IDEA-51920 'Suspicious call to Map.get' inspection should be aware of dataflow type information

java/java-impl/src/com/intellij/codeInspection/miscGenerics/SuspiciousCollectionsMethodCallsInspection.java

@@ -16,6 +16,7 @@
 package com.intellij.codeInspection.miscGenerics;
 
 import com.intellij.codeInsight.daemon.GroupNames;
+import com.intellij.codeInsight.guess.GuessManager;
 import com.intellij.codeInspection.InspectionsBundle;
 import com.intellij.codeInspection.ProblemsHolder;
 import com.intellij.codeInspection.ex.BaseLocalInspectionTool;
@@ -133,8 +134,17 @@ public class SuspiciousCollectionsMethodCallsInspection extends BaseLocalInspect
                                                        final IntArrayList indices) {
     final PsiExpression[] args = methodCall.getArgumentList().getExpressions();
     if (args.length != 1) return null;
+
     PsiType argType = args[0].getType();
-    return getSuspiciousMethodCallMessage(methodCall, argType, reportConvertibleMethodCalls, patternMethods, indices);
+    final String plainMessage = getSuspiciousMethodCallMessage(methodCall, argType, reportConvertibleMethodCalls, patternMethods, indices);
+    if (plainMessage != null) {
+      final PsiType dfaType = GuessManager.getInstance(methodCall.getProject()).getControlFlowExpressionType(args[0]);
+      if (dfaType != null && getSuspiciousMethodCallMessage(methodCall, dfaType, reportConvertibleMethodCalls, patternMethods, indices) == null) {
+        return null;
+      }
+    }
+
+    return plainMessage;
   }
 
   @Nullable

java/java-tests/testData/inspection/suspiciousCalls/UseDfa.java

@@ -0,0 +1,11 @@
+import java.lang.Integer;
+import java.util.Map;
+
+class Clazz {
+  void f(Map<Integer, String> map, Object o) {
+    if (o instanceof Integer && map.containsKey(o)) {
+      System.out.println();
+    }
+  }
+
+}

java/java-tests/testSrc/com/intellij/codeInspection/SuspiciousCollectionMethodCallsTest.java

@@ -17,6 +17,7 @@ public class SuspiciousCollectionMethodCallsTest extends LightCodeInsightFixture
     myFixture.testHighlighting(getTestName(false) + ".java");
   }
 
+  public void testUseDfa() throws Exception { doTest(); }
   public void testWildcard() throws Exception { doTest(); }
   public void testIgnoreConvertible() throws Exception {
     myTool.REPORT_CONVERTIBLE_METHOD_CALLS = false;