Fix DUMP debug.

dbms/src/Core/iostream_debug_helpers.cpp

@@ -18,15 +18,17 @@
 
 namespace DB
 {
-std::ostream & operator<<(std::ostream & stream, const IBlockInputStream & what)
+
+template <>
+std::ostream & operator<< <Field>(std::ostream & stream, const Field & what)
 {
-    stream << "IBlockInputStream(name = " << what.getName() << ")";
+    stream << applyVisitor(FieldVisitorDump(), what);
     return stream;
 }
 
-std::ostream & operator<<(std::ostream & stream, const Field & what)
+std::ostream & operator<<(std::ostream & stream, const IBlockInputStream & what)
 {
-    stream << applyVisitor(FieldVisitorDump(), what);
+    stream << "IBlockInputStream(name = " << what.getName() << ")";
     return stream;
 }
 
@@ -102,14 +104,6 @@ std::ostream & operator<<(std::ostream & stream, const Connection::Packet & what
     return stream;
 }
 
-std::ostream & operator<<(std::ostream & stream, const IAST & what)
-{
-    stream << "IAST{";
-    what.dumpTree(stream);
-    stream << "}";
-    return stream;
-}
-
 std::ostream & operator<<(std::ostream & stream, const ExpressionAction & what)
 {
     stream << "ExpressionAction(" << what.toString() << ")";

dbms/src/Core/iostream_debug_helpers.h

@@ -7,18 +7,15 @@
 namespace DB
 {
 
-// Used to disable implicit casting for certain overloaded types such as Field, which leads to
-// overload resolution ambiguity.
-template <typename T> struct Dumpable;
-template <typename T>
-std::ostream & operator<<(std::ostream & stream, const typename Dumpable<T>::Type & what);
+// Use template to disable implicit casting for certain overloaded types such as Field, which leads
+// to overload resolution ambiguity.
+class Field;
+template <typename T, typename U = std::enable_if_t<std::is_same_v<T, Field>>>
+std::ostream & operator<<(std::ostream & stream, const T & what);
 
 class IBlockInputStream;
 std::ostream & operator<<(std::ostream & stream, const IBlockInputStream & what);
 
-class Field;
-template <> struct Dumpable<Field> { using Type = Field; };
-
 struct NameAndTypePair;
 std::ostream & operator<<(std::ostream & stream, const NameAndTypePair & what);
 
@@ -43,9 +40,6 @@ std::ostream & operator<<(std::ostream & stream, const ColumnWithTypeAndName & w
 class IColumn;
 std::ostream & operator<<(std::ostream & stream, const IColumn & what);
 
-class IAST;
-std::ostream & operator<<(std::ostream & stream, const IAST & what);
-
 std::ostream & operator<<(std::ostream & stream, const Connection::Packet & what);
 
 struct ExpressionAction;

dbms/src/Parsers/iostream_debug_helpers.cpp

@@ -1,4 +1,5 @@
 #include "iostream_debug_helpers.h"
+#include <Parsers/IAST.h>
 #include <Parsers/IParser.h>
 #include <Parsers/Lexer.h>
 #include <Parsers/TokenIterator.h>
@@ -20,4 +21,12 @@ std::ostream & operator<<(std::ostream & stream, const Expected & what)
     return stream;
 }
 
+std::ostream & operator<<(std::ostream & stream, const IAST & what)
+{
+    stream << "IAST{";
+    what.dumpTree(stream);
+    stream << "}";
+    return stream;
+}
+
 }

dbms/src/Parsers/iostream_debug_helpers.h

@@ -9,6 +9,9 @@ std::ostream & operator<<(std::ostream & stream, const Token & what);
 struct Expected;
 std::ostream & operator<<(std::ostream & stream, const Expected & what);
 
+class IAST;
+std::ostream & operator<<(std::ostream & stream, const IAST & what);
+
 }
 
 #include <Core/iostream_debug_helpers.h>