Fix behavior of DeclaredType#mustBeOrExtend for non-class symbols

Author: guillaume-dequenne

python-frontend/src/main/java/org/sonar/python/types/DeclaredType.java

@@ -131,12 +131,13 @@ public boolean isCompatibleWith(InferredType other) {
 
   @Override
   public boolean mustBeOrExtend(String typeName) {
-    return alternativeTypeSymbols().stream().flatMap(a -> {
+    List<Symbol> classSymbols = alternativeTypeSymbols().stream().flatMap(a -> {
       if (a.is(Symbol.Kind.AMBIGUOUS)) {
         return ((AmbiguousSymbol) a).alternatives().stream().filter(alternative -> alternative.is(CLASS));
       }
       return Stream.of(a);
-    }).filter(a -> a.is(CLASS)).allMatch(a -> ((ClassSymbol) a).isOrExtends(typeName));
+    }).filter(a -> a.is(CLASS)).collect(Collectors.toList());
+    return !classSymbols.isEmpty() && classSymbols.stream().allMatch(a -> ((ClassSymbol) a).isOrExtends(typeName));
   }
 
   @Override

python-frontend/src/test/java/org/sonar/python/types/DeclaredTypeTest.java

@@ -169,9 +169,9 @@ public void test_mustBeOrExtend() {
     assertThat(typeAmbiguousX1.mustBeOrExtend("other")).isFalse();
 
     DeclaredType declaredType = new DeclaredType(new SymbolImpl("C", "foo.C"));
-    assertThat(declaredType.mustBeOrExtend("other")).isTrue();
-    assertThat(declaredType.mustBeOrExtend("foo.C")).isTrue();
-    assertThat(declaredType.mustBeOrExtend("C")).isTrue();
+    assertThat(declaredType.mustBeOrExtend("other")).isFalse();
+    assertThat(declaredType.mustBeOrExtend("foo.C")).isFalse();
+    assertThat(declaredType.mustBeOrExtend("C")).isFalse();
   }
 
   @Test