Added bounded generic types inference and checking

python/src/com/jetbrains/python/inspections/PyTypeCheckerInspection.java

@@ -93,20 +93,19 @@ public class PyTypeCheckerInspection extends PyInspection {
           final String superName = PythonDocumentationProvider.getTypeName(superType, context);
           String expected = String.format("'%s'", superName);
           final boolean hasGenerics = PyTypeChecker.hasGenerics(superType, context);
+          ProblemHighlightType highlightType = ProblemHighlightType.GENERIC_ERROR_OR_WARNING;
           if (hasGenerics) {
             final PyType subst = PyTypeChecker.substitute(superType, substitutions, context);
             if (subst != null) {
               expected = String.format("'%s' (matched generic type '%s')",
                                        PythonDocumentationProvider.getTypeName(subst, context),
                                        superName);
-
+              highlightType = ProblemHighlightType.WEAK_WARNING;
             }
           }
           final String msg = String.format("Expected type %s, got '%s' instead",
                                            expected,
                                            PythonDocumentationProvider.getTypeName(subType, context));
-          final ProblemHighlightType highlightType = hasGenerics ? ProblemHighlightType.WEAK_WARNING :
-                                                                   ProblemHighlightType.GENERIC_ERROR_OR_WARNING;
           registerProblem(node, msg, highlightType);
           return msg;
         }

python/src/com/jetbrains/python/psi/types/PyGenericType.java

@@ -39,7 +39,7 @@ public class PyGenericType implements PyType {
   @NotNull
   @Override
   public String getName() {
-    return myName;
+    return myBound != null ? myName + " (" + myBound.getName() + ")" : myName;
   }
 
   @Override
@@ -71,7 +71,7 @@ public class PyGenericType implements PyType {
   @NotNull
   @Override
   public String toString() {
-    return "PyGenericType: " + myName;
+    return "PyGenericType: " + getName();
   }
 
   @Nullable

python/src/com/jetbrains/python/psi/types/PyTypeChecker.java

@@ -44,6 +44,32 @@ public class PyTypeChecker {
   private static boolean match(@Nullable PyType expected, @Nullable PyType actual, @NotNull TypeEvalContext context,
                                @Nullable Map<PyGenericType, PyType> substitutions, boolean recursive) {
     // TODO: subscriptable types?, module types?, etc.
+    if (expected instanceof PyGenericType && substitutions != null) {
+      final PyGenericType generic = (PyGenericType)expected;
+      final PyType subst = substitutions.get(generic);
+      final PyType bound = generic.getBound();
+      if (!match(bound, actual, context, substitutions, recursive)) {
+        return false;
+      }
+      else if (subst != null) {
+        if (expected.equals(actual)) {
+          return true;
+        }
+        else if (recursive) {
+          return match(subst, actual, context, substitutions, false);
+        }
+        else {
+          return false;
+        }
+      }
+      else if (actual != null && !(actual instanceof PyReturnTypeReference)) {
+        substitutions.put(generic, actual);
+      }
+      else if (bound != null) {
+        substitutions.put(generic, bound);
+      }
+      return true;
+    }
     if (expected == null || actual == null) {
       return true;
     }
@@ -62,25 +88,6 @@ public class PyTypeChecker {
     if (actual instanceof PyTypeReference) {
       return match(expected, ((PyTypeReference)actual).resolve(null, context), context, substitutions, false);
     }
-    if (expected instanceof PyGenericType && substitutions != null) {
-      final PyGenericType generic = (PyGenericType)expected;
-      final PyType subst = substitutions.get(generic);
-      if (subst != null) {
-        if (expected.equals(actual)) {
-          return true;
-        }
-        else if (recursive) {
-          return match(subst, actual, context, substitutions, false);
-        }
-        else {
-          return false;
-        }
-      }
-      else {
-        substitutions.put(generic, actual);
-        return true;
-      }
-    }
     if (isUnknown(actual)) {
       return true;
     }

python/src/com/jetbrains/python/psi/types/PyUnionType.java

@@ -215,4 +215,9 @@ public class PyUnionType implements PyType {
   public int hashCode() {
     return myMembers.hashCode();
   }
+
+  @Override
+  public String toString() {
+    return "PyUnionType: " + getName();
+  }
 }

python/testData/inspections/PyTypeCheckerInspection/BoundedGeneric.py

@@ -0,0 +1,12 @@
+def test():
+    def f(x):
+        """
+        :type x: T (int or str)
+        :rtype: T
+        """
+        pass
+
+    x = f(10)
+    y = f('foo')
+    z = f(<warning descr="Expected type 'T (one of (int, str))', got 'list' instead">[]</warning>)
+    return x + <warning descr="Expected type 'one of (int, long, float, complex)', got 'str' instead">y</warning>

python/testSrc/com/jetbrains/python/PyTypeTest.java

@@ -572,6 +572,17 @@ public class PyTypeTest extends PyTestCase {
            "    foo(3)\n");
   }
 
+  public void testUpperBoundGeneric() {
+    doTest("int or str",
+           "def foo(x):\n" +
+           "    '''\n" +
+           "    :type x: T (int or str)\n" +
+           "    :rtype: T\n" +
+           "    '''\n" +
+           "def bar(x):\n" +
+           "    expr = foo(x)\n");
+  }
+
   private static TypeEvalContext getTypeEvalContext(@NotNull PyExpression element) {
     return TypeEvalContext.userInitiated(element.getContainingFile()).withTracing();
   }
@@ -594,6 +605,7 @@ public class PyTypeTest extends PyTestCase {
     PyType expected = PyTypeParser.getTypeByName(expr, expectedType);
     if (expected != null) {
       assertNotNull(context.printTrace(), actual);
+      assertFalse(context.printTrace(), actual instanceof PyReturnTypeReference);
       assertTrue(msg(expected, actual, context), PyTypeChecker.match(expected, actual, context));
     }
   }

python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java

@@ -180,4 +180,8 @@ public class PyTypeCheckerInspectionTest extends PyTestCase {
   public void testFieldWithNoneInStub() {
     doMultiFileTest();
   }
+
+  public void testBoundedGeneric() {
+    doTest();
+  }
 }