Highlighting variable called as function.

idea/src/org/jetbrains/jet/plugin/JetBundle.properties

@@ -90,6 +90,7 @@ options.jet.attribute.descriptor.fun.call=Function call
 options.jet.attribute.descriptor.namespace.fun.call=Package-level function call
 options.jet.attribute.descriptor.extension.fun.call=Extension function call
 options.jet.attribute.descriptor.constructor.call=Constructor call
+options.jet.attribute.descriptor.variable.as.function.call=Variable as function call
 options.jet.attribute.descriptor.auto.casted=Smart-cast value
 options.jet.attribute.descriptor.label=Label
 change.to.function.invocation=Change to function invocation

idea/src/org/jetbrains/jet/plugin/highlighter/FunctionsHighlightingVisitor.java

@@ -72,6 +72,15 @@ public class FunctionsHighlightingVisitor extends AfterAnalysisHighlightingVisit
                         JetPsiChecker.highlightName(holder, callee, JetHighlightingColors.EXTENSION_FUNCTION_CALL);
                     }
                 }
+                else if (calleeDescriptor instanceof VariableDescriptor) {
+                    String kind = calleeDescriptor instanceof ValueParameterDescriptor
+                                  ? "parameter"
+                                  : calleeDescriptor instanceof PropertyDescriptor
+                                    ? "property"
+                                    : "variable";
+                    holder.createInfoAnnotation(callee, "Calling " + kind + " as function").setTextAttributes(
+                            JetHighlightingColors.VARIABLE_AS_FUNCTION_CALL);
+                }
             }
         }
 

idea/src/org/jetbrains/jet/plugin/highlighter/JetColorSettingsPage.java

@@ -61,7 +61,7 @@ public class JetColorSettingsPage implements ColorSettingsPage {
                "    fun <FUNCTION_DECLARATION>foo</FUNCTION_DECLARATION>(<PARAMETER>nullable</PARAMETER> : String?, <PARAMETER>r</PARAMETER> : <TRAIT>Runnable</TRAIT>, <PARAMETER>f</PARAMETER> : () -> Int) {\n" +
                "        <FUNCTION_CALL><NAMESPACE_FUNCTION_CALL>println</NAMESPACE_FUNCTION_CALL></FUNCTION_CALL>(\"length\\nis ${<PARAMETER>nullable</PARAMETER><SAFE_ACCESS>?.</SAFE_ACCESS><INSTANCE_PROPERTY>length</INSTANCE_PROPERTY>} <INVALID_STRING_ESCAPE><STRING_ESCAPE>\\e</STRING_ESCAPE></INVALID_STRING_ESCAPE>\")\n" +
                "        val <LOCAL_VARIABLE>ints</LOCAL_VARIABLE> = java.util.<CONSTRUCTOR_CALL>ArrayList</CONSTRUCTOR_CALL><Int?>(2)\n" +
-               "        <LOCAL_VARIABLE>ints</LOCAL_VARIABLE>[0] = 102 + <PARAMETER>f</PARAMETER>()\n" +
+               "        <LOCAL_VARIABLE>ints</LOCAL_VARIABLE>[0] = 102 + <PARAMETER><VARIABLE_AS_FUNCTION_CALL>f</VARIABLE_AS_FUNCTION_CALL></PARAMETER>()\n" +
                "        val <LOCAL_VARIABLE>myFun</LOCAL_VARIABLE> = <FUNCTION_LITERAL_BRACES_AND_ARROW>{</FUNCTION_LITERAL_BRACES_AND_ARROW> <FUNCTION_LITERAL_BRACES_AND_ARROW>-></FUNCTION_LITERAL_BRACES_AND_ARROW> \"\" <FUNCTION_LITERAL_BRACES_AND_ARROW>}</FUNCTION_LITERAL_BRACES_AND_ARROW>; var <LOCAL_VARIABLE><MUTABLE_VARIABLE><WRAPPED_INTO_REF>ref</WRAPPED_INTO_REF></MUTABLE_VARIABLE></LOCAL_VARIABLE> = <LOCAL_VARIABLE>ints</LOCAL_VARIABLE>.<FUNCTION_CALL>size</FUNCTION_CALL>()\n" +
                "        if (!<LOCAL_VARIABLE>ints</LOCAL_VARIABLE>.<EXTENSION_PROPERTY><NAMESPACE_PROPERTY>empty</NAMESPACE_PROPERTY></EXTENSION_PROPERTY>) {\n" +
                "            <LOCAL_VARIABLE>ints</LOCAL_VARIABLE>.<EXTENSION_FUNCTION_CALL><NAMESPACE_FUNCTION_CALL><FUNCTION_CALL>forEach</FUNCTION_CALL></NAMESPACE_FUNCTION_CALL></EXTENSION_FUNCTION_CALL> @lit <FUNCTION_LITERAL_BRACES_AND_ARROW>{</FUNCTION_LITERAL_BRACES_AND_ARROW>\n" +
@@ -154,6 +154,7 @@ public class JetColorSettingsPage implements ColorSettingsPage {
             new AttributesDescriptor(JetBundle.message("options.jet.attribute.descriptor.namespace.fun.call"), JetHighlightingColors.NAMESPACE_FUNCTION_CALL),
             new AttributesDescriptor(JetBundle.message("options.jet.attribute.descriptor.extension.fun.call"), JetHighlightingColors.EXTENSION_FUNCTION_CALL),
             new AttributesDescriptor(JetBundle.message("options.jet.attribute.descriptor.constructor.call"), JetHighlightingColors.CONSTRUCTOR_CALL),
+            new AttributesDescriptor(JetBundle.message("options.jet.attribute.descriptor.variable.as.function.call"), JetHighlightingColors.VARIABLE_AS_FUNCTION_CALL),
 
             new AttributesDescriptor(OptionsBundle.message("options.java.attribute.descriptor.bad.character"), JetHighlightingColors.BAD_CHARACTER),
 

idea/src/org/jetbrains/jet/plugin/highlighter/JetHighlightingColors.java

@@ -236,6 +236,11 @@ public class JetHighlightingColors {
         CodeInsightColors.CONSTRUCTOR_CALL_ATTRIBUTES.getDefaultAttributes()
     );
 
+    public static final TextAttributesKey VARIABLE_AS_FUNCTION_CALL = TextAttributesKey.createTextAttributesKey(
+        "KOTLIN_VARIABLE_AS_FUNCTION",
+        new TextAttributes(null, new Color(0xdbffdb), null, null, Font.PLAIN)
+    );
+
     public static final TextAttributesKey BAD_CHARACTER = TextAttributesKey.createTextAttributesKey(
         "KOTLIN_BAD_CHARACTER",
         HighlighterColors.BAD_CHARACTER.getDefaultAttributes()

idea/testData/checker/infos/VariableAsFunction.kt

@@ -0,0 +1,19 @@
+class FunctionLike {
+    fun invoke() {
+    }
+}
+
+val <info>property</info> = {}
+
+fun foo(param: (Int) -> Int, functionLike: FunctionLike) {
+    <info descr="Calling parameter as function">param</info>(1)
+    <info descr="Calling parameter as function">functionLike</info>()
+
+    val v1 = param
+    var v2 = param
+
+    <info descr="Calling variable as function">v1</info>(1)
+    <info descr="Calling variable as function">v2</info>(1)
+
+    <info descr="Calling property as function">property</info>()
+}

idea/testData/highlighter/VariablesAsFunctions.kt

@@ -6,7 +6,7 @@ val <info textAttributesKey="KOTLIN_CLASS">Int</info>.<info textAttributesKey="K
 }
 
 fun <info textAttributesKey="KOTLIN_FUNCTION_DECLARATION">foo</info>(<info textAttributesKey="KOTLIN_PARAMETER">a</info> : () -> <info textAttributesKey="KOTLIN_CLASS">Unit</info>) {
-    <info textAttributesKey="KOTLIN_PARAMETER">a</info>()
-    <info textAttributesKey="KOTLIN_NAMESPACE_PROPERTY"><info textAttributesKey="KOTLIN_MUTABLE_VARIABLE">global</info></info>()
-    1.<info textAttributesKey="KOTLIN_EXTENSION_PROPERTY"><info textAttributesKey="KOTLIN_NAMESPACE_PROPERTY">ext</info></info>()
+    <info textAttributesKey="KOTLIN_PARAMETER"><info textAttributesKey="KOTLIN_VARIABLE_AS_FUNCTION">a</info></info>()
+    <info textAttributesKey="KOTLIN_NAMESPACE_PROPERTY"><info textAttributesKey="KOTLIN_MUTABLE_VARIABLE"><info textAttributesKey="KOTLIN_VARIABLE_AS_FUNCTION">global</info></info></info>()
+    1.<info textAttributesKey="KOTLIN_EXTENSION_PROPERTY"><info textAttributesKey="KOTLIN_NAMESPACE_PROPERTY"><info textAttributesKey="KOTLIN_VARIABLE_AS_FUNCTION">ext</info></info></info>()
 }

idea/testData/highlighter/deprecated/Invoke.kt

@@ -5,5 +5,5 @@ deprecated("Use A instead") fun MyRunnable.invoke() {
 
 fun test() {
   val m = MyRunnable()
-  <info descr="'fun invoke()' is deprecated. Use A instead">m()</info>
+  <info descr="'fun invoke()' is deprecated. Use A instead"><info>m</info>()</info>
 }

idea/tests/org/jetbrains/jet/checkers/JetPsiCheckerTestGenerated.java

@@ -414,6 +414,11 @@ public class JetPsiCheckerTestGenerated extends AbstractJetPsiCheckerTest {
             doTestWithInfos("idea/testData/checker/infos/PropertiesWithBackingFields.kt");
         }
 
+        @TestMetadata("VariableAsFunction.kt")
+        public void testVariableAsFunction() throws Exception {
+            doTestWithInfos("idea/testData/checker/infos/VariableAsFunction.kt");
+        }
+
         @TestMetadata("WrapIntoRef.kt")
         public void testWrapIntoRef() throws Exception {
             doTestWithInfos("idea/testData/checker/infos/WrapIntoRef.kt");