diff --git a/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/xform/TypeCheckedTests.java b/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/xform/TypeCheckedTests.java
index 281982c4bc..e15c25ca36 100644
--- a/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/xform/TypeCheckedTests.java
+++ b/base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/xform/TypeCheckedTests.java
@@ -425,9 +425,6 @@ public void testTypeChecked18() {
         //@formatter:off
         String[] sources = {
             "Main.groovy",
-            "class C {\n" +
-            "  boolean b\n" +
-            "}\n" +
             "@groovy.transform.TypeChecked\n" +
             "void test() {\n" +
             "  print(new Pogo().isFlag())\n" +
@@ -481,6 +478,28 @@ public void testTypeChecked19() {
         runConformTest(sources, "test");
     }
 
+    @Test
+    public void testTypeChecked20() {
+        //@formatter:off
+        String[] sources = {
+            "Main.groovy",
+            "def <T> T m(java.util.function.Consumer<? super T> c) {\n" +
+            "  c.accept(null)\n" +
+            "  null\n" +
+            "}\n" +
+            "@groovy.transform.TypeChecked\n" +
+            "void test() {\n" +
+            "  this.<Number>m { n ->\n" +
+            "    n?.toBigInteger()\n" +
+            "  }\n" +
+            "}\n" +
+            "test()\n",
+        };
+        //@formatter:on
+
+        runConformTest(sources);
+    }
+
     @Test
     public void testTypeChecked5450() {
         //@formatter:off
diff --git a/base/org.codehaus.groovy25/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java b/base/org.codehaus.groovy25/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java
index 0f4a81a751..486b324ff1 100644
--- a/base/org.codehaus.groovy25/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java
+++ b/base/org.codehaus.groovy25/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java
@@ -3416,7 +3416,8 @@ protected void silentlyVisitMethodNode(final MethodNode directMethodCallCandidat
         startMethodInference(directMethodCallCandidate, collector);
     }
 
-    protected void visitMethodCallArguments(final ClassNode receiver, ArgumentListExpression arguments, boolean visitClosures, final MethodNode selectedMethod) {
+    protected void visitMethodCallArguments(final ClassNode receiver, final ArgumentListExpression arguments, final boolean visitClosures, final MethodNode selectedMethod) {
+        /* GRECLIPSE edit
         Parameter[] params = selectedMethod != null ? selectedMethod.getParameters() : Parameter.EMPTY_ARRAY;
         List<Expression> expressions = new LinkedList<Expression>(arguments.getExpressions());
         if (selectedMethod instanceof ExtensionMethodNode) {
@@ -3424,20 +3425,31 @@ protected void visitMethodCallArguments(final ClassNode receiver, ArgumentListEx
             expressions.add(0, varX("$self", receiver));
         }
         ArgumentListExpression newArgs = args(expressions);
-
-        for (int i = 0, expressionsSize = expressions.size(); i < expressionsSize; i++) {
+        */
+        Parameter[] params;
+        List<Expression> expressions = new ArrayList<>();
+        if (selectedMethod instanceof ExtensionMethodNode) {
+            params = ((ExtensionMethodNode) selectedMethod).getExtensionMethodNode().getParameters();
+            expressions.add(varX("$self", receiver));
+        } else {
+            params = selectedMethod != null ? selectedMethod.getParameters() : Parameter.EMPTY_ARRAY;
+        }
+        expressions.addAll(arguments.getExpressions());
+        if (expressions.isEmpty()) return;
+        // GRECLIPSE end
+        for (int i = 0, n = expressions.size(); i < n; i++) {
             final Expression expression = expressions.get(i);
             if (visitClosures && expression instanceof ClosureExpression
                     || !visitClosures && !(expression instanceof ClosureExpression)) {
                 if (i < params.length && visitClosures) {
                     Parameter param = params[i];
-                    checkClosureWithDelegatesTo(receiver, selectedMethod, newArgs, params, expression, param);
+                    checkClosureWithDelegatesTo(receiver, selectedMethod, args(expressions), params, expression, param);
                     if (selectedMethod instanceof ExtensionMethodNode) {
                         if (i > 0) {
                             inferClosureParameterTypes(receiver, arguments, (ClosureExpression) expression, param, selectedMethod);
                         }
                     } else {
-                        inferClosureParameterTypes(receiver, newArgs, (ClosureExpression) expression, param, selectedMethod);
+                        inferClosureParameterTypes(receiver, arguments, (ClosureExpression) expression, param, selectedMethod);
                     }
                     // GRECLIPSE add -- GROOVY-9971
                     ClassNode targetType = param.getType();
@@ -3449,12 +3461,10 @@ protected void visitMethodCallArguments(final ClassNode receiver, ArgumentListEx
                     // GRECLIPSE end
                 }
                 expression.visit(this);
-                if (expression.getNodeMetaData(StaticTypesMarker.DELEGATION_METADATA) != null) {
-                    expression.removeNodeMetaData(StaticTypesMarker.DELEGATION_METADATA);
-                }
+                expression.removeNodeMetaData(StaticTypesMarker.DELEGATION_METADATA);
             }
         }
-        if (expressions.size() > 0 && expressions.get(0) instanceof MapExpression && params.length > 0) {
+        if (params.length > 0 && expressions.get(0) instanceof MapExpression) {
             checkNamedParamsAnnotation(params[0], (MapExpression) expressions.get(0));
         }
     }
diff --git a/base/org.codehaus.groovy30/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java b/base/org.codehaus.groovy30/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java
index 84768bf143..3c30c47133 100644
--- a/base/org.codehaus.groovy30/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java
+++ b/base/org.codehaus.groovy30/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingVisitor.java
@@ -3119,6 +3119,7 @@ protected void silentlyVisitMethodNode(final MethodNode directMethodCallCandidat
     }
 
     protected void visitMethodCallArguments(final ClassNode receiver, final ArgumentListExpression arguments, final boolean visitClosures, final MethodNode selectedMethod) {
+        /* GRECLIPSE edit
         Parameter[] params = selectedMethod != null ? selectedMethod.getParameters() : Parameter.EMPTY_ARRAY;
         List<Expression> expressions = new LinkedList<>(arguments.getExpressions());
         if (selectedMethod instanceof ExtensionMethodNode) {
@@ -3126,7 +3127,17 @@ protected void visitMethodCallArguments(final ClassNode receiver, final Argument
             expressions.add(0, varX("$self", receiver));
         }
         ArgumentListExpression newArgs = args(expressions);
-
+        */
+        Parameter[] params;
+        List<Expression> expressions = new ArrayList<>();
+        if (selectedMethod instanceof ExtensionMethodNode) {
+            params = ((ExtensionMethodNode) selectedMethod).getExtensionMethodNode().getParameters();
+            expressions.add(varX("$self", receiver));
+        } else {
+            params = selectedMethod != null ? selectedMethod.getParameters() : Parameter.EMPTY_ARRAY;
+        }
+        expressions.addAll(arguments.getExpressions());
+        // GRECLIPSE end
         int nExpressions = expressions.size();
         for (int i = 0; i < nExpressions; i += 1) {
             Expression expression = expressions.get(i);
@@ -3136,13 +3147,13 @@ protected void visitMethodCallArguments(final ClassNode receiver, final Argument
                     Parameter target = params[i];
                     ClassNode targetType = target.getType();
                     ClosureExpression source = (ClosureExpression) expression;
-                    checkClosureWithDelegatesTo(receiver, selectedMethod, newArgs, params, source, target);
+                    checkClosureWithDelegatesTo(receiver, selectedMethod, args(expressions), params, source, target);
                     if (selectedMethod instanceof ExtensionMethodNode) {
                         if (i > 0) {
                             inferClosureParameterTypes(receiver, arguments, source, target, selectedMethod);
                         }
                     } else {
-                        inferClosureParameterTypes(receiver, newArgs, source, target, selectedMethod);
+                        inferClosureParameterTypes(receiver, arguments, source, target, selectedMethod);
                     }
                     if (isFunctionalInterface(targetType)) {
                         storeInferredReturnType(source, GenericsUtils.parameterizeSAM(targetType).getV2());