From a39ab0122b6dc7d0d3a551c9807e465fb87b4d11 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Mon, 8 Apr 2019 10:26:20 -0700
Subject: [PATCH 01/12] Give ignores expression-wide scope in Python 3.8.

---
 mypy/errors.py        |  8 ++++----
 mypy/fastparse.py     | 34 +++++++++++++++++++++++-----------
 mypy/fastparse2.py    |  4 ++--
 mypy/nodes.py         |  6 +++---
 mypy/strconv.py       |  4 ++--
 mypy/treetransform.py |  2 +-
 6 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/mypy/errors.py b/mypy/errors.py
index 0053e3ec08c4..a5ef2e01b6d6 100644
--- a/mypy/errors.py
+++ b/mypy/errors.py
@@ -114,7 +114,7 @@ class Errors:
     file = ''  # type: str
 
     # Ignore errors on these lines of each file.
-    ignored_lines = None  # type: Dict[str, Set[int]]
+    ignored_lines = None  # type: Dict[str, Dict[int, int]]
 
     # Lines on which an error was actually ignored.
     used_ignored_lines = None  # type: Dict[str, Set[int]]
@@ -199,7 +199,7 @@ def set_file(self, file: str,
         self.scope = scope
 
     def set_file_ignored_lines(self, file: str,
-                               ignored_lines: Set[int],
+                               ignored_lines: Dict[int, int],
                                ignore_all: bool = False) -> None:
         self.ignored_lines[file] = ignored_lines
         if ignore_all:
@@ -278,7 +278,7 @@ def add_error_info(self, info: ErrorInfo) -> None:
         if not info.blocker:  # Blockers cannot be ignored
             if file in self.ignored_lines and line in self.ignored_lines[file]:
                 # Annotation requests us to ignore all errors on this line.
-                self.used_ignored_lines[file].add(line)
+                self.used_ignored_lines[file].add(self.ignored_lines[file][line])
                 return
             if file in self.ignored_files:
                 return
@@ -300,7 +300,7 @@ def clear_errors_in_targets(self, path: str, targets: Set[str]) -> None:
             self.error_info_map[path] = new_errors
 
     def generate_unused_ignore_notes(self, file: str) -> None:
-        ignored_lines = self.ignored_lines[file]
+        ignored_lines = set(self.ignored_lines[file].values())
         if not self.is_typeshed_file(file) and file not in self.ignored_files:
             for line in ignored_lines - self.used_ignored_lines[file]:
                 # Don't use report since add_error_info will ignore the error!
diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index d47e1a97148d..3e66ce4821bf 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -171,7 +171,7 @@ def parse(source: Union[str, bytes],
         tree.is_stub = is_stub_file
     except SyntaxError as e:
         errors.report(e.lineno, e.offset, e.msg, blocker=True)
-        tree = MypyFile([], [], False, set())
+        tree = MypyFile([], [], False, {})
 
     if raise_on_error and errors.is_errors():
         errors.raise_error()
@@ -251,7 +251,7 @@ def __init__(self,
         self.is_stub = is_stub
         self.errors = errors
 
-        self.extra_type_ignores = []  # type: List[int]
+        self.type_ignores = {}  # type: Dict[int, int]
 
         # Cache of visit_X methods keyed by type of visited object
         self.visitor_cache = {}  # type: Dict[type, Callable[[Optional[AST]], Any]]
@@ -271,8 +271,20 @@ def visit(self, node: Optional[AST]) -> Any:
             method = 'visit_' + node.__class__.__name__
             visitor = getattr(self, method)
             self.visitor_cache[typeobj] = visitor
+        if (3, 8) < sys.version_info and isinstance(node, ast3.expr):
+            self.scope_ignores(node)
         return visitor(node)
 
+    def scope_ignores(self, node: ast3.expr) -> None:
+        end_lineno = getattr(node, "end_lineno", None)
+        if end_lineno is None:
+            return
+        node_lines = range(node.lineno, end_lineno + 1)
+        for line in node_lines:
+            if line in self.type_ignores.values():
+                self.type_ignores.update(dict.fromkeys(node_lines, line))
+                return
+
     def set_line(self, node: N, n: Union[ast3.expr, ast3.stmt]) -> N:
         node.line = n.lineno
         node.column = n.col_offset
@@ -394,13 +406,13 @@ def translate_module_id(self, id: str) -> str:
         return id
 
     def visit_Module(self, mod: ast3.Module) -> MypyFile:
+        self.type_ignores = {ti.lineno: ti.lineno for ti in mod.type_ignores}
         body = self.fix_function_overloads(self.translate_stmt_list(mod.body))
-        ignores = [ti.lineno for ti in mod.type_ignores]
-        ignores.extend(self.extra_type_ignores)
+        self.type_ignores.update({ti.lineno: ti.lineno for ti in mod.type_ignores})
         return MypyFile(body,
                         self.imports,
                         False,
-                        set(ignores),
+                        self.type_ignores,
                         )
 
     # --- stmt ---
@@ -596,7 +608,7 @@ def make_argument(self, arg: ast3.arg, default: Optional[ast3.expr], kind: int,
             elif type_comment is not None:
                 extra_ignore, arg_type = parse_type_comment(type_comment, arg.lineno, self.errors)
                 if extra_ignore:
-                    self.extra_type_ignores.append(arg.lineno)
+                    self.type_ignores[arg.lineno] = arg.lineno
 
         return Argument(Var(arg.arg), arg_type, self.visit(default), kind)
 
@@ -654,7 +666,7 @@ def visit_Assign(self, n: ast3.Assign) -> AssignmentStmt:
         if n.type_comment is not None:
             extra_ignore, typ = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.extra_type_ignores.append(n.lineno)
+                self.type_ignores[n.lineno] = n.lineno
         else:
             typ = None
         s = AssignmentStmt(lvalues, rvalue, type=typ, new_syntax=False)
@@ -688,7 +700,7 @@ def visit_For(self, n: ast3.For) -> ForStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.extra_type_ignores.append(n.lineno)
+                self.type_ignores[n.lineno] = n.lineno
         else:
             target_type = None
         node = ForStmt(self.visit(n.target),
@@ -703,7 +715,7 @@ def visit_AsyncFor(self, n: ast3.AsyncFor) -> ForStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.extra_type_ignores.append(n.lineno)
+                self.type_ignores[n.lineno] = n.lineno
         else:
             target_type = None
         node = ForStmt(self.visit(n.target),
@@ -734,7 +746,7 @@ def visit_With(self, n: ast3.With) -> WithStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.extra_type_ignores.append(n.lineno)
+                self.type_ignores[n.lineno] = n.lineno
         else:
             target_type = None
         node = WithStmt([self.visit(i.context_expr) for i in n.items],
@@ -748,7 +760,7 @@ def visit_AsyncWith(self, n: ast3.AsyncWith) -> WithStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.extra_type_ignores.append(n.lineno)
+                self.type_ignores[n.lineno] = n.lineno
         else:
             target_type = None
         s = WithStmt([self.visit(i.context_expr) for i in n.items],
diff --git a/mypy/fastparse2.py b/mypy/fastparse2.py
index 95f415c629cb..66cee7c994da 100644
--- a/mypy/fastparse2.py
+++ b/mypy/fastparse2.py
@@ -113,7 +113,7 @@ def parse(source: Union[str, bytes],
         tree.is_stub = is_stub_file
     except SyntaxError as e:
         errors.report(e.lineno, e.offset, e.msg, blocker=True)
-        tree = MypyFile([], [], False, set())
+        tree = MypyFile([], [], False, {})
 
     if raise_on_error and errors.is_errors():
         errors.raise_error()
@@ -308,7 +308,7 @@ def visit_Module(self, mod: ast27.Module) -> MypyFile:
         return MypyFile(body,
                         self.imports,
                         False,
-                        set(ignores),
+                        {line: line for line in ignores},
                         )
 
     # --- stmt ---
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 06be60b0f6fe..67b11738cf09 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -227,7 +227,7 @@ class MypyFile(SymbolNode):
     # All import nodes within the file (also ones within functions etc.)
     imports = None  # type: List[ImportBase]
     # Lines to ignore when checking
-    ignored_lines = None  # type: Set[int]
+    ignored_lines = None  # type: Dict[int, int]
     # Is this file represented by a stub file (.pyi)?
     is_stub = False
     # Is this loaded from the cache and thus missing the actual body of the file?
@@ -243,7 +243,7 @@ def __init__(self,
                  defs: List[Statement],
                  imports: List['ImportBase'],
                  is_bom: bool = False,
-                 ignored_lines: Optional[Set[int]] = None) -> None:
+                 ignored_lines: Optional[Dict[int, int]] = None) -> None:
         super().__init__()
         self.defs = defs
         self.line = 1  # Dummy line number
@@ -254,7 +254,7 @@ def __init__(self,
         if ignored_lines:
             self.ignored_lines = ignored_lines
         else:
-            self.ignored_lines = set()
+            self.ignored_lines = {}
 
     def local_definitions(self) -> Iterator[Definition]:
         """Return all definitions within the module (including nested).
diff --git a/mypy/strconv.py b/mypy/strconv.py
index 87f7bd97af71..d47d16cd479c 100644
--- a/mypy/strconv.py
+++ b/mypy/strconv.py
@@ -97,8 +97,8 @@ def visit_mypy_file(self, o: 'mypy.nodes.MypyFile') -> str:
             # case# output in all platforms.
             a.insert(0, o.path.replace(os.sep, '/'))
         if o.ignored_lines:
-            a.append('IgnoredLines(%s)' % ', '.join(str(line)
-                                                    for line in sorted(o.ignored_lines)))
+            a.append('IgnoredLines(%s)' % ', '.join(
+                str(line) for line in sorted(set(o.ignored_lines.values()))))
         return self.dump(a, o)
 
     def visit_import(self, o: 'mypy.nodes.Import') -> str:
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index f4bc96e39db6..0ab7fe89926f 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -60,7 +60,7 @@ def __init__(self) -> None:
     def visit_mypy_file(self, node: MypyFile) -> MypyFile:
         # NOTE: The 'names' and 'imports' instance variables will be empty!
         new = MypyFile(self.statements(node.defs), [], node.is_bom,
-                       ignored_lines=set(node.ignored_lines))
+                       ignored_lines=node.ignored_lines)
         new._fullname = node._fullname
         new.path = node.path
         new.names = SymbolTable()

From 6b066e205b7a8aa83e64bcc0b3c6785d99597beb Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Mon, 8 Apr 2019 17:49:56 -0700
Subject: [PATCH 02/12] Add scoped ignore tests and fix nesting issues.

---
 mypy/fastparse.py            |  6 +++---
 mypy/test/testcheck.py       |  3 +++
 test-data/unit/check-38.test | 21 +++++++++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 test-data/unit/check-38.test

diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index 3e66ce4821bf..bc8264510744 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -271,9 +271,10 @@ def visit(self, node: Optional[AST]) -> Any:
             method = 'visit_' + node.__class__.__name__
             visitor = getattr(self, method)
             self.visitor_cache[typeobj] = visitor
+        result = visitor(node)
         if (3, 8) < sys.version_info and isinstance(node, ast3.expr):
             self.scope_ignores(node)
-        return visitor(node)
+        return result
 
     def scope_ignores(self, node: ast3.expr) -> None:
         end_lineno = getattr(node, "end_lineno", None)
@@ -282,7 +283,7 @@ def scope_ignores(self, node: ast3.expr) -> None:
         node_lines = range(node.lineno, end_lineno + 1)
         for line in node_lines:
             if line in self.type_ignores.values():
-                self.type_ignores.update(dict.fromkeys(node_lines, line))
+                self.type_ignores = {**dict.fromkeys(node_lines, line), **self.type_ignores}
                 return
 
     def set_line(self, node: N, n: Union[ast3.expr, ast3.stmt]) -> N:
@@ -408,7 +409,6 @@ def translate_module_id(self, id: str) -> str:
     def visit_Module(self, mod: ast3.Module) -> MypyFile:
         self.type_ignores = {ti.lineno: ti.lineno for ti in mod.type_ignores}
         body = self.fix_function_overloads(self.translate_stmt_list(mod.body))
-        self.type_ignores.update({ti.lineno: ti.lineno for ti in mod.type_ignores})
         return MypyFile(body,
                         self.imports,
                         False,
diff --git a/mypy/test/testcheck.py b/mypy/test/testcheck.py
index e089b2ad590e..26048972524e 100644
--- a/mypy/test/testcheck.py
+++ b/mypy/test/testcheck.py
@@ -85,6 +85,9 @@
     'check-newsemanal.test',
 ]
 
+if (3, 8) < sys.version_info:
+    typecheck_files.append('check-38.test')
+
 
 class TypeCheckSuite(DataSuite):
     files = typecheck_files
diff --git a/test-data/unit/check-38.test b/test-data/unit/check-38.test
new file mode 100644
index 000000000000..3a211f311c7d
--- /dev/null
+++ b/test-data/unit/check-38.test
@@ -0,0 +1,21 @@
+[case testScopedIgnore]
+def f(a: int): ...
+f(
+    'BAD'
+)  # type: ignore
+
+[case testMultipleScopedIgnores]
+# flags: --warn-unused-ignores
+def f(a: int): ...
+f(
+    'BAD'  # type: ignore
+)  # type: ignore  # N: unused 'type: ignore' comment
+
+[case testNestedScopedIgnores]
+# flags: --warn-unused-ignores
+def f(a: int) -> int: ...
+f(  # type: ignore  # N: unused 'type: ignore' comment
+    f(
+        'BAD'  # type: ignore
+    )  # type: ignore  # N: unused 'type: ignore' comment
+)  # type: ignore  # N: unused 'type: ignore' comment

From e660a029af0dd1f6d5640631973ec6ee7ab35b66 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Tue, 9 Apr 2019 11:58:09 -0700
Subject: [PATCH 03/12] Trivial code review changes.

---
 mypy/errors.py         | 4 +++-
 mypy/fastparse.py      | 4 +++-
 mypy/nodes.py          | 3 ++-
 mypy/test/testcheck.py | 2 +-
 mypy/treetransform.py  | 2 +-
 5 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/mypy/errors.py b/mypy/errors.py
index a5ef2e01b6d6..f08582b1f05a 100644
--- a/mypy/errors.py
+++ b/mypy/errors.py
@@ -113,7 +113,8 @@ class Errors:
     # Path to current file.
     file = ''  # type: str
 
-    # Ignore errors on these lines of each file.
+    # Ignore errors on these lines of each file. Keys are modules, values are mappings from:
+    # ignored line -> line of "type: ignore" comment it is scoped to within that module.
     ignored_lines = None  # type: Dict[str, Dict[int, int]]
 
     # Lines on which an error was actually ignored.
@@ -300,6 +301,7 @@ def clear_errors_in_targets(self, path: str, targets: Set[str]) -> None:
             self.error_info_map[path] = new_errors
 
     def generate_unused_ignore_notes(self, file: str) -> None:
+        # The values() here are the line numbers of *actual* "type: ignore" comments.
         ignored_lines = set(self.ignored_lines[file].values())
         if not self.is_typeshed_file(file) and file not in self.ignored_files:
             for line in ignored_lines - self.used_ignored_lines[file]:
diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index bc8264510744..4025ff512908 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -251,6 +251,8 @@ def __init__(self,
         self.is_stub = is_stub
         self.errors = errors
 
+        # Lines to ignore when checking. This is a mapping from:
+        # ignored line -> line of "type: ignore" comment it is scoped to.
         self.type_ignores = {}  # type: Dict[int, int]
 
         # Cache of visit_X methods keyed by type of visited object
@@ -272,7 +274,7 @@ def visit(self, node: Optional[AST]) -> Any:
             visitor = getattr(self, method)
             self.visitor_cache[typeobj] = visitor
         result = visitor(node)
-        if (3, 8) < sys.version_info and isinstance(node, ast3.expr):
+        if sys.version_info >= (3, 8) and isinstance(node, ast3.expr):
             self.scope_ignores(node)
         return result
 
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 67b11738cf09..8615377912ee 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -226,7 +226,8 @@ class MypyFile(SymbolNode):
     names = None  # type: SymbolTable
     # All import nodes within the file (also ones within functions etc.)
     imports = None  # type: List[ImportBase]
-    # Lines to ignore when checking
+    # Lines to ignore when checking. This is a mapping from:
+    # ignored line -> line of "type: ignore" comment it is scoped to.
     ignored_lines = None  # type: Dict[int, int]
     # Is this file represented by a stub file (.pyi)?
     is_stub = False
diff --git a/mypy/test/testcheck.py b/mypy/test/testcheck.py
index 26048972524e..385f8b516622 100644
--- a/mypy/test/testcheck.py
+++ b/mypy/test/testcheck.py
@@ -85,7 +85,7 @@
     'check-newsemanal.test',
 ]
 
-if (3, 8) < sys.version_info:
+if sys.version_info >= (3, 8):
     typecheck_files.append('check-38.test')
 
 
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index 0ab7fe89926f..4aca8f35ce5e 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -60,7 +60,7 @@ def __init__(self) -> None:
     def visit_mypy_file(self, node: MypyFile) -> MypyFile:
         # NOTE: The 'names' and 'imports' instance variables will be empty!
         new = MypyFile(self.statements(node.defs), [], node.is_bom,
-                       ignored_lines=node.ignored_lines)
+                       ignored_lines=node.ignored_lines.copy())
         new._fullname = node._fullname
         new.path = node.path
         new.names = SymbolTable()

From 39df3eee510eeefeff185155460096434e02f66e Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Tue, 9 Apr 2019 12:19:37 -0700
Subject: [PATCH 04/12] Add clarifying info to version guards.

---
 mypy/fastparse.py      | 1 +
 mypy/test/testcheck.py | 1 +
 2 files changed, 2 insertions(+)

diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index 4025ff512908..3775139b4068 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -274,6 +274,7 @@ def visit(self, node: Optional[AST]) -> Any:
             visitor = getattr(self, method)
             self.visitor_cache[typeobj] = visitor
         result = visitor(node)
+        # In Python 3.8, we can expand the scope of ignores to a whole expression:
         if sys.version_info >= (3, 8) and isinstance(node, ast3.expr):
             self.scope_ignores(node)
         return result
diff --git a/mypy/test/testcheck.py b/mypy/test/testcheck.py
index 385f8b516622..f201f663cc81 100644
--- a/mypy/test/testcheck.py
+++ b/mypy/test/testcheck.py
@@ -85,6 +85,7 @@
     'check-newsemanal.test',
 ]
 
+# Tests that use Python 3.8-only AST features (like expression-scoped ignores):
 if sys.version_info >= (3, 8):
     typecheck_files.append('check-38.test')
 

From 001c8e5519842866942112ce9cb05b1a5200cc50 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Tue, 9 Apr 2019 17:25:12 -0700
Subject: [PATCH 05/12] Improve test cases.

---
 test-data/unit/check-38.test | 71 +++++++++++++++++++++++++++++++++---
 1 file changed, 66 insertions(+), 5 deletions(-)

diff --git a/test-data/unit/check-38.test b/test-data/unit/check-38.test
index 3a211f311c7d..99ec989751c0 100644
--- a/test-data/unit/check-38.test
+++ b/test-data/unit/check-38.test
@@ -1,17 +1,69 @@
-[case testScopedIgnore]
+[case testIssue1032]
 def f(a: int): ...
 f(
     'BAD'
 )  # type: ignore
 
-[case testMultipleScopedIgnores]
+[case testMultipleScopedIgnores1]
 # flags: --warn-unused-ignores
-def f(a: int): ...
-f(
+(  # type: ignore  # N: unused 'type: ignore' comment
+    'BAD'  # type: ignore
+    +  # type: ignore  # N: unused 'type: ignore' comment
+    0  # type: ignore  # N: unused 'type: ignore' comment
+)  # type: ignore  # N: unused 'type: ignore' comment
+
+[case testMultipleScopedIgnores2]
+# flags: --warn-unused-ignores
+(  # type: ignore  # N: unused 'type: ignore' comment
+    'BAD'
+    -  # type: ignore
+    0  # type: ignore  # N: unused 'type: ignore' comment
+)  # type: ignore  # N: unused 'type: ignore' comment
+
+[case testMultipleScopedIgnores3]
+# flags: --warn-unused-ignores
+(  # type: ignore  # N: unused 'type: ignore' comment
+    'BAD'
+    /
+    0  # type: ignore
+)  # type: ignore  # N: unused 'type: ignore' comment
+
+[case testMultipleScopedIgnoresList]
+# flags: --warn-unused-ignores
+[  # type: ignore  # type: ignore  # N: unused 'type: ignore' comment
     'BAD'  # type: ignore
+    &  # type: ignore  # N: unused 'type: ignore' comment
+    0,  # type: ignore  # N: unused 'type: ignore' comment
+]  # type: ignore  # N: unused 'type: ignore' comment
+[builtins fixtures/list.pyi]
+
+[case testMultipleScopedIgnoresSet]
+# flags: --warn-unused-ignores
+{  # type: ignore  # N: unused 'type: ignore' comment
+    'BAD'
+    |  # type: ignore
+    0,  # type: ignore  # N: unused 'type: ignore' comment
+}  # type: ignore  # N: unused 'type: ignore' comment
+[builtins fixtures/set.pyi]
+
+[case testMultipleScopedIgnoresTuple]
+# flags: --warn-unused-ignores
+(  # type: ignore  # N: unused 'type: ignore' comment
+    'BAD'
+    ^
+    0,  # type: ignore
+)  # type: ignore  # N: unused 'type: ignore' comment
+
+[case testNestedScopedIgnores1]
+# flags: --warn-unused-ignores
+def f(a: int) -> int: ...
+f(  # type: ignore  # N: unused 'type: ignore' comment
+    f(  # type: ignore
+        'BAD'  # type: ignore  # N: unused 'type: ignore' comment
+    )  # type: ignore  # N: unused 'type: ignore' comment
 )  # type: ignore  # N: unused 'type: ignore' comment
 
-[case testNestedScopedIgnores]
+[case testNestedScopedIgnores2]
 # flags: --warn-unused-ignores
 def f(a: int) -> int: ...
 f(  # type: ignore  # N: unused 'type: ignore' comment
@@ -19,3 +71,12 @@ f(  # type: ignore  # N: unused 'type: ignore' comment
         'BAD'  # type: ignore
     )  # type: ignore  # N: unused 'type: ignore' comment
 )  # type: ignore  # N: unused 'type: ignore' comment
+
+[case testNestedScopedIgnores3]
+# flags: --warn-unused-ignores
+def f(a: int) -> int: ...
+f(  # type: ignore  # N: unused 'type: ignore' comment
+    f(
+        'BAD'
+    )  # type: ignore
+)  # type: ignore  # N: unused 'type: ignore' comment

From 57f6e1ab25287a2f0eb530d540aeb318ef0167f1 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Tue, 9 Apr 2019 17:53:09 -0700
Subject: [PATCH 06/12] Refactoring from code review.

---
 mypy/fastparse.py | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index 3775139b4068..daaac571904a 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -251,6 +251,9 @@ def __init__(self,
         self.is_stub = is_stub
         self.errors = errors
 
+        # The line numbers of *actual* "type: ignore" comments:
+        self.type_ignore_comments = set()  # type: Set[int]
+
         # Lines to ignore when checking. This is a mapping from:
         # ignored line -> line of "type: ignore" comment it is scoped to.
         self.type_ignores = {}  # type: Dict[int, int]
@@ -273,20 +276,21 @@ def visit(self, node: Optional[AST]) -> Any:
             method = 'visit_' + node.__class__.__name__
             visitor = getattr(self, method)
             self.visitor_cache[typeobj] = visitor
-        result = visitor(node)
         # In Python 3.8, we can expand the scope of ignores to a whole expression:
         if sys.version_info >= (3, 8) and isinstance(node, ast3.expr):
             self.scope_ignores(node)
-        return result
+        return visitor(node)
 
     def scope_ignores(self, node: ast3.expr) -> None:
         end_lineno = getattr(node, "end_lineno", None)
         if end_lineno is None:
             return
         node_lines = range(node.lineno, end_lineno + 1)
+        # Check to see if this expression overlaps with any "type: ignore" comments.
+        # If so, take the first one and grow its scope to cover the whole node:
         for line in node_lines:
-            if line in self.type_ignores.values():
-                self.type_ignores = {**dict.fromkeys(node_lines, line), **self.type_ignores}
+            if line in self.type_ignore_comments:
+                self.type_ignores.update(dict.fromkeys(node_lines, line))
                 return
 
     def set_line(self, node: N, n: Union[ast3.expr, ast3.stmt]) -> N:
@@ -410,8 +414,9 @@ def translate_module_id(self, id: str) -> str:
         return id
 
     def visit_Module(self, mod: ast3.Module) -> MypyFile:
-        self.type_ignores = {ti.lineno: ti.lineno for ti in mod.type_ignores}
+        self.type_ignore_comments = {ti.lineno for ti in mod.type_ignores}
         body = self.fix_function_overloads(self.translate_stmt_list(mod.body))
+        self.type_ignores.update({line: line for line in self.type_ignore_comments})
         return MypyFile(body,
                         self.imports,
                         False,
@@ -611,7 +616,7 @@ def make_argument(self, arg: ast3.arg, default: Optional[ast3.expr], kind: int,
             elif type_comment is not None:
                 extra_ignore, arg_type = parse_type_comment(type_comment, arg.lineno, self.errors)
                 if extra_ignore:
-                    self.type_ignores[arg.lineno] = arg.lineno
+                    self.type_ignore_comments.add(arg.lineno)
 
         return Argument(Var(arg.arg), arg_type, self.visit(default), kind)
 
@@ -669,7 +674,7 @@ def visit_Assign(self, n: ast3.Assign) -> AssignmentStmt:
         if n.type_comment is not None:
             extra_ignore, typ = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignores[n.lineno] = n.lineno
+                self.type_ignore_comments.add(n.lineno)
         else:
             typ = None
         s = AssignmentStmt(lvalues, rvalue, type=typ, new_syntax=False)
@@ -703,7 +708,7 @@ def visit_For(self, n: ast3.For) -> ForStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignores[n.lineno] = n.lineno
+                self.type_ignore_comments.add(n.lineno)
         else:
             target_type = None
         node = ForStmt(self.visit(n.target),
@@ -718,7 +723,7 @@ def visit_AsyncFor(self, n: ast3.AsyncFor) -> ForStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignores[n.lineno] = n.lineno
+                self.type_ignore_comments.add(n.lineno)
         else:
             target_type = None
         node = ForStmt(self.visit(n.target),
@@ -749,7 +754,7 @@ def visit_With(self, n: ast3.With) -> WithStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignores[n.lineno] = n.lineno
+                self.type_ignore_comments.add(n.lineno)
         else:
             target_type = None
         node = WithStmt([self.visit(i.context_expr) for i in n.items],
@@ -763,7 +768,7 @@ def visit_AsyncWith(self, n: ast3.AsyncWith) -> WithStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignores[n.lineno] = n.lineno
+                self.type_ignore_comments.add(n.lineno)
         else:
             target_type = None
         s = WithStmt([self.visit(i.context_expr) for i in n.items],

From 88b7716a35785e6320f0659b595b4da05549825e Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Tue, 9 Apr 2019 18:03:11 -0700
Subject: [PATCH 07/12] Fix linting error.

---
 mypy/fastparse.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index daaac571904a..ce33aef28912 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -2,7 +2,7 @@
 import sys
 
 from typing import (
-    Tuple, Union, TypeVar, Callable, Sequence, Optional, Any, Dict, cast, List, overload
+    Tuple, Union, TypeVar, Callable, Sequence, Optional, Any, Dict, cast, List, overload, Set,
 )
 MYPY = False
 if MYPY:

From 043a8966e6b33b517b7e9da2cf4f7562ed17ee72 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Wed, 10 Apr 2019 09:47:08 -0700
Subject: [PATCH 08/12] Back out previous implementation.

---
 mypy/errors.py        | 12 +++++-------
 mypy/fastparse.py     | 44 ++++++++++++-------------------------------
 mypy/fastparse2.py    |  4 ++--
 mypy/nodes.py         |  9 ++++-----
 mypy/strconv.py       |  4 ++--
 mypy/treetransform.py |  2 +-
 6 files changed, 26 insertions(+), 49 deletions(-)

diff --git a/mypy/errors.py b/mypy/errors.py
index f08582b1f05a..0053e3ec08c4 100644
--- a/mypy/errors.py
+++ b/mypy/errors.py
@@ -113,9 +113,8 @@ class Errors:
     # Path to current file.
     file = ''  # type: str
 
-    # Ignore errors on these lines of each file. Keys are modules, values are mappings from:
-    # ignored line -> line of "type: ignore" comment it is scoped to within that module.
-    ignored_lines = None  # type: Dict[str, Dict[int, int]]
+    # Ignore errors on these lines of each file.
+    ignored_lines = None  # type: Dict[str, Set[int]]
 
     # Lines on which an error was actually ignored.
     used_ignored_lines = None  # type: Dict[str, Set[int]]
@@ -200,7 +199,7 @@ def set_file(self, file: str,
         self.scope = scope
 
     def set_file_ignored_lines(self, file: str,
-                               ignored_lines: Dict[int, int],
+                               ignored_lines: Set[int],
                                ignore_all: bool = False) -> None:
         self.ignored_lines[file] = ignored_lines
         if ignore_all:
@@ -279,7 +278,7 @@ def add_error_info(self, info: ErrorInfo) -> None:
         if not info.blocker:  # Blockers cannot be ignored
             if file in self.ignored_lines and line in self.ignored_lines[file]:
                 # Annotation requests us to ignore all errors on this line.
-                self.used_ignored_lines[file].add(self.ignored_lines[file][line])
+                self.used_ignored_lines[file].add(line)
                 return
             if file in self.ignored_files:
                 return
@@ -301,8 +300,7 @@ def clear_errors_in_targets(self, path: str, targets: Set[str]) -> None:
             self.error_info_map[path] = new_errors
 
     def generate_unused_ignore_notes(self, file: str) -> None:
-        # The values() here are the line numbers of *actual* "type: ignore" comments.
-        ignored_lines = set(self.ignored_lines[file].values())
+        ignored_lines = self.ignored_lines[file]
         if not self.is_typeshed_file(file) and file not in self.ignored_files:
             for line in ignored_lines - self.used_ignored_lines[file]:
                 # Don't use report since add_error_info will ignore the error!
diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index ce33aef28912..d47e1a97148d 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -2,7 +2,7 @@
 import sys
 
 from typing import (
-    Tuple, Union, TypeVar, Callable, Sequence, Optional, Any, Dict, cast, List, overload, Set,
+    Tuple, Union, TypeVar, Callable, Sequence, Optional, Any, Dict, cast, List, overload
 )
 MYPY = False
 if MYPY:
@@ -171,7 +171,7 @@ def parse(source: Union[str, bytes],
         tree.is_stub = is_stub_file
     except SyntaxError as e:
         errors.report(e.lineno, e.offset, e.msg, blocker=True)
-        tree = MypyFile([], [], False, {})
+        tree = MypyFile([], [], False, set())
 
     if raise_on_error and errors.is_errors():
         errors.raise_error()
@@ -251,12 +251,7 @@ def __init__(self,
         self.is_stub = is_stub
         self.errors = errors
 
-        # The line numbers of *actual* "type: ignore" comments:
-        self.type_ignore_comments = set()  # type: Set[int]
-
-        # Lines to ignore when checking. This is a mapping from:
-        # ignored line -> line of "type: ignore" comment it is scoped to.
-        self.type_ignores = {}  # type: Dict[int, int]
+        self.extra_type_ignores = []  # type: List[int]
 
         # Cache of visit_X methods keyed by type of visited object
         self.visitor_cache = {}  # type: Dict[type, Callable[[Optional[AST]], Any]]
@@ -276,23 +271,8 @@ def visit(self, node: Optional[AST]) -> Any:
             method = 'visit_' + node.__class__.__name__
             visitor = getattr(self, method)
             self.visitor_cache[typeobj] = visitor
-        # In Python 3.8, we can expand the scope of ignores to a whole expression:
-        if sys.version_info >= (3, 8) and isinstance(node, ast3.expr):
-            self.scope_ignores(node)
         return visitor(node)
 
-    def scope_ignores(self, node: ast3.expr) -> None:
-        end_lineno = getattr(node, "end_lineno", None)
-        if end_lineno is None:
-            return
-        node_lines = range(node.lineno, end_lineno + 1)
-        # Check to see if this expression overlaps with any "type: ignore" comments.
-        # If so, take the first one and grow its scope to cover the whole node:
-        for line in node_lines:
-            if line in self.type_ignore_comments:
-                self.type_ignores.update(dict.fromkeys(node_lines, line))
-                return
-
     def set_line(self, node: N, n: Union[ast3.expr, ast3.stmt]) -> N:
         node.line = n.lineno
         node.column = n.col_offset
@@ -414,13 +394,13 @@ def translate_module_id(self, id: str) -> str:
         return id
 
     def visit_Module(self, mod: ast3.Module) -> MypyFile:
-        self.type_ignore_comments = {ti.lineno for ti in mod.type_ignores}
         body = self.fix_function_overloads(self.translate_stmt_list(mod.body))
-        self.type_ignores.update({line: line for line in self.type_ignore_comments})
+        ignores = [ti.lineno for ti in mod.type_ignores]
+        ignores.extend(self.extra_type_ignores)
         return MypyFile(body,
                         self.imports,
                         False,
-                        self.type_ignores,
+                        set(ignores),
                         )
 
     # --- stmt ---
@@ -616,7 +596,7 @@ def make_argument(self, arg: ast3.arg, default: Optional[ast3.expr], kind: int,
             elif type_comment is not None:
                 extra_ignore, arg_type = parse_type_comment(type_comment, arg.lineno, self.errors)
                 if extra_ignore:
-                    self.type_ignore_comments.add(arg.lineno)
+                    self.extra_type_ignores.append(arg.lineno)
 
         return Argument(Var(arg.arg), arg_type, self.visit(default), kind)
 
@@ -674,7 +654,7 @@ def visit_Assign(self, n: ast3.Assign) -> AssignmentStmt:
         if n.type_comment is not None:
             extra_ignore, typ = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignore_comments.add(n.lineno)
+                self.extra_type_ignores.append(n.lineno)
         else:
             typ = None
         s = AssignmentStmt(lvalues, rvalue, type=typ, new_syntax=False)
@@ -708,7 +688,7 @@ def visit_For(self, n: ast3.For) -> ForStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignore_comments.add(n.lineno)
+                self.extra_type_ignores.append(n.lineno)
         else:
             target_type = None
         node = ForStmt(self.visit(n.target),
@@ -723,7 +703,7 @@ def visit_AsyncFor(self, n: ast3.AsyncFor) -> ForStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignore_comments.add(n.lineno)
+                self.extra_type_ignores.append(n.lineno)
         else:
             target_type = None
         node = ForStmt(self.visit(n.target),
@@ -754,7 +734,7 @@ def visit_With(self, n: ast3.With) -> WithStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignore_comments.add(n.lineno)
+                self.extra_type_ignores.append(n.lineno)
         else:
             target_type = None
         node = WithStmt([self.visit(i.context_expr) for i in n.items],
@@ -768,7 +748,7 @@ def visit_AsyncWith(self, n: ast3.AsyncWith) -> WithStmt:
         if n.type_comment is not None:
             extra_ignore, target_type = parse_type_comment(n.type_comment, n.lineno, self.errors)
             if extra_ignore:
-                self.type_ignore_comments.add(n.lineno)
+                self.extra_type_ignores.append(n.lineno)
         else:
             target_type = None
         s = WithStmt([self.visit(i.context_expr) for i in n.items],
diff --git a/mypy/fastparse2.py b/mypy/fastparse2.py
index 66cee7c994da..95f415c629cb 100644
--- a/mypy/fastparse2.py
+++ b/mypy/fastparse2.py
@@ -113,7 +113,7 @@ def parse(source: Union[str, bytes],
         tree.is_stub = is_stub_file
     except SyntaxError as e:
         errors.report(e.lineno, e.offset, e.msg, blocker=True)
-        tree = MypyFile([], [], False, {})
+        tree = MypyFile([], [], False, set())
 
     if raise_on_error and errors.is_errors():
         errors.raise_error()
@@ -308,7 +308,7 @@ def visit_Module(self, mod: ast27.Module) -> MypyFile:
         return MypyFile(body,
                         self.imports,
                         False,
-                        {line: line for line in ignores},
+                        set(ignores),
                         )
 
     # --- stmt ---
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 8615377912ee..06be60b0f6fe 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -226,9 +226,8 @@ class MypyFile(SymbolNode):
     names = None  # type: SymbolTable
     # All import nodes within the file (also ones within functions etc.)
     imports = None  # type: List[ImportBase]
-    # Lines to ignore when checking. This is a mapping from:
-    # ignored line -> line of "type: ignore" comment it is scoped to.
-    ignored_lines = None  # type: Dict[int, int]
+    # Lines to ignore when checking
+    ignored_lines = None  # type: Set[int]
     # Is this file represented by a stub file (.pyi)?
     is_stub = False
     # Is this loaded from the cache and thus missing the actual body of the file?
@@ -244,7 +243,7 @@ def __init__(self,
                  defs: List[Statement],
                  imports: List['ImportBase'],
                  is_bom: bool = False,
-                 ignored_lines: Optional[Dict[int, int]] = None) -> None:
+                 ignored_lines: Optional[Set[int]] = None) -> None:
         super().__init__()
         self.defs = defs
         self.line = 1  # Dummy line number
@@ -255,7 +254,7 @@ def __init__(self,
         if ignored_lines:
             self.ignored_lines = ignored_lines
         else:
-            self.ignored_lines = {}
+            self.ignored_lines = set()
 
     def local_definitions(self) -> Iterator[Definition]:
         """Return all definitions within the module (including nested).
diff --git a/mypy/strconv.py b/mypy/strconv.py
index d47d16cd479c..87f7bd97af71 100644
--- a/mypy/strconv.py
+++ b/mypy/strconv.py
@@ -97,8 +97,8 @@ def visit_mypy_file(self, o: 'mypy.nodes.MypyFile') -> str:
             # case# output in all platforms.
             a.insert(0, o.path.replace(os.sep, '/'))
         if o.ignored_lines:
-            a.append('IgnoredLines(%s)' % ', '.join(
-                str(line) for line in sorted(set(o.ignored_lines.values()))))
+            a.append('IgnoredLines(%s)' % ', '.join(str(line)
+                                                    for line in sorted(o.ignored_lines)))
         return self.dump(a, o)
 
     def visit_import(self, o: 'mypy.nodes.Import') -> str:
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index 4aca8f35ce5e..f4bc96e39db6 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -60,7 +60,7 @@ def __init__(self) -> None:
     def visit_mypy_file(self, node: MypyFile) -> MypyFile:
         # NOTE: The 'names' and 'imports' instance variables will be empty!
         new = MypyFile(self.statements(node.defs), [], node.is_bom,
-                       ignored_lines=node.ignored_lines.copy())
+                       ignored_lines=set(node.ignored_lines))
         new._fullname = node._fullname
         new.path = node.path
         new.names = SymbolTable()

From 019d64043982543501c5c8913fe11eff2024abe6 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Wed, 10 Apr 2019 14:55:04 -0700
Subject: [PATCH 09/12] Add breaking test cases.

---
 test-data/unit/check-38.test | 119 +++++++++++++++++------------------
 1 file changed, 58 insertions(+), 61 deletions(-)

diff --git a/test-data/unit/check-38.test b/test-data/unit/check-38.test
index 99ec989751c0..445bc0c3bc02 100644
--- a/test-data/unit/check-38.test
+++ b/test-data/unit/check-38.test
@@ -1,82 +1,79 @@
-[case testIssue1032]
+[case testIgnoreScopeIssue1032]
 def f(a: int): ...
 f(
-    'BAD'
+    "IGNORE"
 )  # type: ignore
 
-[case testMultipleScopedIgnores1]
+case testIgnoreScopeNested1]
+def f(a: int) -> int: ...
+f(
+    f(
+        "IGNORE"
+    )  # type: ignore
+)
+
+[case testIgnoreScopeNested2]
+[
+    "IGNORE"  # type: ignore
+    &
+    "IGNORE",
+]
+[builtins fixtures/list.pyi]
+
+[case testIgnoreScopeNested3]
+{
+    "IGNORE"
+    |  # type: ignore
+    "IGNORE",
+}
+[builtins fixtures/set.pyi]
+
+[case testIgnoreScopeNested4]
+{
+    "IGNORE"
+    :
+    "IGNORE",  # type: ignore
+}
+[builtins fixtures/dict.pyi]
+
+[case testIgnoreScopeNestedNonOverlapping]
+def f(x: int): ...
+def g(x: int): ...
+(
+    f("ERROR"),  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
+    g("IGNORE"),  # type: ignore
+    f("ERROR"),  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
+)
+
+[case testIgnoreScopeNestedOverlapping]
+def f(x: int): ...
+def g(x: int): ...
+(
+    f("ERROR"), g(  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
+        "IGNORE"  # type: ignore
+    ), f("ERROR"),  # E: Argument 1 to "f" has incompatible type "str"; expected "int"
+)
+
+[case testIgnoreScopeUnused1]
 # flags: --warn-unused-ignores
 (  # type: ignore  # N: unused 'type: ignore' comment
-    'BAD'  # type: ignore
+    "IGNORE"  # type: ignore
     +  # type: ignore  # N: unused 'type: ignore' comment
     0  # type: ignore  # N: unused 'type: ignore' comment
 )  # type: ignore  # N: unused 'type: ignore' comment
 
-[case testMultipleScopedIgnores2]
+[case testIgnoreScopeUnused2]
 # flags: --warn-unused-ignores
 (  # type: ignore  # N: unused 'type: ignore' comment
-    'BAD'
+    "IGNORE"
     -  # type: ignore
     0  # type: ignore  # N: unused 'type: ignore' comment
 )  # type: ignore  # N: unused 'type: ignore' comment
 
-[case testMultipleScopedIgnores3]
+[case testIgnoreScopeUnused3]
 # flags: --warn-unused-ignores
 (  # type: ignore  # N: unused 'type: ignore' comment
-    'BAD'
+    "IGNORE"
     /
     0  # type: ignore
 )  # type: ignore  # N: unused 'type: ignore' comment
-
-[case testMultipleScopedIgnoresList]
-# flags: --warn-unused-ignores
-[  # type: ignore  # type: ignore  # N: unused 'type: ignore' comment
-    'BAD'  # type: ignore
-    &  # type: ignore  # N: unused 'type: ignore' comment
-    0,  # type: ignore  # N: unused 'type: ignore' comment
-]  # type: ignore  # N: unused 'type: ignore' comment
-[builtins fixtures/list.pyi]
-
-[case testMultipleScopedIgnoresSet]
-# flags: --warn-unused-ignores
-{  # type: ignore  # N: unused 'type: ignore' comment
-    'BAD'
-    |  # type: ignore
-    0,  # type: ignore  # N: unused 'type: ignore' comment
-}  # type: ignore  # N: unused 'type: ignore' comment
-[builtins fixtures/set.pyi]
-
-[case testMultipleScopedIgnoresTuple]
-# flags: --warn-unused-ignores
-(  # type: ignore  # N: unused 'type: ignore' comment
-    'BAD'
-    ^
-    0,  # type: ignore
-)  # type: ignore  # N: unused 'type: ignore' comment
-
-[case testNestedScopedIgnores1]
-# flags: --warn-unused-ignores
-def f(a: int) -> int: ...
-f(  # type: ignore  # N: unused 'type: ignore' comment
-    f(  # type: ignore
-        'BAD'  # type: ignore  # N: unused 'type: ignore' comment
-    )  # type: ignore  # N: unused 'type: ignore' comment
-)  # type: ignore  # N: unused 'type: ignore' comment
-
-[case testNestedScopedIgnores2]
-# flags: --warn-unused-ignores
-def f(a: int) -> int: ...
-f(  # type: ignore  # N: unused 'type: ignore' comment
-    f(
-        'BAD'  # type: ignore
-    )  # type: ignore  # N: unused 'type: ignore' comment
-)  # type: ignore  # N: unused 'type: ignore' comment
-
-[case testNestedScopedIgnores3]
-# flags: --warn-unused-ignores
-def f(a: int) -> int: ...
-f(  # type: ignore  # N: unused 'type: ignore' comment
-    f(
-        'BAD'
-    )  # type: ignore
-)  # type: ignore  # N: unused 'type: ignore' comment

From b32317ee4f800b50f4ce63e9f8884996939b2b09 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Wed, 10 Apr 2019 16:46:46 -0700
Subject: [PATCH 10/12] Fix broken tests.

---
 test-data/unit/check-38.test | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/test-data/unit/check-38.test b/test-data/unit/check-38.test
index 445bc0c3bc02..c4c9a154f661 100644
--- a/test-data/unit/check-38.test
+++ b/test-data/unit/check-38.test
@@ -4,7 +4,7 @@ f(
     "IGNORE"
 )  # type: ignore
 
-case testIgnoreScopeNested1]
+[case testIgnoreScopeNested1]
 def f(a: int) -> int: ...
 f(
     f(
@@ -30,8 +30,8 @@ f(
 
 [case testIgnoreScopeNested4]
 {
-    "IGNORE"
-    :
+    None: "IGNORE"
+    ^
     "IGNORE",  # type: ignore
 }
 [builtins fixtures/dict.pyi]

From 8436257b40ee16f46b9673174ab0bf76c62de39f Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Wed, 10 Apr 2019 17:11:58 -0700
Subject: [PATCH 11/12] New implementation of expression-scoped ignores.

---
 mypy/errors.py    | 37 ++++++++++++++++++++++++++-----------
 mypy/fastparse.py |  1 +
 mypy/messages.py  |  9 ++++++++-
 mypy/nodes.py     |  4 +++-
 4 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/mypy/errors.py b/mypy/errors.py
index 0053e3ec08c4..d2b482b33ef9 100644
--- a/mypy/errors.py
+++ b/mypy/errors.py
@@ -54,8 +54,9 @@ class ErrorInfo:
     # Only report this particular messages once per program.
     only_once = False
 
-    # Actual origin of the error message as tuple (path, line number)
-    origin = None  # type: Tuple[str, int]
+    # Actual origin of the error message as tuple (path, line number, end line number)
+    # If end line number is unknown, use line number.
+    origin = None  # type: Tuple[str, int, int]
 
     # Fine-grained incremental target where this was reported
     target = None  # type: Optional[str]
@@ -72,7 +73,7 @@ def __init__(self,
                  message: str,
                  blocker: bool,
                  only_once: bool,
-                 origin: Optional[Tuple[str, int]] = None,
+                 origin: Optional[Tuple[str, int, int]] = None,
                  target: Optional[str] = None) -> None:
         self.import_ctx = import_ctx
         self.file = file
@@ -85,7 +86,7 @@ def __init__(self,
         self.message = message
         self.blocker = blocker
         self.only_once = only_once
-        self.origin = origin or (file, line)
+        self.origin = origin or (file, line, line)
         self.target = target
 
 
@@ -233,7 +234,8 @@ def report(self,
                file: Optional[str] = None,
                only_once: bool = False,
                origin_line: Optional[int] = None,
-               offset: int = 0) -> None:
+               offset: int = 0,
+               end_line: Optional[int] = None) -> None:
         """Report message at the given line using the current error context.
 
         Args:
@@ -244,6 +246,7 @@ def report(self,
             file: if non-None, override current file as context
             only_once: if True, only report this exact message once per build
             origin_line: if non-None, override current context as origin
+            end_line: if non-None, override current context as end
         """
         if self.scope:
             type = self.scope.current_type_name()
@@ -260,10 +263,17 @@ def report(self,
             file = self.file
         if offset:
             message = " " * offset + message
+
+        if origin_line is None:
+            origin_line = line
+
+        if end_line is None:
+            end_line = origin_line
+
         info = ErrorInfo(self.import_context(), file, self.current_module(), type,
                          function, line, column, severity, message,
                          blocker, only_once,
-                         origin=(self.file, origin_line) if origin_line else None,
+                         origin=(self.file, origin_line, end_line),
                          target=self.current_target())
         self.add_error_info(info)
 
@@ -274,12 +284,17 @@ def _add_error_info(self, file: str, info: ErrorInfo) -> None:
         self.error_info_map[file].append(info)
 
     def add_error_info(self, info: ErrorInfo) -> None:
-        file, line = info.origin
+        file, line, end_line = info.origin
         if not info.blocker:  # Blockers cannot be ignored
-            if file in self.ignored_lines and line in self.ignored_lines[file]:
-                # Annotation requests us to ignore all errors on this line.
-                self.used_ignored_lines[file].add(line)
-                return
+            if file in self.ignored_lines:
+                # Check each line in this context for "type: ignore" comments.
+                # For anything other than Python 3.8 expressions, line == end_line,
+                # so we only loop once.
+                for scope_line in range(line, end_line + 1):
+                    if scope_line in self.ignored_lines[file]:
+                        # Annotation requests us to ignore all errors on this line.
+                        self.used_ignored_lines[file].add(scope_line)
+                        return
             if file in self.ignored_files:
                 return
         if info.only_once:
diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index d47e1a97148d..c788ab8932fa 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -276,6 +276,7 @@ def visit(self, node: Optional[AST]) -> Any:
     def set_line(self, node: N, n: Union[ast3.expr, ast3.stmt]) -> N:
         node.line = n.lineno
         node.column = n.col_offset
+        node.end_line = getattr(n, "end_lineno", None)
         return node
 
     def translate_expr_list(self, l: Sequence[AST]) -> List[Expression]:
diff --git a/mypy/messages.py b/mypy/messages.py
index 80c5eaa665ec..8698154eba0c 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -111,11 +111,18 @@ def report(self, msg: str, context: Optional[Context], severity: str,
                file: Optional[str] = None, origin: Optional[Context] = None,
                offset: int = 0) -> None:
         """Report an error or note (unless disabled)."""
+        if origin is not None:
+            end_line = origin.end_line
+        elif context is not None:
+            end_line = context.end_line
+        else:
+            end_line = None
         if self.disable_count <= 0:
             self.errors.report(context.get_line() if context else -1,
                                context.get_column() if context else -1,
                                msg, severity=severity, file=file, offset=offset,
-                               origin_line=origin.get_line() if origin else None)
+                               origin_line=origin.get_line() if origin else None,
+                               end_line=end_line)
 
     def fail(self, msg: str, context: Optional[Context], file: Optional[str] = None,
              origin: Optional[Context] = None) -> None:
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 06be60b0f6fe..e6d217a8f014 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -22,11 +22,12 @@
 
 class Context:
     """Base type for objects that are valid as error message locations."""
-    __slots__ = ('line', 'column')
+    __slots__ = ('line', 'column', 'end_line')
 
     def __init__(self, line: int = -1, column: int = -1) -> None:
         self.line = line
         self.column = column
+        self.end_line = None  # type: Optional[int]
 
     def set_line(self, target: Union['Context', int], column: Optional[int] = None) -> None:
         """If target is a node, pull line (and column) information
@@ -38,6 +39,7 @@ def set_line(self, target: Union['Context', int], column: Optional[int] = None)
         else:
             self.line = target.line
             self.column = target.column
+            self.end_line = target.end_line
 
         if column is not None:
             self.column = column

From 08ab70492fc442bab163473044ccb3341a924d5e Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Wed, 10 Apr 2019 18:06:53 -0700
Subject: [PATCH 12/12] Don't copy end_lineno info for statements.

---
 mypy/fastparse.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index c788ab8932fa..c2366dd71fbc 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -276,7 +276,7 @@ def visit(self, node: Optional[AST]) -> Any:
     def set_line(self, node: N, n: Union[ast3.expr, ast3.stmt]) -> N:
         node.line = n.lineno
         node.column = n.col_offset
-        node.end_line = getattr(n, "end_lineno", None)
+        node.end_line = getattr(n, "end_lineno", None) if isinstance(n, ast3.expr) else None
         return node
 
     def translate_expr_list(self, l: Sequence[AST]) -> List[Expression]: