@ -166,12 +166,12 @@
   let mnemonic = "test_type_with_layout";
   let parameters = (ins "unsigned":$key);
   let extraClassDeclaration = [{
-    LogicalResult verifyEntries(DataLayoutEntryListRef params,
-                                Location loc) const;
+    ::mlir::LogicalResult verifyEntries(::mlir::DataLayoutEntryListRef params,
+                                ::mlir::Location loc) const;
 
   private:
-    unsigned extractKind(DataLayoutEntryListRef params,
-                         StringRef expectedKind) const;
+    unsigned extractKind(::mlir::DataLayoutEntryListRef params,
+                         ::llvm::StringRef expectedKind) const;
 
   public:
   }];
diff --git a/mlir/test/lib/Dialect/Test/TestTypes.h b/mlir/test/lib/Dialect/Test/TestTypes.h
--- a/mlir/test/lib/Dialect/Test/TestTypes.h
+++ b/mlir/test/lib/Dialect/Test/TestTypes.h
@@ -23,81 +23,77 @@
 #include "mlir/IR/Types.h"
 #include "mlir/Interfaces/DataLayoutInterfaces.h"
 
-namespace mlir {
 namespace test {
 
 /// FieldInfo represents a field in the StructType data type. It is used as a
 /// parameter in TestTypeDefs.td.
 struct FieldInfo {
-  StringRef name;
-  Type type;
+  ::llvm::StringRef name;
+  ::mlir::Type type;
 
   // Custom allocation called from generated constructor code
-  FieldInfo allocateInto(TypeStorageAllocator &alloc) const {
+  FieldInfo allocateInto(::mlir::TypeStorageAllocator &alloc) const {
     return FieldInfo{alloc.copyInto(name), type};
   }
 };
 
 } // namespace test
-} // namespace mlir
 
 #include "TestTypeInterfaces.h.inc"
 
 #define GET_TYPEDEF_CLASSES
 #include "TestTypeDefs.h.inc"
 
-namespace mlir {
 namespace test {
 
 /// Storage for simple named recursive types, where the type is identified by
 /// its name and can "contain" another type, including itself.
-struct TestRecursiveTypeStorage : public TypeStorage {
-  using KeyTy = StringRef;
+struct TestRecursiveTypeStorage : public ::mlir::TypeStorage {
+  using KeyTy = ::llvm::StringRef;
 
-  explicit TestRecursiveTypeStorage(StringRef key) : name(key), body(Type()) {}
+  explicit TestRecursiveTypeStorage(::llvm::StringRef key) : name(key), body(::mlir::Type()) {}
 
   bool operator==(const KeyTy &other) const { return name == other; }
 
-  static TestRecursiveTypeStorage *construct(TypeStorageAllocator &allocator,
+  static TestRecursiveTypeStorage *construct(::mlir::TypeStorageAllocator &allocator,
                                              const KeyTy &key) {
     return new (allocator.allocate<TestRecursiveTypeStorage>())
         TestRecursiveTypeStorage(allocator.copyInto(key));
   }
 
-  LogicalResult mutate(TypeStorageAllocator &allocator, Type newBody) {
+  ::mlir::LogicalResult mutate(::mlir::TypeStorageAllocator &allocator, ::mlir::Type newBody) {
     // Cannot set a different body than before.
     if (body && body != newBody)
-      return failure();
+      return ::mlir::failure();
 
     body = newBody;
-    return success();
+    return ::mlir::success();
   }
 
-  StringRef name;
-  Type body;
+  ::llvm::StringRef name;
+  ::mlir::Type body;
 };
 
 /// Simple recursive type identified by its name and pointing to another named
 /// type, potentially itself. This requires the body to be mutated separately
 /// from type creation.
 class TestRecursiveType
-    : public Type::TypeBase<TestRecursiveType, Type, TestRecursiveTypeStorage> {
+    : public ::mlir::Type::TypeBase<TestRecursiveType, ::mlir::Type, TestRecursiveTypeStorage> {
 public:
   using Base::Base;
 
-  static TestRecursiveType get(MLIRContext *ctx, StringRef name) {
+  static TestRecursiveType get(::mlir::MLIRContext *ctx, ::llvm::StringRef name) {
     return Base::get(ctx, name);
   }
 
   /// Body getter and setter.
-  LogicalResult setBody(Type body) { return Base::mutate(body); }
-  Type getBody() { return getImpl()->body; }
+  ::mlir::LogicalResult setBody(Type body) { return Base::mutate(body); }
+  ::mlir::Type getBody() { return getImpl()->body; }
 
   /// Name/key getter.
-  StringRef getName() { return getImpl()->name; }
+  ::llvm::StringRef getName() { return getImpl()->name; }
 };
 
 } // namespace test
-} // namespace mlir
 
 #endif // MLIR_TESTTYPES_H
diff --git a/mlir/test/lib/Dialect/Test/TestTypes.cpp b/mlir/test/lib/Dialect/Test/TestTypes.cpp
--- a/mlir/test/lib/Dialect/Test/TestTypes.cpp
+++ b/mlir/test/lib/Dialect/Test/TestTypes.cpp
@@ -22,7 +22,7 @@
 #include "llvm/ADT/TypeSwitch.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 // Custom parser for SignednessSemantics.
 static ParseResult
@@ -65,7 +65,6 @@
 // The functions don't need to be in the header file, but need to be in the mlir
 // namespace. Declare them here, then define them immediately below. Separating
 // the declaration and definition adheres to the LLVM coding standards.
-namespace mlir {
 namespace test {
 // FieldInfo is used as part of a parameter, so equality comparison is
 // compulsory.
@@ -73,16 +72,15 @@
 // FieldInfo is used as part of a parameter, so a hash will be computed.
 static llvm::hash_code hash_value(const FieldInfo &fi); // NOLINT
 } // namespace test
-} // namespace mlir
 
 // FieldInfo is used as part of a parameter, so equality comparison is
 // compulsory.
-static bool mlir::test::operator==(const FieldInfo &a, const FieldInfo &b) {
+static bool test::operator==(const FieldInfo &a, const FieldInfo &b) {
   return a.name == b.name && a.type == b.type;
 }
 
 // FieldInfo is used as part of a parameter, so a hash will be computed.
-static llvm::hash_code mlir::test::hash_value(const FieldInfo &fi) { // NOLINT
+static llvm::hash_code test::hash_value(const FieldInfo &fi) { // NOLINT
   return llvm::hash_combine(fi.name, fi.type);
 }
 
diff --git a/mlir/test/lib/IR/TestInterfaces.cpp b/mlir/test/lib/IR/TestInterfaces.cpp
--- a/mlir/test/lib/IR/TestInterfaces.cpp
+++ b/mlir/test/lib/IR/TestInterfaces.cpp
@@ -10,7 +10,7 @@
 #include "mlir/Pass/Pass.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 namespace {
 /// This test checks various aspects of Type interface generation and
diff --git a/mlir/test/lib/IR/TestTypes.cpp b/mlir/test/lib/IR/TestTypes.cpp
--- a/mlir/test/lib/IR/TestTypes.cpp
+++ b/mlir/test/lib/IR/TestTypes.cpp
@@ -11,7 +11,7 @@
 #include "mlir/Pass/Pass.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 namespace {
 struct TestRecursiveTypesPass
diff --git a/mlir/test/lib/Transforms/TestInlining.cpp b/mlir/test/lib/Transforms/TestInlining.cpp
--- a/mlir/test/lib/Transforms/TestInlining.cpp
+++ b/mlir/test/lib/Transforms/TestInlining.cpp
@@ -22,7 +22,7 @@
 #include "llvm/ADT/StringSet.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 namespace {
 struct Inliner : public PassWrapper<Inliner, FunctionPass> {
diff --git a/mlir/test/mlir-tblgen/attrdefs.td b/mlir/test/mlir-tblgen/attrdefs.td
--- a/mlir/test/mlir-tblgen/attrdefs.td
+++ b/mlir/test/mlir-tblgen/attrdefs.td
@@ -13,21 +13,21 @@
 
 // DEF: #ifdef GET_ATTRDEF_LIST
 // DEF: #undef GET_ATTRDEF_LIST
-// DEF: ::mlir::test::SimpleAAttr,
-// DEF: ::mlir::test::CompoundAAttr,
-// DEF: ::mlir::test::IndexAttr,
-// DEF: ::mlir::test::SingleParameterAttr
+// DEF: ::test::SimpleAAttr,
+// DEF: ::test::CompoundAAttr,
+// DEF: ::test::IndexAttr,
+// DEF: ::test::SingleParameterAttr
 
 // DEF-LABEL: ::mlir::OptionalParseResult generatedAttributeParser(::mlir::MLIRContext *context,
 // DEF-NEXT: ::mlir::DialectAsmParser &parser,
 // DEF-NEXT: ::llvm::StringRef mnemonic, ::mlir::Type type,
 // DEF-NEXT: ::mlir::Attribute &value) {
-// DEF: if (mnemonic == ::mlir::test::CompoundAAttr::getMnemonic()) {
-// DEF-NEXT: value = ::mlir::test::CompoundAAttr::parse(context, parser, type);
+// DEF: if (mnemonic == ::test::CompoundAAttr::getMnemonic()) {
+// DEF-NEXT: value = ::test::CompoundAAttr::parse(context, parser, type);
 // DEF-NEXT: return ::mlir::success(!!value);
 // DEF-NEXT: }
-// DEF-NEXT: if (mnemonic == ::mlir::test::IndexAttr::getMnemonic()) {
-// DEF-NEXT:   value = ::mlir::test::IndexAttr::parse(context, parser, type);
+// DEF-NEXT: if (mnemonic == ::test::IndexAttr::getMnemonic()) {
+// DEF-NEXT:   value = ::test::IndexAttr::parse(context, parser, type);
 // DEF-NEXT:   return ::mlir::success(!!value);
 // DEF: return {};
 
@@ -35,7 +35,7 @@
 // DECL-NOT: TestDialect
 // DEF-NOT: TestDialect
     let name = "TestDialect";
-    let cppNamespace = "::mlir::test";
+    let cppNamespace = "::test";
 }
 
 class TestAttr<string name> : AttrDef<Test_Dialect, name> { }
@@ -52,7 +52,7 @@
   let parameters = (
       ins
       "int":$widthOfSomething,
-      "::mlir::test::SimpleTypeA": $exampleTdType,
+      "::test::SimpleTypeA": $exampleTdType,
       APFloatParameter<"">: $apFloat,
       ArrayRefParameter<"int", "Matrix dimensions">:$dims,
       AttributeSelfTypeParameter<"">:$inner
@@ -61,8 +61,8 @@
   let genVerifyDecl = 1;
 
 // DECL-LABEL: class CompoundAAttr : public ::mlir::Attribute
-// DECL: static CompoundAAttr getChecked(llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::mlir::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
-// DECL: static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, int widthOfSomething, ::mlir::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
+// DECL: static CompoundAAttr getChecked(llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
+// DECL: static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, int widthOfSomething, ::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
 // DECL: static constexpr ::llvm::StringLiteral getMnemonic() {
 // DECL:   return ::llvm::StringLiteral("cmpnd_a");
 // DECL: }
@@ -70,7 +70,7 @@
 // DECL-NEXT: ::mlir::DialectAsmParser &parser, ::mlir::Type type);
 // DECL: void print(::mlir::DialectAsmPrinter &printer) const;
 // DECL: int getWidthOfSomething() const;
-// DECL: ::mlir::test::SimpleTypeA getExampleTdType() const;
+// DECL: ::test::SimpleTypeA getExampleTdType() const;
 // DECL: ::llvm::APFloat getApFloat() const;
 
 // Check that AttributeSelfTypeParameter is handled properly.
diff --git a/mlir/test/mlir-tblgen/typedefs.td b/mlir/test/mlir-tblgen/typedefs.td
--- a/mlir/test/mlir-tblgen/typedefs.td
+++ b/mlir/test/mlir-tblgen/typedefs.td
@@ -13,22 +13,22 @@
 
 // DEF: #ifdef GET_TYPEDEF_LIST
 // DEF: #undef GET_TYPEDEF_LIST
-// DEF: ::mlir::test::SimpleAType,
-// DEF: ::mlir::test::CompoundAType,
-// DEF: ::mlir::test::IndexType,
-// DEF: ::mlir::test::SingleParameterType,
-// DEF: ::mlir::test::IntegerType
+// DEF: ::test::SimpleAType,
+// DEF: ::test::CompoundAType,
+// DEF: ::test::IndexType,
+// DEF: ::test::SingleParameterType,
+// DEF: ::test::IntegerType
 
 // DEF-LABEL: ::mlir::OptionalParseResult generatedTypeParser(::mlir::MLIRContext *context,
 // DEF-NEXT: ::mlir::DialectAsmParser &parser,
 // DEF-NEXT: ::llvm::StringRef mnemonic,
 // DEF-NEXT: ::mlir::Type &value) {
-// DEF: if (mnemonic == ::mlir::test::CompoundAType::getMnemonic()) {
-// DEF-NEXT:   value = ::mlir::test::CompoundAType::parse(context, parser);
+// DEF: if (mnemonic == ::test::CompoundAType::getMnemonic()) {
+// DEF-NEXT:   value = ::test::CompoundAType::parse(context, parser);
 // DEF-NEXT:   return ::mlir::success(!!value);
 // DEF-NEXT: }
-// DEF-NEXT: if (mnemonic == ::mlir::test::IndexType::getMnemonic()) {
-// DEF-NEXT:   value = ::mlir::test::IndexType::parse(context, parser);
+// DEF-NEXT: if (mnemonic == ::test::IndexType::getMnemonic()) {
+// DEF-NEXT:   value = ::test::IndexType::parse(context, parser);
 // DEF-NEXT:   return ::mlir::success(!!value);
 // DEF: return {};
 
@@ -36,7 +36,7 @@
 // DECL-NOT: TestDialect
 // DEF-NOT: TestDialect
     let name = "TestDialect";
-    let cppNamespace = "::mlir::test";
+    let cppNamespace = "::test";
 }
 
 class TestType<string name> : TypeDef<Test_Dialect, name> { }
@@ -57,7 +57,7 @@
   let parameters = (
       ins
       "int":$widthOfSomething,
-      "::mlir::test::SimpleTypeA": $exampleTdType,
+      "::test::SimpleTypeA": $exampleTdType,
       "SomeCppStruct": $exampleCppType,
       ArrayRefParameter<"int", "Matrix dimensions">:$dims,
       RTLValueType:$inner
@@ -66,8 +66,8 @@
   let genVerifyDecl = 1;
 
 // DECL-LABEL: class CompoundAType : public ::mlir::Type
-// DECL: static CompoundAType getChecked(llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::mlir::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
-// DECL: static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, int widthOfSomething, ::mlir::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
+// DECL: static CompoundAType getChecked(llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
+// DECL: static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, int widthOfSomething, ::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
 // DECL: static constexpr ::llvm::StringLiteral getMnemonic() {
 // DECL:   return ::llvm::StringLiteral("cmpnd_a");
 // DECL: }
@@ -75,7 +75,7 @@
 // DECL-NEXT: ::mlir::DialectAsmParser &parser);
 // DECL: void print(::mlir::DialectAsmPrinter &printer) const;
 // DECL: int getWidthOfSomething() const;
-// DECL: ::mlir::test::SimpleTypeA getExampleTdType() const;
+// DECL: ::test::SimpleTypeA getExampleTdType() const;
 // DECL: SomeCppStruct getExampleCppType() const;
 }
 
diff --git a/mlir/tools/mlir-opt/mlir-opt.cpp b/mlir/tools/mlir-opt/mlir-opt.cpp
--- a/mlir/tools/mlir-opt/mlir-opt.cpp
+++ b/mlir/tools/mlir-opt/mlir-opt.cpp
@@ -70,7 +70,6 @@
 void registerTestDataLayoutQuery();
 void registerTestDecomposeCallGraphTypes();
 void registerTestDiagnosticsPass();
-void registerTestDialect(DialectRegistry &);
 void registerTestDominancePass();
 void registerTestDynamicPipelinePass();
 void registerTestExpandTanhPass();
@@ -108,6 +107,10 @@
 } // namespace test
 } // namespace mlir
 
+namespace test {
+void registerTestDialect(DialectRegistry &);
+} // namespace test
+
 #ifdef MLIR_INCLUDE_TESTS
 void registerTestPasses() {
   registerConvertToTargetEnvPass();
@@ -135,58 +138,58 @@
   registerVectorizerTestPass();
   registerTosaTestQuantUtilAPIPass();
 
-  test::registerConvertCallOpPass();
-  test::registerInliner();
-  test::registerMemRefBoundCheck();
-  test::registerPatternsTestPass();
-  test::registerSimpleParametricTilingPass();
-  test::registerTestAffineLoopParametricTilingPass();
-  test::registerTestAliasAnalysisPass();
-  test::registerTestCallGraphPass();
-  test::registerTestConstantFold();
-  test::registerTestDiagnosticsPass();
+  mlir::test::registerConvertCallOpPass();
+  mlir::test::registerInliner();
+  mlir::test::registerMemRefBoundCheck();
+  mlir::test::registerPatternsTestPass();
+  mlir::test::registerSimpleParametricTilingPass();
+  mlir::test::registerTestAffineLoopParametricTilingPass();
+  mlir::test::registerTestAliasAnalysisPass();
+  mlir::test::registerTestCallGraphPass();
+  mlir::test::registerTestConstantFold();
+  mlir::test::registerTestDiagnosticsPass();
 #if MLIR_CUDA_CONVERSIONS_ENABLED
-  test::registerTestGpuSerializeToCubinPass();
+  mlir::test::registerTestGpuSerializeToCubinPass();
 #endif
 #if MLIR_ROCM_CONVERSIONS_ENABLED
-  test::registerTestGpuSerializeToHsacoPass();
+  mlir::test::registerTestGpuSerializeToHsacoPass();
 #endif
-  test::registerTestConvVectorization();
-  test::registerTestDecomposeCallGraphTypes();
-  test::registerTestDataLayoutQuery();
-  test::registerTestDominancePass();
-  test::registerTestDynamicPipelinePass();
-  test::registerTestExpandTanhPass();
-  test::registerTestComposeSubView();
-  test::registerTestGpuParallelLoopMappingPass();
-  test::registerTestIRVisitorsPass();
-  test::registerTestInterfaces();
-  test::registerTestLinalgCodegenStrategy();
-  test::registerTestLinalgDistribution();
-  test::registerTestLinalgElementwiseFusion();
-  test::registerTestPushExpandingReshape();
-  test::registerTestLinalgFusionTransforms();
-  test::registerTestLinalgTensorFusionTransforms();
-  test::registerTestLinalgTiledLoopFusionTransforms();
-  test::registerTestLinalgGreedyFusion();
-  test::registerTestLinalgHoisting();
-  test::registerTestLinalgTileAndFuseSequencePass();
-  test::registerTestLinalgTransforms();
-  test::registerTestLivenessPass();
-  test::registerTestLoopFusion();
-  test::registerTestLoopMappingPass();
-  test::registerTestLoopUnrollingPass();
-  test::registerTestMathAlgebraicSimplificationPass();
-  test::registerTestMathPolynomialApproximationPass();
-  test::registerTestMemRefDependenceCheck();
-  test::registerTestMemRefStrideCalculation();
-  test::registerTestNumberOfBlockExecutionsPass();
-  test::registerTestNumberOfOperationExecutionsPass();
-  test::registerTestOpaqueLoc();
-  test::registerTestPDLByteCodePass();
-  test::registerTestRecursiveTypesPass();
-  test::registerTestSCFUtilsPass();
-  test::registerTestVectorConversions();
+  mlir::test::registerTestConvVectorization();
+  mlir::test::registerTestDecomposeCallGraphTypes();
+  mlir::test::registerTestDataLayoutQuery();
+  mlir::test::registerTestDominancePass();
+  mlir::test::registerTestDynamicPipelinePass();
+  mlir::test::registerTestExpandTanhPass();
+  mlir::test::registerTestComposeSubView();
+  mlir::test::registerTestGpuParallelLoopMappingPass();
+  mlir::test::registerTestIRVisitorsPass();
+  mlir::test::registerTestInterfaces();
+  mlir::test::registerTestLinalgCodegenStrategy();
+  mlir::test::registerTestLinalgDistribution();
+  mlir::test::registerTestLinalgElementwiseFusion();
+  mlir::test::registerTestPushExpandingReshape();
+  mlir::test::registerTestLinalgFusionTransforms();
+  mlir::test::registerTestLinalgTensorFusionTransforms();
+  mlir::test::registerTestLinalgTiledLoopFusionTransforms();
+  mlir::test::registerTestLinalgGreedyFusion();
+  mlir::test::registerTestLinalgHoisting();
+  mlir::test::registerTestLinalgTileAndFuseSequencePass();
+  mlir::test::registerTestLinalgTransforms();
+  mlir::test::registerTestLivenessPass();
+  mlir::test::registerTestLoopFusion();
+  mlir::test::registerTestLoopMappingPass();
+  mlir::test::registerTestLoopUnrollingPass();
+  mlir::test::registerTestMathAlgebraicSimplificationPass();
+  mlir::test::registerTestMathPolynomialApproximationPass();
+  mlir::test::registerTestMemRefDependenceCheck();
+  mlir::test::registerTestMemRefStrideCalculation();
+  mlir::test::registerTestNumberOfBlockExecutionsPass();
+  mlir::test::registerTestNumberOfOperationExecutionsPass();
+  mlir::test::registerTestOpaqueLoc();
+  mlir::test::registerTestPDLByteCodePass();
+  mlir::test::registerTestRecursiveTypesPass();
+  mlir::test::registerTestSCFUtilsPass();
+  mlir::test::registerTestVectorConversions();
 }
 #endif
 
@@ -198,7 +201,7 @@
   DialectRegistry registry;
   registerAllDialects(registry);
 #ifdef MLIR_INCLUDE_TESTS
-  test::registerTestDialect(registry);
+  ::test::registerTestDialect(registry);
 #endif
   return mlir::asMainReturnCode(
       mlir::MlirOptMain(argc, argv, "MLIR modular optimizer driver\n", registry,
diff --git a/mlir/tools/mlir-reduce/mlir-reduce.cpp b/mlir/tools/mlir-reduce/mlir-reduce.cpp
--- a/mlir/tools/mlir-reduce/mlir-reduce.cpp
+++ b/mlir/tools/mlir-reduce/mlir-reduce.cpp
@@ -21,13 +21,11 @@
 
 using namespace mlir;
 
-namespace mlir {
 namespace test {
 #ifdef MLIR_INCLUDE_TESTS
 void registerTestDialect(DialectRegistry &);
 #endif
 } // namespace test
-} // namespace mlir
 
 int main(int argc, char **argv) {
   registerAllPasses();
diff --git a/mlir/unittests/IR/InterfaceAttachmentTest.cpp b/mlir/unittests/IR/InterfaceAttachmentTest.cpp
--- a/mlir/unittests/IR/InterfaceAttachmentTest.cpp
+++ b/mlir/unittests/IR/InterfaceAttachmentTest.cpp
@@ -22,7 +22,7 @@
 #include "../../test/lib/Dialect/Test/TestTypes.h"
 
 using namespace mlir;
-using namespace mlir::test;
+using namespace test;
 
 namespace {