String is assignable to char

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/api/types/GrClosureSignature.java

@@ -29,6 +29,8 @@ public interface GrClosureSignature {
   @NotNull
   GrClosureParameter[] getParameters();
 
+  int getParameterCount();
+
   boolean isVarargs();
 
   @Nullable

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

@@ -36,7 +36,6 @@ import org.jetbrains.plugins.groovy.lang.psi.GroovyPsiElement;
 import org.jetbrains.plugins.groovy.lang.psi.api.GroovyResolveResult;
 import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrBinaryExpression;
 import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrExpression;
-import org.jetbrains.plugins.groovy.lang.psi.api.types.GrClosureParameter;
 import org.jetbrains.plugins.groovy.lang.psi.api.types.GrClosureSignature;
 import org.jetbrains.plugins.groovy.lang.psi.impl.GrClosureType;
 import org.jetbrains.plugins.groovy.lang.psi.impl.GrTupleType;
@@ -50,6 +49,7 @@ import java.util.Map;
 
 import static com.intellij.psi.CommonClassNames.*;
 import static org.jetbrains.plugins.groovy.lang.lexer.GroovyTokenTypes.*;
+import static org.jetbrains.plugins.groovy.lang.psi.util.GroovyCommonClassNames.GROOVY_LANG_GSTRING;
 import static org.jetbrains.plugins.groovy.lang.psi.util.GroovyCommonClassNames.JAVA_MATH_BIG_DECIMAL;
 import static org.jetbrains.plugins.groovy.lang.psi.util.GroovyCommonClassNames.JAVA_MATH_BIG_INTEGER;
 
@@ -304,6 +304,11 @@ public class TypesUtil {
       lType = boxPrimitiveType(lType, manager, scope);
     }
 
+    if (unboxPrimitiveTypeWrapper(lType) == PsiType.CHAR &&
+        (typeEqualsToText(rType, GROOVY_LANG_GSTRING) || typeEqualsToText(rType, JAVA_LANG_STRING))) {
+      return true;
+    }
+
     return TypeConversionUtil.isAssignable(lType, rType);
 
   }
@@ -393,13 +398,10 @@ public class TypesUtil {
     else if (type1 instanceof GrClosureType && type2 instanceof GrClosureType) {
       GrClosureType clType1 = (GrClosureType)type1;
       GrClosureType clType2 = (GrClosureType)type2;
-      GrClosureSignature signature1=clType1.getSignature();
-      GrClosureSignature signature2=clType2.getSignature();
+      GrClosureSignature signature1 = clType1.getSignature();
+      GrClosureSignature signature2 = clType2.getSignature();
 
-      GrClosureParameter[] parameters1 = signature1.getParameters();
-      GrClosureParameter[] parameters2 = signature2.getParameters();
-
-      if (parameters1.length == parameters2.length) {
+      if (signature1.getParameterCount() == signature2.getParameterCount()) {
         final GrClosureSignature signature = GrClosureSignatureImpl.getLeastUpperBound(signature1, signature2, manager);
         if (signature != null) {
           GlobalSearchScope scope = clType1.getResolveScope().intersectWith(clType2.getResolveScope());

plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrClosureSignatureImpl.java

@@ -82,6 +82,11 @@ public class GrClosureSignatureImpl implements GrClosureSignature {
     return result;
   }
 
+  @Override
+  public int getParameterCount() {
+    return myParameters.length;
+  }
+
   @Nullable
   public GrClosureSignature curry(int count) {
     if (count > myParameters.length) {

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/GroovyHighlightingTest.java

@@ -375,4 +375,8 @@ public class GroovyHighlightingTest extends LightCodeInsightFixtureTestCase {
     doTest(new UnusedDefInspection());
   }
 
+  public void testStringAssignableToChar() {
+    doTest(new GroovyAssignabilityCheckInspection());
+  }
+
 }

plugins/groovy/testdata/highlighting/StringAssignableToChar.groovy

@@ -0,0 +1,3 @@
+def a='string text'
+char ch = a //here should not be inspection warning
+int x = <warning descr="Cannot assign 'String' to 'int'">a</warning> //check that assignability inspection is on.