Introduce JvmAnalysisUastUtil, move everything from ReactorUastUtil here

jvm/jvm-analysis-api/src/com/intellij/codeInspection/JvmAnalysisUastUtil.java

@@ -0,0 +1,86 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.codeInspection;
+
+import com.intellij.openapi.progress.ProgressManager;
+import com.intellij.psi.PsiClass;
+import com.intellij.psi.PsiClassType;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiType;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.uast.*;
+
+public final class JvmAnalysisUastUtil {
+  @Nullable
+  public static UCallExpression getUCallExpression(@NotNull PsiElement element) {
+    UCallExpression callExpression = UastContextKt.toUElement(element, UCallExpression.class);
+    if (callExpression == null) {
+      return null;
+    }
+    // workaround for duplicate warnings on the same element
+    if (callExpression.getSourcePsi() != element) {
+      return null;
+    }
+    return callExpression;
+  }
+
+  @Nullable
+  public static PsiElement getMethodIdentifierSourcePsi(@NotNull UCallExpression callExpression) {
+    UIdentifier methodIdentifier = callExpression.getMethodIdentifier();
+    if (methodIdentifier == null) {
+      return null;
+    }
+    return methodIdentifier.getSourcePsi();
+  }
+
+  @Nullable
+  public static String getExpressionReturnTypePsiClassFqnName(@NotNull UCallExpression expression) {
+    PsiClass psiClass = getTypePsiClass(expression.getReturnType());
+    return psiClass == null ? null : psiClass.getQualifiedName();
+  }
+
+  @Nullable
+  public static PsiClass getTypePsiClass(@Nullable PsiType type) {
+    if (!(type instanceof PsiClassType)) {
+      return null;
+    }
+    return ((PsiClassType)type).rawType().resolve();
+  }
+
+  //TODO use UastContext#isExpressionValueUsed ?
+  public static boolean isExpressionResultValueUsed(@NotNull UCallExpression expression) {
+    UElement currentParent = expression;
+    while ((currentParent = currentParent.getUastParent()) != null) {
+      ProgressManager.checkCanceled();
+
+      if (currentParent instanceof UReturnExpression ||
+          currentParent instanceof ULocalVariable ||
+          currentParent instanceof UField ||
+          currentParent instanceof UBinaryExpression ||
+          currentParent instanceof UCallExpression) {
+        return true;
+      }
+
+      // chain of calls
+      if (currentParent instanceof UQualifiedReferenceExpression) {
+        UExpression selector = ((UQualifiedReferenceExpression)currentParent).getSelector();
+        if (selector instanceof UCallExpression && !selector.equals(expression)) {
+          return true;
+        }
+      }
+
+      if (currentParent instanceof UMethod ||
+          currentParent instanceof UClass ||
+          currentParent instanceof UFile) {
+        break; // no need to go further if we already on method/class/file level; result is not used.
+      }
+    }
+
+    //Kotlin expression-bodies (a workaround for KT-23557)
+    if (currentParent instanceof UMethod && !(((UMethod)currentParent).getUastBody() instanceof UBlockExpression)) {
+      return true;
+    }
+
+    return false;
+  }
+}