diff --git a/spacy/errors.py b/spacy/errors.py
index de4ffde3c..27091810d 100644
--- a/spacy/errors.py
+++ b/spacy/errors.py
@@ -690,8 +690,8 @@ class Errors:
              "in more than one span in entities, blocked, missing or outside.")
     E1011 = ("Unsupported default '{default}' in doc.set_ents. Available "
              "options: {modes}")
-    E1012 = ("Spans provided to doc.set_ents must be provided as a list of "
-             "`Span` objects.")
+    E1012 = ("Entity spans and blocked/missing/outside spans should be "
+             "provided to doc.set_ents as lists of `Span` objects.")
     E1013 = ("Unable to set entity for span with empty label. Entity spans are "
              "required to have a label. To set entity information as missing "
              "or blocked, use the keyword arguments with doc.set_ents.")
diff --git a/spacy/tokens/doc.pyx b/spacy/tokens/doc.pyx
index 34742e587..4bf6f0e5e 100644
--- a/spacy/tokens/doc.pyx
+++ b/spacy/tokens/doc.pyx
@@ -8,6 +8,7 @@ from libc.stdint cimport int32_t, uint64_t
 import copy
 from collections import Counter
 from enum import Enum
+import itertools
 import numpy
 import srsly
 from thinc.api import get_array_module
@@ -742,28 +743,7 @@ cdef class Doc:
 
         # Find all tokens covered by spans and check that none are overlapping
         seen_tokens = set()
-        for span in entities:
-            if not isinstance(span, Span):
-                raise ValueError(Errors.E1012.format(span=span))
-            for i in range(span.start, span.end):
-                if i in seen_tokens:
-                    raise ValueError(Errors.E1010.format(i=i))
-                seen_tokens.add(i)
-        for span in blocked:
-            if not isinstance(span, Span):
-                raise ValueError(Errors.E1012.format(span=span))
-            for i in range(span.start, span.end):
-                if i in seen_tokens:
-                    raise ValueError(Errors.E1010.format(i=i))
-                seen_tokens.add(i)
-        for span in missing:
-            if not isinstance(span, Span):
-                raise ValueError(Errors.E1012.format(span=span))
-            for i in range(span.start, span.end):
-                if i in seen_tokens:
-                    raise ValueError(Errors.E1010.format(i=i))
-                seen_tokens.add(i)
-        for span in outside:
+        for span in itertools.chain.from_iterable([entities, blocked, missing, outside]):
             if not isinstance(span, Span):
                 raise ValueError(Errors.E1012.format(span=span))
             for i in range(span.start, span.end):