Stream API Migration: fix cases when boxed collection is iterated with primitive parameter (inspired by PR https://github.com/JetBrains/intellij-community/pull/455 by FHannes)

java/java-impl/src/com/intellij/codeInspection/streamMigration/StreamApiMigrationInspection.java

@@ -522,6 +522,19 @@ public class StreamApiMigrationInspection extends BaseJavaBatchLocalInspectionTo
     return false;
   }
 
+  static String tryUnbox(PsiVariable variable) {
+    PsiType type = variable.getType();
+    String mapOp = null;
+    if(type.equals(PsiType.INT)) {
+      mapOp = "mapToInt";
+    } else if(type.equals(PsiType.LONG)) {
+      mapOp = "mapToLong";
+    } else if(type.equals(PsiType.DOUBLE)) {
+      mapOp = "mapToDouble";
+    }
+    return mapOp == null ? "" : "."+mapOp+"("+variable.getName()+" -> "+variable.getName()+")";
+  }
+
   private class StreamApiMigrationVisitor extends JavaElementVisitor {
     private final ProblemsHolder myHolder;
     private final boolean myIsOnTheFly;
@@ -1155,7 +1168,7 @@ public class StreamApiMigrationInspection extends BaseJavaBatchLocalInspectionTo
 
     @Override
     String createReplacement() {
-      return ParenthesesUtils.getText(myExpression, ParenthesesUtils.POSTFIX_PRECEDENCE) + ".stream()";
+      return ParenthesesUtils.getText(myExpression, ParenthesesUtils.POSTFIX_PRECEDENCE) + ".stream()" + tryUnbox(myVariable);
     }
 
     @Contract("null, _ -> false")
@@ -1175,7 +1188,8 @@ public class StreamApiMigrationInspection extends BaseJavaBatchLocalInspectionTo
       PsiClass iteratorClass = PsiUtil.resolveClassInClassTypeOnly(iteratedValueType);
       if (collectionClass == null ||
           !InheritanceUtil.isInheritorOrSelf(iteratorClass, collectionClass, true) ||
-          isRawSubstitution(iteratedValueType, collectionClass)) {
+          isRawSubstitution(iteratedValueType, collectionClass) ||
+          !isSupported(statement.getIterationParameter().getType())) {
         return null;
       }
       return new CollectionStream(statement.getIterationParameter(), iteratedValue);

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/afterIntArraySum.java

@@ -0,0 +1,9 @@
+import java.util.Arrays;
+
+// "Replace with sum()" "true"
+public class Main {
+  public int sum(int[] array) {
+      int sum = Arrays.stream(array).sum();
+      return sum;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/afterIntFilterSum.java

@@ -0,0 +1,22 @@
+// "Replace with sum()" "true"
+import java.util.Arrays;
+import java.util.List;
+
+public class Main {
+  public boolean check(Integer x) {
+    return x % 3 == 0;
+  }
+
+  public boolean check(int x) {
+    return x % 2 == 0;
+  }
+
+  public int sum(List<Integer> list) {
+      int sum = list.stream().mapToInt(x -> x).filter(this::check).sum();
+      return sum;
+  }
+
+  public static void main(String[] args) {
+    System.out.println(new Main().sum(Arrays.asList(1,2,3,4,5,6)));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/afterIntSum.java

@@ -0,0 +1,9 @@
+// "Replace with sum()" "true"
+import java.util.List;
+
+public class Main {
+  public int sum(List<Integer> list) {
+      int sum = list.stream().mapToInt(x -> x).sum();
+      return sum;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/afterIntegerSum.java

@@ -0,0 +1,9 @@
+// "Replace with sum()" "true"
+import java.util.List;
+
+public class Main {
+  public int sum(List<Integer> list) {
+      int sum = list.stream().mapToInt(x -> x).sum();
+      return sum;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeFloatSum.java

@@ -0,0 +1,12 @@
+// "Replace with sum()" "false"
+import java.util.List;
+
+public class Main {
+  public int sum(List<Float> list) {
+    int sum = 0;
+    for(float x : li<caret>st) {
+      sum += x;
+    }
+    return sum;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeIntArraySum.java

@@ -0,0 +1,10 @@
+// "Replace with sum()" "true"
+public class Main {
+  public int sum(int[] array) {
+    int sum = 0;
+    for(int x : arr<caret>ay) {
+      sum += x;
+    }
+    return sum;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeIntFilterSum.java

@@ -0,0 +1,26 @@
+// "Replace with sum()" "true"
+import java.util.Arrays;
+import java.util.List;
+
+public class Main {
+  public boolean check(Integer x) {
+    return x % 3 == 0;
+  }
+
+  public boolean check(int x) {
+    return x % 2 == 0;
+  }
+
+  public int sum(List<Integer> list) {
+    int sum = 0;
+    for(int x : li<caret>st) {
+      if(check(x))
+        sum += x;
+    }
+    return sum;
+  }
+
+  public static void main(String[] args) {
+    System.out.println(new Main().sum(Arrays.asList(1,2,3,4,5,6)));
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeIntSum.java

@@ -0,0 +1,12 @@
+// "Replace with sum()" "true"
+import java.util.List;
+
+public class Main {
+  public int sum(List<Integer> list) {
+    int sum = 0;
+    for(int x : li<caret>st) {
+      sum += x;
+    }
+    return sum;
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamApiMigration/beforeIntegerSum.java

@@ -0,0 +1,12 @@
+// "Replace with sum()" "true"
+import java.util.List;
+
+public class Main {
+  public int sum(List<Integer> list) {
+    int sum = 0;
+    for(Integer x : li<caret>st) {
+      sum += x;
+    }
+    return sum;
+  }
+}