IDEA-167588 Uncompilable code after conversion Stream -> Loop with unknown Stream sources

java/java-impl/src/com/intellij/codeInspection/streamToLoop/SourceOperation.java

@@ -108,7 +108,10 @@ abstract class SourceOperation extends Operation {
       return new ForEachSource(args[0]);
     }
     if (supportUnknownSources) {
-      return new StreamIteratorSource(call);
+      PsiType type = StreamApiUtil.getStreamElementType(call.getType(), false);
+      if (type != null) {
+        return new StreamIteratorSource(call, type);
+      }
     }
     return null;
   }
@@ -312,10 +315,12 @@ abstract class SourceOperation extends Operation {
   }
 
   private static class StreamIteratorSource extends SourceOperation {
+    private final String myElementType;
     private PsiMethodCallExpression myCall;
 
-    public StreamIteratorSource(PsiMethodCallExpression call) {
+    public StreamIteratorSource(PsiMethodCallExpression call, PsiType type) {
       myCall = call;
+      myElementType = type.getCanonicalText();
     }
 
     @Override
@@ -355,7 +360,7 @@ abstract class SourceOperation extends Operation {
     @Override
     String wrap(StreamVariable outVar, String code, StreamToLoopReplacementContext context) {
       String iterator = context.registerVarName(Arrays.asList("it", "iter", "iterator"));
-      String declaration = getIteratorType(outVar.getType()) + " " + iterator + "=" + myCall.getText() + ".iterator()";
+      String declaration = getIteratorType(myElementType) + " " + iterator + "=" + myCall.getText() + ".iterator()";
       String condition = iterator + ".hasNext()";
       return "for(" + declaration + ";" + condition + ";) {\n" +
              outVar.getDeclaration(iterator + ".next()") +

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCustomSource.java

@@ -1,5 +1,6 @@
-// "Replace Stream API chain with loop" "true"
+// "Fix all 'Stream API call chain can be replaced with loop' problems in file" "true"
 
+import java.lang.reflect.Array;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
@@ -21,4 +22,17 @@ public class Test {
           }
       }
   }
+
+  private long counter(Class<? extends Array> list) {
+      long count = 0L;
+      for (Iterator<? extends Array> it = stream(list).iterator(); it.hasNext(); ) {
+          Array array = it.next();
+          count++;
+      }
+      return count;
+  }
+
+  public <E> Stream<E> stream(Class<E> clazz) {
+    return null;
+  }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCustomSource.java

@@ -1,5 +1,6 @@
-// "Replace Stream API chain with loop" "true"
+// "Fix all 'Stream API call chain can be replaced with loop' problems in file" "true"
 
+import java.lang.reflect.Array;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -13,4 +14,12 @@ public class Test {
     List<String> list = new Test().names().map(String::trim).filter(n -> !n.isEmpty())
       .<caret>collect(Collectors.toList());
   }
+
+  private long counter(Class<? extends Array> list) {
+    return stream(list).count();
+  }
+
+  public <E> Stream<E> stream(Class<E> clazz) {
+    return null;
+  }
 }

plugins/InspectionGadgets/src/com/siyeh/ig/psiutils/StreamApiUtil.java

@@ -29,6 +29,11 @@ import org.jetbrains.annotations.Nullable;
 public class StreamApiUtil {
   @Contract("null -> null")
   public static PsiType getStreamElementType(PsiType type) {
+    return getStreamElementType(type, true);
+  }
+
+  @Contract("null, _ -> null")
+  public static PsiType getStreamElementType(PsiType type, boolean variableType) {
     if(!(type instanceof PsiClassType)) return null;
     PsiClass aClass = ((PsiClassType)type).resolve();
     if(com.intellij.psi.util.InheritanceUtil.isInheritor(aClass, false, CommonClassNames.JAVA_UTIL_STREAM_INT_STREAM)) {
@@ -44,8 +49,8 @@ public class StreamApiUtil {
       return null;
     }
     PsiType streamType = PsiUtil.substituteTypeParameter(type, CommonClassNames.JAVA_UTIL_STREAM_STREAM, 0, false);
-    if(streamType instanceof PsiCapturedWildcardType) {
-      streamType = ((PsiCapturedWildcardType)streamType).getUpperBound();
+    if (variableType) {
+      streamType = GenericsUtil.getVariableTypeByExpressionType(streamType);
     }
     return streamType;
   }