Extend range of "use expression body" to left brace..end of return

Range is extended iff we are in DO_NOT_SHOW case,
otherwise just return is highlighted to avoid ugly highlighting
So #KT-19771 Fixed

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

@@ -72,14 +72,26 @@ class UseExpressionBodyInspection(private val convertEmptyToUnit: Boolean) : Abs
                     super.visitDeclaration(declaration)
 
                     declaration as? KtDeclarationWithBody ?: return
-                    val (toHighlight, suffix, highlightType) = statusFor(declaration) ?: return
+                    val (toHighlightElement, suffix, highlightType) = statusFor(declaration) ?: return
+                    // Change range to start with left brace
+                    val hasHighlighting = highlightType != INFORMATION
+                    val toHighlightRange = toHighlightElement?.textRange?.let {
+                        if (hasHighlighting) {
+                            it
+                        }
+                        else {
+                            // Extend range to [left brace..end of highlight element]
+                            val offset = (declaration.blockExpression()?.lBrace?.startOffset ?: it.startOffset) - it.startOffset
+                            it.shiftRight(offset).grown(-offset)
+                        }
+                    }
 
                     holder.registerProblemWithoutOfflineInformation(
                             declaration,
                             "Use expression body instead of $suffix",
                             isOnTheFly,
                             highlightType,
-                            toHighlight?.textRange?.shiftRight(-declaration.startOffset),
+                            toHighlightRange?.shiftRight(-declaration.startOffset),
                             ConvertToExpressionBodyFix()
                     )
                 }

idea/testData/inspectionsLocal/useExpressionBody/leftBrace.kt

@@ -0,0 +1,7 @@
+// HIGHLIGHT: INFORMATION
+// PROBLEM: Use expression body instead of return
+
+fun simple(): Int {<caret>
+    return 1 *
+           (2 + 3)
+}

idea/testData/inspectionsLocal/useExpressionBody/leftBrace.kt.after

@@ -0,0 +1,5 @@
+// HIGHLIGHT: INFORMATION
+// PROBLEM: Use expression body instead of return
+
+fun simple(): Int = 1 *
+       (2 + 3)

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -3965,6 +3965,12 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("leftBrace.kt")
+        public void testLeftBrace() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/useExpressionBody/leftBrace.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("multiLine.kt")
         public void testMultiLine() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/useExpressionBody/multiLine.kt");