Also update parse error test output

python · ilevkivskyi · Aug 9, 2026 · Aug 9, 2026 · Aug 18, 2026 · Aug 19, 2026
commit 049c5fe32c3730efbfed49d242f0d2ae35292df1
diff --git a/mypy/test/testparse.py b/mypy/test/testparse.py
@@ -13,6 +13,7 @@
 from mypy.parse import parse
 from mypy.test.data import DataDrivenTestCase, DataSuite
 from mypy.test.helpers import assert_string_arrays_equal, find_test_files, parse_options
+from mypy.test.update_data import update_testcase_output
 from mypy.util import get_mypy_comments
 
 
@@ -115,6 +116,11 @@ def test_parse_error(testcase: DataDrivenTestCase) -> None:
     except CompileError as e:
         if e.module_with_blocker is not None:
             assert e.module_with_blocker == "__main__"
+
+        # This may not work perfectly, since it was designed for testcheck.py, use with care.
+        if testcase.output != e.messages and testcase.config.getoption("--update-data", False):
+            update_testcase_output(testcase, e.messages, incremental_step=1)
+
         # Verify that there was a compile error and that the error messages
         # are equivalent.
         assert_string_arrays_equal(

diff --git a/test-data/unit/parse-errors.test b/test-data/unit/parse-errors.test
@@ -18,96 +18,102 @@ file:1: error: Expected ':'
 1
  2
 [out]
-file:2: error: Unexpected indent
+file:2: error: Unexpected indentation
+file:2: error: Expected a statement
 
 [case testInconsistentIndent]
 if x:
   1
    1
 [out]
-file:3: error: Unexpected indent
+file:3: error: Unexpected indentation
+file:3: error: Expected a statement
 
 [case testInconsistentIndent2]
 if x:
    1
   1
 [out]
 file:3: error: Unindent does not match any outer indentation level
+file:3: error: Expected dedent, found end of file
 
 [case testInvalidBinaryOp]
 1>
 a*
 a+1*
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an expression
+file:2: error: Expected an expression
+file:3: error: Expected an expression
 
 [case testDoubleStar]
 **a
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an expression
 
 [case testMissingSuperClass]
 class A(:
   pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an expression or a ')'
+file:1: error: Expected `)`, found newline
 
 [case testUnexpectedEof]
 if 1:
 [out]
-file:1: error: Expected an indented block after 'if' statement on line 1
+file:1: error: Expected an indented block after `if` statement
 
 [case testInvalidKeywordArguments1]
 f(x=y, z)
 [out]
-file:1: error: Positional argument follows keyword argument
+file:1: error: Positional argument cannot follow keyword argument
 
 [case testInvalidKeywordArguments2]
 f(**x, y)
 [out]
-file:1: error: Positional argument follows keyword argument unpacking
+file:1: error: Positional argument cannot follow keyword argument unpacking
 
 [case testInvalidBareAsteriskAndVarArgs2]
 def f(*x: A, *) -> None: pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Keyword-only parameter separator not allowed after '*' parameter
 
 [case testInvalidBareAsteriskAndVarArgs3]
 def f(*, *x: A) -> None: pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Only one '*' parameter allowed
 
 [case testInvalidBareAsteriskAndVarArgs4]
 def f(*, **x: A) -> None: pass
 [out]
-file:1: error: Named arguments must follow bare *
+file:1: error: Expected one or more keyword parameter after `*` separator
 
 [case testInvalidBareAsterisk1]
 def f(*) -> None: pass
 [out]
-file:1: error: Named arguments must follow bare *
+file:1: error: Expected one or more keyword parameter after `*` separator
 
 [case testInvalidBareAsterisk2]
 def f(x, *) -> None: pass
 [out]
-file:1: error: Named arguments must follow bare *
+file:1: error: Expected one or more keyword parameter after `*` separator
 
 [case testInvalidFuncDefArgs1]
 def f(x = y, x): pass
 [out]
-file:1: error: Non-default argument follows default argument
+file:1: error: Parameter without a default cannot follow a parameter with a default
 
 [case testInvalidFuncDefArgs3]
 def f(**x, y):
    pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Parameter cannot follow var-keyword parameter
 
 [case testInvalidFuncDefArgs4]
 def f(**x, y=x):
     pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Parameter cannot follow var-keyword parameter
 
 [case testInvalidTypeComment]
 0
@@ -154,7 +160,7 @@ file:2: error: Syntax error in type comment "A B"
 [case testMissingBracket]
 def foo(
 [out]
-file:1: error: '(' was never closed
+file:1: error: Unexpected EOF while parsing
 
 [case testInvalidSignatureInComment1]
 def f(): # type: x
@@ -203,7 +209,7 @@ file:1: error: Syntax error in type comment "(x) -"
 def f(): # type: (x) ->
   pass
 [out]
-file:1: error: Syntax error in type comment "(x) ->"
+file:1: error: Type signature has too many parameters
 
 [case testInvalidSignatureInComment9]
 def f(): # type: (x) -> .
@@ -281,96 +287,103 @@ file:3: error: Inconsistent use of "**" in function signature
 [case testPrintStatementInPython3]
 print 1
 [out]
-file:1: error: Missing parentheses in call to 'print'. Did you mean print(...)?
+file:1: error: Simple statements must be separated by newlines or semicolons
 
 [case testInvalidConditionInConditionalExpression]
 1 if 2, 3 else 4
 [out]
-file:1: error: Expected 'else' after 'if' expression
+file:1: error: Expected `else`, found `,`
+file:1: error: Expected a statement
 
 [case testInvalidConditionInConditionalExpression2]
 1 if x for y in z else 4
 [out]
-file:1: error: Expected 'else' after 'if' expression
+file:1: error: Expected `else`, found `for`
+file:1: error: Simple statements must be separated by newlines or semicolons
+file:1: error: Expected a statement
 
 [case testInvalidConditionInConditionalExpression3]
 1 if x else for y in z
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an identifier, but found a keyword `for` that cannot be used here
+file:1: error: Simple statements must be separated by newlines or semicolons
 
 [case testYieldFromNotRightParameter]
 def f():
     yield from
 [out]
-file:2: error: Invalid syntax
+file:2: error: Expected an expression
 
 [case testYieldFromAfterReturn]
 def f():
     return yield from h()
 [out]
-file:2: error: Invalid syntax
+file:2: error: Yield expression cannot be used here
 
 [case testImportDotModule]
 import .x
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an import name
 
 [case testImportDot]
 import .
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an import name
+file:1: error: Expected one or more symbol names after import
 
 [case testInvalidFunctionName]
 def while(): pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an identifier, but found a keyword `while` that cannot be used here
 
 [case testInvalidEllipsis1]
 ...0
 ..._
 ...a
 [out]
-file:1: error: Invalid syntax
+file:1: error: Simple statements must be separated by newlines or semicolons
+file:2: error: Simple statements must be separated by newlines or semicolons
+file:3: error: Simple statements must be separated by newlines or semicolons
 
 [case testBlockStatementInSingleLineIf]
 if 1: if 2: pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected a simple statement
 
 [case testBlockStatementInSingleLineIf2]
 if 1: while 2: pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected a simple statement
 
 [case testBlockStatementInSingleLineIf3]
 if 1: for x in y: pass
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected a simple statement
 
 [case testUnexpectedEllipsis]
 a = a...
 [out]
-file:1: error: Invalid syntax
+file:1: error: Simple statements must be separated by newlines or semicolons
 
 [case testParseErrorBeforeUnicodeLiteral]
 x u'y'
 [out]
-file:1: error: Invalid syntax
+file:1: error: Simple statements must be separated by newlines or semicolons
 
 [case testParseErrorInExtendedSlicing]
 x[:,
 [out]
-file:1: error: '[' was never closed
+file:1: error: Unexpected EOF while parsing
 
 [case testParseErrorInExtendedSlicing2]
 x[:,::
 [out]
-file:1: error: '[' was never closed
+file:1: error: Unexpected EOF while parsing
 
 [case testParseErrorInExtendedSlicing3]
 x[:,:
 [out]
-file:1: error: '[' was never closed
+file:1: error: Unexpected EOF while parsing
 
 [case testInvalidEncoding]
 # foo
@@ -407,17 +420,19 @@ file:0: error: Unknown encoding: uft8
 2L
 0x2L
 [out]
-file:1: error: Invalid decimal literal
+file:1: error: Simple statements must be separated by newlines or semicolons
+file:2: error: Simple statements must be separated by newlines or semicolons
 
 [case testPython2LegacyInequalityInPython3]
 1 <> 2
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected an expression
 
 [case testLambdaInListComprehensionInPython3]
 ([ 0 for x in 1, 2 if 3 ])
 [out]
-file:1: error: Invalid syntax
+file:1: error: Expected `]`, found `,`
+file:1: error: Expected `else`, found `]`
 
 [case testTupleArgListInPython3]
 def f(x, (y, z)): pass
@@ -427,12 +442,15 @@ file:1: error: Invalid syntax
 [case testBackquoteInPython3]
 `1 + 2`
 [out]
-file:1: error: Invalid syntax
+file:1: error: Got unexpected token `
+file:1: error: Expected a statement
 
 [case testSmartQuotes]
 foo = ‘bar’
 [out]
-file:1: error: Invalid character '‘' (U+2018)
+file:1: error: Got unexpected token ‘
+file:1: error: Got unexpected token ’
+file:1: error: Expected a statement
 
 [case testExceptCommaInPython3]
 try: