Highlighting duplicated and redandant *-imports as unused

idea/src/org/jetbrains/kotlin/idea/inspections/UnusedImportInspection.kt

@@ -47,12 +47,12 @@ import org.jetbrains.kotlin.idea.imports.KotlinImportOptimizer
 import org.jetbrains.kotlin.idea.imports.importableFqNameSafe
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.JetFile
+import org.jetbrains.kotlin.psi.JetImportDirective
 import org.jetbrains.kotlin.psi.JetSimpleNameExpression
 import org.jetbrains.kotlin.psi.psiUtil.getQualifiedElementSelector
 import org.jetbrains.kotlin.resolve.ImportPath
 import org.jetbrains.kotlin.resolve.bindingContextUtil.getReferenceTargets
-import java.util.ArrayList
+import java.util.*
-import java.util.HashSet
 
 class UnusedImportInspection : AbstractKotlinInspection() {
     override fun runForWholeFile() = true
@@ -64,23 +64,41 @@ class UnusedImportInspection : AbstractKotlinInspection() {
 
         val descriptorsToImport = KotlinImportOptimizer.collectDescriptorsToImport(file)
 
+        val directives = file.importDirectives
+        val explicitlyImportedFqNames = directives
+                .asSequence()
+                .map { it.importPath }
+                .filterNotNull()
+                .filter { !it.isAllUnder && !it.hasAlias() }
+                .map { it.fqnPart() }
+                .toSet()
+
         val fqNames = HashSet<FqName>()
         val parentFqNames = HashSet<FqName>()
         for (descriptor in descriptorsToImport) {
             val fqName = descriptor.importableFqNameSafe
             fqNames.add(fqName)
-            val parentFqName = fqName.parent()
+
-            if (!parentFqName.isRoot) {
+            if (fqName !in explicitlyImportedFqNames) { // we don't add parents of explicitly imported fq-names because such imports are not neeeded
-                parentFqNames.add(parentFqName)
+                val parentFqName = fqName.parent()
+                if (!parentFqName.isRoot) {
+                    parentFqNames.add(parentFqName)
+                }
             }
         }
 
         val problems = ArrayList<ProblemDescriptor>()
-        val directives = file.importDirectives
+
+        val importPaths = HashSet<ImportPath>(directives.size())
+
         for (directive in directives) {
             val importPath = directive.importPath ?: continue
             if (importPath.alias != null) continue // highlighting of unused alias imports not supported yet
-            val isUsed = if (importPath.isAllUnder) {
+
+            val isUsed = if (!importPaths.add(importPath)) {
+                false
+            }
+            else if (importPath.isAllUnder) {
                 importPath.fqnPart() in parentFqNames
             }
             else {

idea/testData/inspections/unusedImport/duplicatedImports.kt

@@ -0,0 +1,14 @@
+import java.io.* // used
+import java.io.* // duplicated
+
+import java.util.ArrayList // used
+import java.util.ArrayList // duplicated
+
+import java.sql.* // unused
+import java.sql.* // unused
+
+fun foo(file: File, list: ArrayList<Int>) {
+}
+
+// WITH_RUNTIME
+// FULL_JDK

idea/testData/inspections/unusedImport/inspectionData/expected.xml

@@ -34,4 +34,58 @@
         <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
         <description>Unused import directive</description>
     </problem>
+    
+    <problem>
+        <file>unusedStarWhenExplicit.kt</file>
+        <line>2</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="unusedStarWhenExplicit.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
+
+    <problem>
+        <file>unusedStarWhenExplicit.kt</file>
+        <line>4</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="unusedStarWhenExplicit.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
+
+    <problem>
+        <file>duplicatedImports.kt</file>
+        <line>2</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="duplicatedImports.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
+
+    <problem>
+        <file>duplicatedImports.kt</file>
+        <line>5</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="duplicatedImports.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
+
+    <problem>
+        <file>duplicatedImports.kt</file>
+        <line>7</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="duplicatedImports.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
+
+    <problem>
+        <file>duplicatedImports.kt</file>
+        <line>8</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="duplicatedImports.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
 </problems>

idea/testData/inspections/unusedImport/unusedStarWhenExplicit.kt

@@ -0,0 +1,13 @@
+import java.io.File // used
+import java.io.* // unused because of explicit imports
+import java.io.InputStream // used
+import java.io.OutputStream // unused
+
+import java.util.ArrayList // used
+import java.util.* // used because HashMap is used
+
+fun foo(file: File, input: InputStream, arrayList: ArrayList<Int>, hashMap: HashMap<Int, Char>) {
+}
+
+// WITH_RUNTIME
+// FULL_JDK