Shadow lambda arguments

In case of ambiguity, lambda functions should prefer its arguments to
other aliases or identifiers

src/Interpreters/QueryNormalizer.cpp

@@ -3,6 +3,7 @@
 #include <Interpreters/QueryNormalizer.h>
 #include <Interpreters/IdentifierSemantic.h>
 #include <Interpreters/Context.h>
+#include <Interpreters/RequiredSourceColumnsVisitor.h>
 #include <Parsers/ASTFunction.h>
 #include <Parsers/ASTIdentifier.h>
 #include <Parsers/ASTSelectQuery.h>
@@ -170,6 +171,24 @@ void QueryNormalizer::visitChildren(IAST * node, Data & data)
             /// Don't go into query argument.
             return;
         }
+
+        /// For lambda functions we need to avoid replacing lambda parameters with external aliases, for example,
+        /// Select 1 as x, arrayMap(x -> x + 2, [1, 2, 3])
+        /// shouldn't be replaced with Select 1 as x, arrayMap(x -> **(1 as x)** + 2, [1, 2, 3])
+        Aliases extracted_aliases;
+        if (func_node->name == "lambda")
+        {
+            Names lambda_aliases = RequiredSourceColumnsMatcher::extractNamesFromLambda(*func_node);
+            for (const auto & name : lambda_aliases)
+            {
+                auto it = data.aliases.find(name);
+                if (it != data.aliases.end())
+                {
+                    extracted_aliases.insert(data.aliases.extract(it));
+                }
+            }
+        }
+
         /// We skip the first argument. We also assume that the lambda function can not have parameters.
         size_t first_pos = 0;
         if (func_node->name == "lambda")
@@ -192,6 +211,11 @@ void QueryNormalizer::visitChildren(IAST * node, Data & data)
         {
             visitChildren(func_node->window_definition.get(), data);
         }
+
+        for (auto & it : extracted_aliases)
+        {
+            data.aliases.insert(it);
+        }
     }
     else if (!node->as<ASTSelectQuery>())
     {

src/Interpreters/QueryNormalizer.h

@@ -39,7 +39,7 @@ public:
         using SetOfASTs = std::set<const IAST *>;
         using MapOfASTs = std::map<ASTPtr, ASTPtr>;
 
-        const Aliases & aliases;
+        Aliases & aliases;
         const NameSet & source_columns_set;
         ExtractedSettings settings;
 
@@ -53,7 +53,7 @@ public:
         /// It's Ok to have "c + 1 AS c" in queries, but not in table definition
         const bool allow_self_aliases; /// for constructs like "SELECT column + 1 AS column"
 
-        Data(const Aliases & aliases_, const NameSet & source_columns_set_, bool ignore_alias_, ExtractedSettings && settings_, bool allow_self_aliases_)
+        Data(Aliases & aliases_, const NameSet & source_columns_set_, bool ignore_alias_, ExtractedSettings && settings_, bool allow_self_aliases_)
             : aliases(aliases_)
             , source_columns_set(source_columns_set_)
             , settings(settings_)

tests/queries/0_stateless/01960_lambda_precedence.reference

@@ -0,0 +1,3 @@
+1000	[2,3,4]
+1
+1

tests/queries/0_stateless/01960_lambda_precedence.sql

@@ -0,0 +1,25 @@
+SELECT
+    1000 AS a,
+    arrayMap(a -> (a + 1), [1, 2, 3]);
+
+
+-- https://github.com/ClickHouse/ClickHouse/issues/5046
+SELECT sum(c1) AS v
+FROM
+    (
+     SELECT
+         1 AS c1,
+         ['v'] AS c2
+        )
+WHERE arrayExists(v -> (v = 'v'), c2);
+
+
+SELECT sum(c1) AS v
+FROM
+    (
+     SELECT
+         1 AS c1,
+         ['v'] AS c2,
+         ['d'] AS d
+        )
+WHERE arrayExists(i -> (d = ['d']), c2);