IDEA-168578 Broken type inference in range expressions

java/java-psi-api/src/com/intellij/psi/PsiPrimitiveType.java

@@ -139,6 +139,11 @@ public class PsiPrimitiveType extends PsiType.Stub {
     return unboxed.annotate(type.getAnnotationProvider());
   }
 
+  @Nullable
+  public static PsiPrimitiveType getOptionallyUnboxedType(PsiType type) {
+    return type instanceof PsiPrimitiveType ? (PsiPrimitiveType)type : getUnboxedType(type);
+  }
+
   public String getBoxedTypeName() {
     return ourUnboxedToQName.get(this);
   }

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/TypesUtil.java

@@ -558,14 +558,14 @@ public class TypesUtil implements TypeConstants {
 
   @Nullable
   private static PsiType getNumericLUB(@Nullable PsiType type1, @Nullable PsiType type2) {
-    PsiPrimitiveType unboxedType1 = PsiPrimitiveType.getUnboxedType(type1);
-    PsiPrimitiveType unboxedType2 = PsiPrimitiveType.getUnboxedType(type2);
+    PsiPrimitiveType unboxedType1 = PsiPrimitiveType.getOptionallyUnboxedType(type1);
+    PsiPrimitiveType unboxedType2 = PsiPrimitiveType.getOptionallyUnboxedType(type2);
     if (unboxedType1 != null && unboxedType2 != null) {
       int i1 = LUB_NUMERIC_TYPES.indexOf(unboxedType1);
       int i2 = LUB_NUMERIC_TYPES.indexOf(unboxedType2);
       if (i1 >= 0 && i2 >= 0) {
         if (i1 > i2) return type1;
-        if (i2 > i1) return type2;
+        if (i2 >= i1) return type2;
       }
     }
     return null;

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/resolve/TypeInferenceTest.groovy

@@ -597,6 +597,22 @@ class Any {
 ''', 'java.lang.Object')
   }
 
+  void testRange() {
+    doTest('''\
+        def m = new int[3]
+        for (ii in 0..<m.length) {
+         print i<caret>i
+        }
+''', 'java.lang.Integer')
+
+    doTest('''\
+        def m = new int[3]
+        for (ii in m.size()..< m[0]) {
+         print i<caret>i
+        }
+''', 'java.lang.Integer')
+  }
+
   void testUnary() {
     doExprTest('~/abc/', 'java.util.regex.Pattern')
   }