fix #1421

TestSuite/errors/err0296.pas

@@ -0,0 +1,12 @@
+type
+  t1 = class end;
+  t2 = class end;
+  i1 = interface end;
+
+begin
+  var a1: t1;
+  var a2: t2;
+  var a3: i1;
+  
+  if a1 is t2(var o) then;
+end.

TestSuite/errors/err0297.pas

@@ -0,0 +1,12 @@
+type
+  t1 = class end;
+  t2 = class end;
+  i1 = interface end;
+
+begin
+  var a1: t1;
+  var a2: t2;
+  var a3: i1;
+  
+  if a2 is t1(var o) then; 
+end.

TestSuite/errors/err0298.pas

@@ -0,0 +1,12 @@
+type
+  t1 = class end;
+  t2 = class end;
+  i1 = interface end;
+
+begin
+  var a1: t1;
+  var a2: t2;
+  var a3: i1;
+  
+  if a3 is t1(var o) then;
+end.

TestSuite/errors/err0299.pas

@@ -0,0 +1,12 @@
+type
+  t1 = class end;
+  t2 = class end;
+  i1 = interface end;
+
+begin
+  var a1: t1;
+  var a2: t2;
+  var a3: i1;
+  
+  if a3 is t2(var o) then; 
+end.

TestSuite/patterns-types-interfaces-matching.pas

@@ -0,0 +1,18 @@
+type
+  t1 = class end;
+  t2 = class end;
+  i1 = interface end;
+
+begin
+  var a1: t1;
+  var a2: t2;
+  var a3: i1;
+  
+  if a1 is t1(var o) then;     
+  if a1 is i1(var o) then;  
+  
+  if a2 is t2(var o) then;    
+  if a2 is i1(var o) then;   
+  
+  if a3 is i1(var o) then; 
+end.

TreeConverter/TreeConversion/SyntaxTreeVisitorNodes/Patterns.cs

@@ -254,7 +254,7 @@ namespace PascalABCCompiler.TreeConverter
             if (type_table.is_derived(type, expression) ||
                 type_table.is_derived(expression, type) ||
                 AreTheSameType(type, expression) ||
-                type.IsInterface && expression.IsInterface)
+                type.IsInterface)
                 return;
 
             AddError(get_location(matchedExpression), "EXPRESSION_OF_TYPE_{0}_CANNOT_BE_MATCHED_AGAINST_PATTERN_WITH_TYPE_{1}", expression.name, type.name);