return null constant value for unclosed char literals

a better way to fix IDEA-CR-36839 HardcodedFileSeparatorsInspection: don't fail on unclosed char literals

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightUtil.java

@@ -1036,27 +1036,15 @@ public class HighlightUtil extends HighlightUtilBase {
       }
     }
     else if (type == JavaTokenType.CHARACTER_LITERAL) {
-      if (value != null) {
-        if (!StringUtil.endsWithChar(text, '\'')) {
-          String message = JavaErrorMessages.message("unclosed.char.literal");
-          return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(expression).descriptionAndTooltip(message).create();
-        }
-      }
-      else {
+      if (value == null) {
         if (!StringUtil.startsWithChar(text, '\'')) {
           return null;
         }
-        if (StringUtil.endsWithChar(text, '\'')) {
-          if (text.length() == 1) {
-            String message = JavaErrorMessages.message("illegal.line.end.in.character.literal");
-            return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(expression).descriptionAndTooltip(message).create();
-          }
-          text = text.substring(1, text.length() - 1);
-        }
-        else {
-          String message = JavaErrorMessages.message("illegal.line.end.in.character.literal");
+        if (!StringUtil.endsWithChar(text, '\'') || text.length() == 1) {
+          String message = JavaErrorMessages.message("unclosed.char.literal");
           return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(expression).descriptionAndTooltip(message).create();
         }
+        text = text.substring(1, text.length() - 1);
 
         StringBuilder chars = new StringBuilder();
         boolean success = PsiLiteralExpressionImpl.parseStringCharacters(text, chars, null);

java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiLiteralExpressionImpl.java

@@ -134,13 +134,10 @@ public class PsiLiteralExpressionImpl
       return PsiLiteralUtil.parseDouble(text);
     }
     if (type == JavaTokenType.CHARACTER_LITERAL) {
-      if (StringUtil.endsWithChar(text, '\'')) {
-        if (textLength == 1) return null;
-        text = text.substring(1, textLength - 1);
-      }
-      else {
-        text = text.substring(1, textLength);
+      if (textLength == 1 || !StringUtil.endsWithChar(text, '\'')) {
+        return null;
       }
+      text = text.substring(1, textLength - 1);
       StringBuilder chars = new StringBuilder();
       boolean success = parseStringCharacters(text, chars, null);
       if (!success) return null;

java/java-psi-impl/src/messages/JavaErrorMessages.properties

@@ -315,7 +315,6 @@ binary.numbers.must.contain.at.least.one.hexadecimal.digit=Binary numbers must c
 integer.number.too.large=Integer number too large
 long.number.too.large=Long number too large
 malformed.floating.point.literal=Malformed floating point literal
-illegal.line.end.in.character.literal=Illegal line end in character literal
 illegal.escape.character.in.character.literal=Illegal escape character in character literal
 too.many.characters.in.character.literal=Too many characters in character literal
 empty.character.literal=Empty character literal

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/portability/HardcodedFileSeparatorsInspection.java

@@ -146,7 +146,6 @@ public class HardcodedFileSeparatorsInspection extends BaseInspection {
     @Override
     public void visitLiteralExpression(@NotNull PsiLiteralExpression expression) {
       super.visitLiteralExpression(expression);
-      if (expression.getNextSibling() instanceof PsiErrorElement) return;
 
       final PsiType type = expression.getType();
       if (TypeUtils.isJavaLangString(type)) {