Added feature to "Convert to expression body" intention: selection for easier explicit type removal

idea/src/org/jetbrains/jet/plugin/intentions/ConvertToExpressionBodyAction.kt

@@ -25,6 +25,10 @@ import org.jetbrains.jet.plugin.JetBundle
 import org.jetbrains.jet.lang.psi.*
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns
 import org.jetbrains.jet.lexer.JetTokens
+import com.intellij.openapi.util.TextRange
+import org.jetbrains.jet.lang.psi.psiUtil.siblings
+import org.jetbrains.jet.plugin.caches.resolve.getLazyResolveSession
+import org.jetbrains.jet.lang.descriptors.DeclarationDescriptorWithVisibility
 
 public class ConvertToExpressionBodyAction : PsiElementBaseIntentionAction() {
     override fun getFamilyName(): String = JetBundle.message("convert.to.expression.body.action.family.name")
@@ -48,6 +52,19 @@ public class ConvertToExpressionBodyAction : PsiElementBaseIntentionAction() {
         val body = declaration.getBodyExpression()!!
         declaration.addBefore(JetPsiFactory(declaration).createEQ(), body)
         body.replace(value)
+
+        if (declaration.hasDeclaredReturnType() && declaration is JetCallableDeclaration && canOmitType(declaration)) {
+            val typeRef = declaration.getTypeReference()!!
+            val colon = typeRef.siblings(forward = false, withItself = false).first { it.getNode().getElementType() == JetTokens.COLON }
+            val range = TextRange(colon.getTextRange().getStartOffset(), typeRef.getTextRange().getEndOffset())
+            editor.getSelectionModel().setSelection(range.getStartOffset(), range.getEndOffset())
+            editor.getCaretModel().moveToOffset(range.getEndOffset())
+        }
+    }
+
+    private fun canOmitType(declaration: JetCallableDeclaration): Boolean {
+        val descriptor = declaration.getLazyResolveSession().resolveToDescriptor(declaration)
+        return !((descriptor as? DeclarationDescriptorWithVisibility)?.getVisibility()?.isPublicAPI() ?: false)
     }
 
     private data class Data(val declaration: JetDeclarationWithBody, val value: JetExpression)

idea/testData/intentions/convertToExpressionBody/anonymousObjectExpression.kt.after

@@ -2,7 +2,7 @@ trait I {
     fun foo(): String
 }
 
-fun bar(): I = object: I {
+fun bar()<selection>: I</selection> = object: I {
     override fun foo(): String {
         return "a"
     }

idea/testData/intentions/convertToExpressionBody/funWithImplicitUnitTypeWithThrow.kt.after

@@ -1,3 +1,3 @@
 // WITH_RUNTIME
 
-fun foo(): Unit = throw UnsupportedOperationException()
+fun foo()<selection>: Unit</selection> = throw UnsupportedOperationException()

idea/testData/intentions/convertToExpressionBody/funWithNothingType.kt.after

@@ -1,3 +1,3 @@
 // WITH_RUNTIME
 
-fun foo(): Nothing = throw UnsupportedOperationException()
+fun foo()<selection>: Nothing</selection> = throw UnsupportedOperationException()

idea/testData/intentions/convertToExpressionBody/funWithReturn.kt.after

@@ -1 +1 @@
-fun foo(): String = "abc"
+fun foo()<selection>: String</selection> = "abc"

idea/testData/intentions/convertToExpressionBody/funWithUnitTypeWithThrow.kt.after

@@ -1,3 +1,3 @@
 // WITH_RUNTIME
 
-fun foo(): Unit = throw UnsupportedOperationException()
+fun foo()<selection>: Unit</selection> = throw UnsupportedOperationException()

idea/testData/intentions/convertToExpressionBody/protectedFunNoSelection.kt

@@ -0,0 +1,5 @@
+open class A {
+    protected fun <caret>foo(): String {
+        return "abc"
+    }
+}

idea/testData/intentions/convertToExpressionBody/protectedFunNoSelection.kt.after

@@ -0,0 +1,3 @@
+open class A {
+    protected fun <caret>foo(): String = "abc"
+}

idea/testData/intentions/convertToExpressionBody/publicFunNoSelection.kt

@@ -0,0 +1,3 @@
+public fun <caret>foo(): String {
+    return "abc"
+}

idea/testData/intentions/convertToExpressionBody/publicFunNoSelection.kt.after

@@ -0,0 +1 @@
+public fun <caret>foo(): String = "abc"

idea/tests/org/jetbrains/jet/plugin/intentions/IntentionTestGenerated.java

@@ -3138,6 +3138,18 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("protectedFunNoSelection.kt")
+        public void testProtectedFunNoSelection() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/protectedFunNoSelection.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("publicFunNoSelection.kt")
+        public void testPublicFunNoSelection() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/publicFunNoSelection.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("returnWithNoValue.kt")
         public void testReturnWithNoValue() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/intentions/convertToExpressionBody/returnWithNoValue.kt");