diff --git a/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/parser/GroovyGeneratedParser.java b/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/parser/GroovyGeneratedParser.java
index 47e432f781c9..36037d231020 100644
--- a/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/parser/GroovyGeneratedParser.java
+++ b/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/parser/GroovyGeneratedParser.java
@@ -269,12 +269,12 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
       BAND_EXPRESSION, BOR_EXPRESSION, BUILT_IN_TYPE_EXPRESSION, CAST_EXPRESSION,
       CLOSURE, CONSTRUCTOR_CALL_EXPRESSION, ELVIS_EXPRESSION, EQUALITY_EXPRESSION,
       EXPRESSION, GSTRING, INDEX_EXPRESSION, INSTANCEOF_EXPRESSION,
-      LAND_EXPRESSION, LIST_OR_MAP, LITERAL, LOR_EXPRESSION,
-      METHOD_CALL_EXPRESSION, MULTIPLICATIVE_EXPRESSION, NEW_EXPRESSION, PARENTHESIZED_EXPRESSION,
-      POWER_EXPRESSION, PROPERTY_EXPRESSION, RANGE_EXPRESSION, REFERENCE_EXPRESSION,
-      REGEX, REGEX_FIND_EXPRESSION, REGEX_MATCH_EXPRESSION, RELATIONAL_EXPRESSION,
-      SHIFT_EXPRESSION, TERNARY_EXPRESSION, TUPLE_ASSIGNMENT_EXPRESSION, UNARY_EXPRESSION,
-      XOR_EXPRESSION),
+      IN_EXPRESSION, LAND_EXPRESSION, LIST_OR_MAP, LITERAL,
+      LOR_EXPRESSION, METHOD_CALL_EXPRESSION, MULTIPLICATIVE_EXPRESSION, NEW_EXPRESSION,
+      PARENTHESIZED_EXPRESSION, POWER_EXPRESSION, PROPERTY_EXPRESSION, RANGE_EXPRESSION,
+      REFERENCE_EXPRESSION, REGEX, REGEX_FIND_EXPRESSION, REGEX_MATCH_EXPRESSION,
+      RELATIONAL_EXPRESSION, SHIFT_EXPRESSION, TERNARY_EXPRESSION, TUPLE_ASSIGNMENT_EXPRESSION,
+      UNARY_EXPRESSION, XOR_EXPRESSION),
   };
 
   /* ********************************************************** */
@@ -3758,6 +3758,40 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
     return r;
   }
 
+  /* ********************************************************** */
+  // mb_not ('instanceof') (type_element | expect_type)
+  static boolean instanceof_expression_tail(PsiBuilder b, int l) {
+    if (!recursion_guard_(b, l, "instanceof_expression_tail")) return false;
+    if (!nextTokenIsFast(b, T_NOT, KW_INSTANCEOF)) return false;
+    boolean r, p;
+    Marker m = enter_section_(b, l, _NONE_);
+    r = mb_not(b, l + 1);
+    r = r && instanceof_expression_tail_1(b, l + 1);
+    p = r; // pin = 2
+    r = r && instanceof_expression_tail_2(b, l + 1);
+    exit_section_(b, l, m, r, p, null);
+    return r || p;
+  }
+
+  // ('instanceof')
+  private static boolean instanceof_expression_tail_1(PsiBuilder b, int l) {
+    if (!recursion_guard_(b, l, "instanceof_expression_tail_1")) return false;
+    boolean r;
+    Marker m = enter_section_(b);
+    r = consumeTokenFast(b, KW_INSTANCEOF);
+    exit_section_(b, m, null, r);
+    return r;
+  }
+
+  // type_element | expect_type
+  private static boolean instanceof_expression_tail_2(PsiBuilder b, int l) {
+    if (!recursion_guard_(b, l, "instanceof_expression_tail_2")) return false;
+    boolean r;
+    r = type_element(b, l + 1);
+    if (!r) r = expect_type(b, l + 1);
+    return r;
+  }
+
   /* ********************************************************** */
   // <<classIdentifier>> type_parameter_list? nl_extends nl_non_empty_implements?
   static boolean interface_definition_header(PsiBuilder b, int l) {
@@ -3940,6 +3974,14 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
     return r;
   }
 
+  /* ********************************************************** */
+  // '!'?
+  static boolean mb_not(PsiBuilder b, int l) {
+    if (!recursion_guard_(b, l, "mb_not")) return false;
+    consumeTokenFast(b, T_NOT);
+    return true;
+  }
+
   /* ********************************************************** */
   // '?'?
   static boolean mb_question(PsiBuilder b, int l) {
@@ -5097,7 +5139,7 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
   }
 
   /* ********************************************************** */
-  // '<' !'<' | '<=' | '>' !'>' | '>=' | 'in'
+  // '<' !'<' | '<=' | '>' !'>' | '>='
   static boolean relational_operator(PsiBuilder b, int l) {
     if (!recursion_guard_(b, l, "relational_operator")) return false;
     boolean r;
@@ -5106,7 +5148,6 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
     if (!r) r = consumeTokenFast(b, T_LE);
     if (!r) r = relational_operator_2(b, l + 1);
     if (!r) r = consumeTokenFast(b, T_GE);
-    if (!r) r = consumeTokenFast(b, KW_IN);
     exit_section_(b, m, null, r);
     return r;
   }
@@ -6592,7 +6633,7 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
   // 5: BINARY(xor_expression)
   // 6: BINARY(band_expression)
   // 7: BINARY(equality_expression) BINARY(compare_expression) BINARY(regex_find_expression) BINARY(regex_match_expression)
-  // 8: BINARY(relational_expression) POSTFIX(instanceof_expression) POSTFIX(as_expression)
+  // 8: BINARY(relational_expression) BINARY(in_expression) POSTFIX(instanceof_expression) POSTFIX(as_expression)
   // 9: BINARY(shift_expression) BINARY(range_expression)
   // 10: BINARY(additive_expression)
   // 11: BINARY(multiplicative_expression)
@@ -6688,7 +6729,11 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
         r = expression(b, l, 8);
         exit_section_(b, l, m, RELATIONAL_EXPRESSION, r, true, null);
       }
-      else if (g < 8 && instanceof_expression_0(b, l + 1)) {
+      else if (g < 8 && in_expression_0(b, l + 1)) {
+        r = expression(b, l, 8);
+        exit_section_(b, l, m, IN_EXPRESSION, r, true, null);
+      }
+      else if (g < 8 && instanceof_expression_tail(b, l + 1)) {
         r = true;
         exit_section_(b, l, m, INSTANCEOF_EXPRESSION, r, true, null);
       }
@@ -6842,24 +6887,24 @@ public class GroovyGeneratedParser implements PsiParser, LightPsiParser {
     return r;
   }
 
-  // 'instanceof' (type_element | expect_type)
-  private static boolean instanceof_expression_0(PsiBuilder b, int l) {
-    if (!recursion_guard_(b, l, "instanceof_expression_0")) return false;
-    boolean r, p;
-    Marker m = enter_section_(b, l, _NONE_);
-    r = consumeTokenSmart(b, KW_INSTANCEOF);
-    p = r; // pin = 1
-    r = r && instanceof_expression_0_1(b, l + 1);
-    exit_section_(b, l, m, r, p, null);
-    return r || p;
+  // mb_not ('in')
+  private static boolean in_expression_0(PsiBuilder b, int l) {
+    if (!recursion_guard_(b, l, "in_expression_0")) return false;
+    boolean r;
+    Marker m = enter_section_(b);
+    r = mb_not(b, l + 1);
+    r = r && in_expression_0_1(b, l + 1);
+    exit_section_(b, m, null, r);
+    return r;
   }
 
-  // type_element | expect_type
-  private static boolean instanceof_expression_0_1(PsiBuilder b, int l) {
-    if (!recursion_guard_(b, l, "instanceof_expression_0_1")) return false;
+  // ('in')
+  private static boolean in_expression_0_1(PsiBuilder b, int l) {
+    if (!recursion_guard_(b, l, "in_expression_0_1")) return false;
     boolean r;
-    r = type_element(b, l + 1);
-    if (!r) r = expect_type(b, l + 1);
+    Marker m = enter_section_(b);
+    r = consumeTokenSmart(b, KW_IN);
+    exit_section_(b, m, null, r);
     return r;
   }
 
diff --git a/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/psi/GroovyElementTypes.java b/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/psi/GroovyElementTypes.java
index 0634d5648619..c5b10c44da1b 100644
--- a/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/psi/GroovyElementTypes.java
+++ b/plugins/groovy/groovy-psi/gen/org/jetbrains/plugins/groovy/lang/psi/GroovyElementTypes.java
@@ -102,6 +102,7 @@ public interface GroovyElementTypes {
   GroovyElementType INDEX_EXPRESSION = new GroovyElementType("INDEX_EXPRESSION");
   GroovyElementType INSTANCEOF_EXPRESSION = new GroovyElementType("INSTANCEOF_EXPRESSION");
   GrInterfaceDefinitionElementType INTERFACE_TYPE_DEFINITION = new GrInterfaceDefinitionElementType("INTERFACE_TYPE_DEFINITION");
+  GroovyElementType IN_EXPRESSION = new GroovyElementType("IN_EXPRESSION");
   GroovyElementType LABELED_STATEMENT = new GroovyElementType("LABELED_STATEMENT");
   GroovyElementType LAND_EXPRESSION = new GroovyElementType("LAND_EXPRESSION");
   GroovyElementType LEFT_SHIFT_SIGN = new GroovyElementType("LEFT_SHIFT_SIGN");
diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/GroovyPsiCreator.java b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/GroovyPsiCreator.java
index 737af0f3e109..458db354e1e3 100644
--- a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/GroovyPsiCreator.java
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/GroovyPsiCreator.java
@@ -9,6 +9,7 @@ import org.jetbrains.plugins.groovy.lang.groovydoc.lexer.IGroovyDocElementType;
 import org.jetbrains.plugins.groovy.lang.groovydoc.psi.GroovyDocPsiCreator;
 import org.jetbrains.plugins.groovy.lang.lexer.GroovyElementType;
 import org.jetbrains.plugins.groovy.lang.psi.impl.GrImportAliasImpl;
+import org.jetbrains.plugins.groovy.lang.psi.impl.GrInExpressionImpl;
 import org.jetbrains.plugins.groovy.lang.psi.impl.GroovyASTPsiElementImpl;
 import org.jetbrains.plugins.groovy.lang.psi.impl.auxiliary.GrListOrMapImpl;
 import org.jetbrains.plugins.groovy.lang.psi.impl.auxiliary.GrThrowsClauseImpl;
@@ -182,6 +183,7 @@ public class GroovyPsiCreator {
     if (elem == REGEX_FIND_EXPRESSION) return new GrRegexFindExpressionImpl(node);
     if (elem == EQUALITY_EXPRESSION) return new GrRelationalExpressionImpl(node);
     if (elem == RELATIONAL_EXPRESSION) return new GrRelationalExpressionImpl(node);
+    if (elem == IN_EXPRESSION) return new GrInExpressionImpl(node);
     if (elem == SHIFT_EXPRESSION) return new GrShiftExpressionImpl(node);
     if (elem == RANGE_EXPRESSION) return new GrRangeExpressionImpl(node);
     if (elem == ADDITIVE_EXPRESSION) return new GrAdditiveExpressionImpl(node);
diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/groovy.bnf b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/groovy.bnf
index b5febb927c57..7ed615fbd71e 100644
--- a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/groovy.bnf
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/groovy.bnf
@@ -176,6 +176,7 @@
   elementType('.*_reference_expression') = reference_expression
   elementType('.*_class_type_element') = class_type_element
   consumeTokenMethod('.*_expression') = 'consumeTokenFast'
+  consumeTokenMethod('.*_expression_tail') = 'consumeTokenFast'
   consumeTokenMethod('.*_shift.*_sign') = 'consumeTokenFast'
   consumeTokenMethod('fast.*') = 'consumeTokenFast'
   consumeTokenMethod('.*_type_definition') = 'consumeTokenFast'
@@ -1039,14 +1040,12 @@ right_shift_sign ::= '>' '>'
 right_shift_unsigned_sign ::= '>' '>' '>'
 range_expression ::= expression ('..' | '..<') expression
 
-private priority7 ::= relational_expression | instanceof_expression | as_expression
+private priority7 ::= relational_expression | in_expression | instanceof_expression | as_expression
 relational_expression ::= expression relational_operator mb_nl expression
-private relational_operator ::= '<' !'<' | '<=' | '>' !'>' | '>=' | 'in' { consumeTokenMethod = 'consumeTokenFast' }
-
-instanceof_expression ::= expression ('instanceof' (type_element | expect_type))
-{
-  pin('.*') = 1
-}
+private relational_operator ::= '<' !'<' | '<=' | '>' !'>' | '>=' { consumeTokenMethod = 'consumeTokenFast' }
+in_expression ::= expression mb_not ('in') expression
+instanceof_expression ::= expression instanceof_expression_tail
+private instanceof_expression_tail ::= mb_not ('instanceof') (type_element | expect_type) { pin = 2 }
 as_expression ::= expression 'as' type_element
 
 private priority8 ::= equality_expression | compare_expression | regex_find_expression | regex_match_expression
@@ -1239,6 +1238,7 @@ private meta mb_nl_group ::= <<something>> | <<withProtectedLastVariantPos (nl <
 private empty ::= ()
 
 private mb_question ::= '?'? { consumeTokenMethod = 'consumeTokenFast' }
+private mb_not ::= '!'? { consumeTokenMethod = 'consumeTokenFast' }
 
 private fast_colon ::= ':'
 private fast_comma ::= ','
diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/api/GrInExpression.java b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/api/GrInExpression.java
new file mode 100644
index 000000000000..a1901efe12a7
--- /dev/null
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/api/GrInExpression.java
@@ -0,0 +1,7 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.lang.psi.api;
+
+import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrBinaryExpression;
+
+public interface GrInExpression extends GrBinaryExpression {
+}
diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/GrInExpressionImpl.kt b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/GrInExpressionImpl.kt
new file mode 100644
index 000000000000..7bf6b2370dca
--- /dev/null
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/GrInExpressionImpl.kt
@@ -0,0 +1,11 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.lang.psi.impl
+
+import com.intellij.lang.ASTNode
+import org.jetbrains.plugins.groovy.lang.psi.api.GrInExpression
+import org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrBinaryExpressionImpl
+
+class GrInExpressionImpl(node: ASTNode) : GrBinaryExpressionImpl(node), GrInExpression {
+
+  override fun toString(): String = "${javaClass.simpleName}(${node.elementType})"
+}
diff --git a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/parser/ExpressionsParsingTest.groovy b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/parser/ExpressionsParsingTest.groovy
index 004c72bc9b1f..012c38e3cf69 100644
--- a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/parser/ExpressionsParsingTest.groovy
+++ b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/parser/ExpressionsParsingTest.groovy
@@ -464,6 +464,12 @@ class ExpressionsParsingTest extends GroovyParsingTestCase {
 
   void testrelational$noRValue() { doTest() }
 
+  void testrelational$exclamationAfterExpression() { doTest() }
+
+  void testrelational$inNegated() { doTest() }
+
+  void testrelational$instanceOfNegated() { doTest() }
+
   void testspecial$grvy1173() throws Throwable { doTest() }
 
   void testspecial$list1() throws Throwable { doTest() }
diff --git a/plugins/groovy/testdata/groovy/controlFlow/varInString.test b/plugins/groovy/testdata/groovy/controlFlow/varInString.test
index 0a7fbd8b667f..1cf176071e42 100644
--- a/plugins/groovy/testdata/groovy/controlFlow/varInString.test
+++ b/plugins/groovy/testdata/groovy/controlFlow/varInString.test
@@ -3,9 +3,9 @@ if (i in String) i = i.substring(2)
 0(1) element: null
 1(2) element: IF statement
 2(3) READ i
-3(4,6) Condition Relational expression
+3(4,6) Condition GrInExpressionImpl(IN_EXPRESSION)
 4(5) instanceof: i in String
-5(10)  Negating goto instruction, condition=3Relational expression
+5(10)  Negating goto instruction, condition=3GrInExpressionImpl(IN_EXPRESSION)
 6(7) instanceof: i in String
 7(8) READ i
 8(9) WRITE i
diff --git a/plugins/groovy/testdata/parsing/groovy/expressions/commandExpr/in.test b/plugins/groovy/testdata/parsing/groovy/expressions/commandExpr/in.test
index 9d356a2df9bb..b0a22b02d928 100644
--- a/plugins/groovy/testdata/parsing/groovy/expressions/commandExpr/in.test
+++ b/plugins/groovy/testdata/parsing/groovy/expressions/commandExpr/in.test
@@ -10,7 +10,7 @@ Groovy script
       PsiWhiteSpace(' ')
       PsiElement(=)('=')
       PsiWhiteSpace(' ')
-      Relational expression
+      GrInExpressionImpl(IN_EXPRESSION)
         Method call
           Reference expression
             PsiElement(identifier)('abc')
diff --git a/plugins/groovy/testdata/parsing/groovy/expressions/relational/exclamationAfterExpression.test b/plugins/groovy/testdata/parsing/groovy/expressions/relational/exclamationAfterExpression.test
new file mode 100644
index 000000000000..8f8e2dfccf3d
--- /dev/null
+++ b/plugins/groovy/testdata/parsing/groovy/expressions/relational/exclamationAfterExpression.test
@@ -0,0 +1,12 @@
+a !
+-----
+Groovy script
+  Call expression
+    Reference expression
+      PsiElement(identifier)('a')
+    PsiWhiteSpace(' ')
+    Command arguments
+      Unary expression
+        PsiElement(!)('!')
+        PsiErrorElement:<expression> expected
+          <empty list>
\ No newline at end of file
diff --git a/plugins/groovy/testdata/parsing/groovy/expressions/relational/inNegated.test b/plugins/groovy/testdata/parsing/groovy/expressions/relational/inNegated.test
new file mode 100644
index 000000000000..6f38f5bb0816
--- /dev/null
+++ b/plugins/groovy/testdata/parsing/groovy/expressions/relational/inNegated.test
@@ -0,0 +1,12 @@
+a !in b
+-----
+Groovy script
+  GrInExpressionImpl(IN_EXPRESSION)
+    Reference expression
+      PsiElement(identifier)('a')
+    PsiWhiteSpace(' ')
+    PsiElement(!)('!')
+    PsiElement(in)('in')
+    PsiWhiteSpace(' ')
+    Reference expression
+      PsiElement(identifier)('b')
\ No newline at end of file
diff --git a/plugins/groovy/testdata/parsing/groovy/expressions/relational/instanceOfNegated.test b/plugins/groovy/testdata/parsing/groovy/expressions/relational/instanceOfNegated.test
new file mode 100644
index 000000000000..94b19b6c4f19
--- /dev/null
+++ b/plugins/groovy/testdata/parsing/groovy/expressions/relational/instanceOfNegated.test
@@ -0,0 +1,13 @@
+a !instanceof b
+-----
+Groovy script
+  Instanceof expression
+    Reference expression
+      PsiElement(identifier)('a')
+    PsiWhiteSpace(' ')
+    PsiElement(!)('!')
+    PsiElement(instanceof)('instanceof')
+    PsiWhiteSpace(' ')
+    Type element
+      Reference element
+        PsiElement(identifier)('b')
\ No newline at end of file