diff --git a/pyproject.toml b/pyproject.toml
index ac4e78d00cb..00819320f70 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -97,6 +97,7 @@ force-exclude = '''
 [tool.mypy]
 check_untyped_defs = true
 ignore_missing_imports = true
+show_error_codes = true
 warn_redundant_casts = true
 warn_unused_configs = true
 warn_unused_ignores = true
@@ -113,29 +114,7 @@ module = [
   'poetry.config.file_config_source',
   'poetry.console.application',
   'poetry.console.logging.formatters.builder_formatter',
-  'poetry.console.commands.add',
-  'poetry.console.commands.build',
-  'poetry.console.commands.cache.clear',
-  'poetry.console.commands.command',
-  'poetry.console.commands.config',
-  'poetry.console.commands.debug.resolve',
-  'poetry.console.commands.end',
-  'poetry.console.commands.env_command',
-  'poetry.console.commands.export',
   'poetry.console.commands.init',
-  'poetry.console.commands.installer_command',
-  'poetry.console.commands.install',
-  'poetry.console.commands.lock',
-  'poetry.console.commands.new',
-  'poetry.console.commands.plugin.add',
-  'poetry.console.commands.remove',
-  'poetry.console.commands.run',
-  'poetry.console.commands.self.update',
-  'poetry.console.commands.shell',
-  'poetry.console.commands.show',
-  'poetry.console.commands.source.add',
-  'poetry.console.commands.update',
-  'poetry.console.commands.version',
   'poetry.inspection.info',
   'poetry.installation.chef',
   'poetry.installation.chooser',
diff --git a/src/poetry/console/commands/add.py b/src/poetry/console/commands/add.py
index 67c51320e0c..d0e734a1587 100644
--- a/src/poetry/console/commands/add.py
+++ b/src/poetry/console/commands/add.py
@@ -2,6 +2,7 @@
 
 from typing import Dict
 from typing import List
+from typing import cast
 
 from cleo.helpers import argument
 from cleo.helpers import option
@@ -236,7 +237,7 @@ def handle(self) -> int:
         if self.option("lock"):
             self._installer.lock()
 
-        self._installer.whitelist([r["name"] for r in requirements])
+        self._installer.whitelist([cast(str, r["name"]) for r in requirements])
 
         status = self._installer.run()
 
diff --git a/src/poetry/console/commands/cache/clear.py b/src/poetry/console/commands/cache/clear.py
index 73f9a612f00..dee6a838e18 100644
--- a/src/poetry/console/commands/cache/clear.py
+++ b/src/poetry/console/commands/cache/clear.py
@@ -79,3 +79,5 @@ def handle(self) -> int:
             cache.forget(f"{package}:{version}")
         else:
             raise ValueError("Invalid cache key")
+
+        return 0
diff --git a/src/poetry/console/commands/command.py b/src/poetry/console/commands/command.py
index a717fa4e666..a812311931e 100644
--- a/src/poetry/console/commands/command.py
+++ b/src/poetry/console/commands/command.py
@@ -1,4 +1,5 @@
 from typing import TYPE_CHECKING
+from typing import List
 from typing import Optional
 
 from cleo.commands.command import Command as BaseCommand
@@ -10,7 +11,7 @@
 
 
 class Command(BaseCommand):
-    loggers = []
+    loggers: List[str] = []
 
     _poetry: Optional["Poetry"] = None
 
diff --git a/src/poetry/console/commands/config.py b/src/poetry/console/commands/config.py
index 785abe361fe..5dcc4c39acb 100644
--- a/src/poetry/console/commands/config.py
+++ b/src/poetry/console/commands/config.py
@@ -7,6 +7,8 @@
 from typing import List
 from typing import Optional
 from typing import Tuple
+from typing import Union
+from typing import cast
 
 from cleo.helpers import argument
 from cleo.helpers import option
@@ -144,6 +146,7 @@ def handle(self) -> Optional[int]:
         # show the value if no value is provided
         if not self.argument("value") and not self.option("unset"):
             m = re.match(r"^repos?(?:itories)?(?:\.(.+))?", self.argument("key"))
+            value: Union[str, Dict[str, Any]]
             if m:
                 if not m.group(1):
                     value = {}
@@ -158,8 +161,7 @@ def handle(self) -> Optional[int]:
 
                 self.line(str(value))
             else:
-                values = self.unique_config_values
-                if setting_key not in values:
+                if setting_key not in self.unique_config_values:
                     raise ValueError(f"There is no {setting_key} setting.")
 
                 value = config.get(setting_key)
@@ -171,7 +173,7 @@ def handle(self) -> Optional[int]:
 
             return 0
 
-        values = self.argument("value")
+        values: List[str] = self.argument("value")
 
         unique_config_values = self.unique_config_values
         if setting_key in unique_config_values:
@@ -297,7 +299,9 @@ def _handle_single_value(
 
         return 0
 
-    def _list_configuration(self, config: Dict, raw: Dict, k: str = "") -> None:
+    def _list_configuration(
+        self, config: Dict[str, Any], raw: Dict[str, Any], k: str = ""
+    ) -> None:
         orig_k = k
         for key, value in sorted(config.items()):
             if k + key in self.LIST_PROHIBITED_SETTINGS:
@@ -307,7 +311,7 @@ def _list_configuration(self, config: Dict, raw: Dict, k: str = "") -> None:
 
             if isinstance(value, dict):
                 k += f"{key}."
-                self._list_configuration(value, raw_val, k=k)
+                self._list_configuration(value, cast(dict, raw_val), k=k)
                 k = orig_k
 
                 continue
@@ -356,7 +360,7 @@ def _get_setting(
                         setting = ".".join(setting.split(".")[1:])
 
                     values += self._get_setting(
-                        value, k=k, setting=setting, default=default
+                        cast(dict, value), k=k, setting=setting, default=default
                     )
                     k = orig_k
 
diff --git a/src/poetry/console/commands/debug/resolve.py b/src/poetry/console/commands/debug/resolve.py
index 07573229fa0..cb2948b0f8d 100644
--- a/src/poetry/console/commands/debug/resolve.py
+++ b/src/poetry/console/commands/debug/resolve.py
@@ -1,5 +1,4 @@
 from typing import TYPE_CHECKING
-from typing import Optional
 
 from cleo.helpers import argument
 from cleo.helpers import option
@@ -35,7 +34,7 @@ class DebugResolveCommand(InitCommand):
 
     loggers = ["poetry.repositories.pypi_repository", "poetry.inspection.info"]
 
-    def handle(self) -> Optional[int]:
+    def handle(self) -> int:
         from cleo.io.null_io import NullIO
         from poetry.core.packages.project_package import ProjectPackage
 
@@ -143,4 +142,4 @@ def handle(self) -> Optional[int]:
         table.set_rows(rows)
         table.render()
 
-        return None
+        return 0
diff --git a/src/poetry/console/commands/env_command.py b/src/poetry/console/commands/env_command.py
index 5e48ba02c0d..938262ca29a 100644
--- a/src/poetry/console/commands/env_command.py
+++ b/src/poetry/console/commands/env_command.py
@@ -1,5 +1,4 @@
 from typing import TYPE_CHECKING
-from typing import Optional
 
 from poetry.console.commands.command import Command
 
@@ -10,12 +9,13 @@
 
 class EnvCommand(Command):
     def __init__(self) -> None:
-        self._env = None
+        # Set in poetry.console.application.Application.configure_installer
+        self._env: "Env" = None  # type: ignore[assignment]
 
         super().__init__()
 
     @property
-    def env(self) -> Optional["Env"]:
+    def env(self) -> "Env":
         return self._env
 
     def set_env(self, env: "Env") -> None:
diff --git a/src/poetry/console/commands/export.py b/src/poetry/console/commands/export.py
index 508502d84f6..d724888e458 100644
--- a/src/poetry/console/commands/export.py
+++ b/src/poetry/console/commands/export.py
@@ -48,11 +48,11 @@ def handle(self) -> None:
             self.line_error("<comment>The lock file does not exist. Locking.</comment>")
             options = []
             if self.io.is_debug():
-                options.append(("-vvv", None))
+                options.append("-vvv")
             elif self.io.is_very_verbose():
-                options.append(("-vv", None))
+                options.append("-vv")
             elif self.io.is_verbose():
-                options.append(("-v", None))
+                options.append("-v")
 
             self.call("lock", " ".join(options))
 
diff --git a/src/poetry/console/commands/init.py b/src/poetry/console/commands/init.py
index 5d831c1914a..c91772620b8 100644
--- a/src/poetry/console/commands/init.py
+++ b/src/poetry/console/commands/init.py
@@ -5,6 +5,7 @@
 
 from pathlib import Path
 from typing import TYPE_CHECKING
+from typing import Any
 from typing import Dict
 from typing import List
 from typing import Mapping
@@ -20,6 +21,8 @@
 
 
 if TYPE_CHECKING:
+    from tomlkit.items import InlineTable
+
     from poetry.repositories import Pool
 
 
@@ -61,7 +64,7 @@ class InitCommand(Command):
     def __init__(self) -> None:
         super().__init__()
 
-        self._pool = None
+        self._pool: Optional["Pool"] = None
 
     def handle(self) -> int:
         from pathlib import Path
@@ -192,7 +195,7 @@ def handle(self) -> int:
             if self.io.is_interactive():
                 self.line("")
 
-        dev_requirements = {}
+        dev_requirements: Dict[str, str] = {}
         if self.option("dev-dependency"):
             dev_requirements = self._format_requirements(
                 self._determine_requirements(self.option("dev-dependency"))
@@ -237,6 +240,8 @@ def handle(self) -> int:
         with (Path.cwd() / "pyproject.toml").open("w", encoding="utf-8") as f:
             f.write(content)
 
+        return 0
+
     def _determine_requirements(
         self,
         requires: List[str],
@@ -385,7 +390,7 @@ def _find_best_version_for_package(
 
         return package.pretty_name, selector.find_recommended_require_version(package)
 
-    def _parse_requirements(self, requirements: List[str]) -> List[Dict[str, str]]:
+    def _parse_requirements(self, requirements: List[str]) -> List[Dict[str, Any]]:
         from poetry.core.pyproject.exceptions import PyProjectException
 
         from poetry.puzzle.provider import Provider
@@ -476,7 +481,7 @@ def _parse_requirements(self, requirements: List[str]) -> List[Dict[str, str]]:
             )
             pair = pair.strip()
 
-            require = {}
+            require: Dict[str, str] = {}
             if " " in pair:
                 name, version = pair.split(" ", 2)
                 extras_m = re.search(r"\[([\w\d,-_]+)\]$", name)
@@ -521,6 +526,7 @@ def _format_requirements(
         requires = {}
         for requirement in requirements:
             name = requirement.pop("name")
+            constraint: Union[str, "InlineTable"]
             if "version" in requirement and len(requirement) == 1:
                 constraint = requirement["version"]
             else:
diff --git a/src/poetry/console/commands/installer_command.py b/src/poetry/console/commands/installer_command.py
index 2ad333f7d0b..0114b3fd1b7 100644
--- a/src/poetry/console/commands/installer_command.py
+++ b/src/poetry/console/commands/installer_command.py
@@ -1,5 +1,4 @@
 from typing import TYPE_CHECKING
-from typing import Optional
 
 from poetry.console.commands.env_command import EnvCommand
 
@@ -10,7 +9,8 @@
 
 class InstallerCommand(EnvCommand):
     def __init__(self) -> None:
-        self._installer: Optional["Installer"] = None
+        # Set in poetry.console.application.Application.configure_installer
+        self._installer: "Installer" = None  # type: ignore[assignment]
 
         super().__init__()
 
diff --git a/src/poetry/console/commands/new.py b/src/poetry/console/commands/new.py
index 33e141ec740..87bfe966d74 100644
--- a/src/poetry/console/commands/new.py
+++ b/src/poetry/console/commands/new.py
@@ -34,9 +34,9 @@ def handle(self) -> None:
         from poetry.utils.env import SystemEnv
 
         if self.option("src"):
-            layout_ = layout("src")
+            layout_cls = layout("src")
         else:
-            layout_ = layout("standard")
+            layout_cls = layout("standard")
 
         path = Path(self.argument("path"))
         if not path.is_absolute():
@@ -67,7 +67,7 @@ def handle(self) -> None:
         current_env = SystemEnv(Path(sys.executable))
         default_python = "^" + ".".join(str(v) for v in current_env.version_info[:2])
 
-        layout_ = layout_(
+        layout_ = layout_cls(
             name,
             "0.1.0",
             author=author,
diff --git a/src/poetry/console/commands/plugin/add.py b/src/poetry/console/commands/plugin/add.py
index 98142be95ef..6a9b69e2440 100644
--- a/src/poetry/console/commands/plugin/add.py
+++ b/src/poetry/console/commands/plugin/add.py
@@ -115,13 +115,16 @@ def handle(self) -> int:
 
                 break
 
-        root_package.python_versions = ".".join(
+        root_package.python_versions = ".".join(  # type: ignore[union-attr]
             str(v) for v in system_env.version_info[:3]
         )
         # We create a `pyproject.toml` file based on all the information
         # we have about the current environment.
         if not env_dir.joinpath("pyproject.toml").exists():
-            Factory.create_pyproject_from_package(root_package, env_dir)
+            Factory.create_pyproject_from_package(
+                root_package,  # type: ignore[arg-type]
+                env_dir,
+            )
 
         # We add the plugins to the dependencies section of the previously
         # created `pyproject.toml` file
diff --git a/src/poetry/console/commands/remove.py b/src/poetry/console/commands/remove.py
index f1c4dc14db9..772ccc99f48 100644
--- a/src/poetry/console/commands/remove.py
+++ b/src/poetry/console/commands/remove.py
@@ -83,8 +83,8 @@ def handle(self) -> int:
         if "group" in poetry_content and not poetry_content["group"]:
             del poetry_content["group"]
 
-        removed = set(removed)
-        not_found = set(packages).difference(removed)
+        removed_set = set(removed)
+        not_found = set(packages).difference(removed_set)
         if not_found:
             raise ValueError(
                 "The following packages were not found: " + ", ".join(sorted(not_found))
@@ -104,7 +104,7 @@ def handle(self) -> int:
         self._installer.dry_run(self.option("dry-run"))
         self._installer.verbose(self._io.is_verbose())
         self._installer.update(True)
-        self._installer.whitelist(removed)
+        self._installer.whitelist(removed_set)
 
         status = self._installer.run()
 
diff --git a/src/poetry/console/commands/run.py b/src/poetry/console/commands/run.py
index cba38a1e584..9a02e375125 100644
--- a/src/poetry/console/commands/run.py
+++ b/src/poetry/console/commands/run.py
@@ -1,5 +1,6 @@
 from typing import TYPE_CHECKING
 from typing import Any
+from typing import Dict
 from typing import Union
 
 from cleo.helpers import argument
@@ -41,7 +42,7 @@ def _module(self) -> "Module":
 
         return module
 
-    def run_script(self, script: Union[str, dict], args: str) -> Any:
+    def run_script(self, script: Union[str, Dict[str, str]], args: str) -> Any:
         if isinstance(script, dict):
             script = script["callable"]
 
diff --git a/src/poetry/console/commands/self/update.py b/src/poetry/console/commands/self/update.py
index 41e07355306..6e39fa16f82 100644
--- a/src/poetry/console/commands/self/update.py
+++ b/src/poetry/console/commands/self/update.py
@@ -57,8 +57,9 @@ def bin_dir(self) -> Path:
 
         from poetry.utils._compat import WINDOWS
 
-        if os.getenv("POETRY_HOME"):
-            return Path(os.getenv("POETRY_HOME"), "bin").expanduser()
+        home = os.getenv("POETRY_HOME")
+        if home:
+            return Path(home, "bin").expanduser()
 
         user_base = site.getuserbase()
 
@@ -102,13 +103,12 @@ def handle(self) -> int:
             self.line("No release found for the specified version")
             return 1
 
-        packages.sort(
-            key=cmp_to_key(
-                lambda x, y: 0
-                if x.version == y.version
-                else int(x.version < y.version or -1)
-            )
-        )
+        def cmp(x: "Package", y: "Package") -> int:
+            if x.version == y.version:
+                return 0
+            return int(x.version < y.version or -1)
+
+        packages.sort(key=cmp_to_key(cmp))
 
         release = None
         for package in packages:
diff --git a/src/poetry/console/commands/shell.py b/src/poetry/console/commands/shell.py
index 3572d361964..177c1792a8c 100644
--- a/src/poetry/console/commands/shell.py
+++ b/src/poetry/console/commands/shell.py
@@ -35,5 +35,5 @@ def handle(self) -> None:
         # Setting this to avoid spawning unnecessary nested shells
         environ["POETRY_ACTIVE"] = "1"
         shell = Shell.get()
-        shell.activate(self.env)
+        shell.activate(self.env)  # type: ignore[arg-type]
         environ.pop("POETRY_ACTIVE")
diff --git a/src/poetry/console/commands/source/add.py b/src/poetry/console/commands/source/add.py
index 373221dd679..f0135714815 100644
--- a/src/poetry/console/commands/source/add.py
+++ b/src/poetry/console/commands/source/add.py
@@ -64,7 +64,7 @@ def handle(self) -> Optional[int]:
             )
             return 1
 
-        new_source = Source(
+        new_source: Optional[Source] = Source(
             name=name, url=url, default=is_default, secondary=is_secondary
         )
         existing_sources = self.poetry.get_sources()
@@ -86,7 +86,7 @@ def handle(self) -> Optional[int]:
                 )
                 return 1
 
-            if source.name == name:
+            if new_source and source.name == name:
                 self.line(f"Source with name <c1>{name}</c1> already exists. Updating.")
                 source = new_source
                 new_source = None
diff --git a/src/poetry/console/commands/version.py b/src/poetry/console/commands/version.py
index 2aa96ce1aee..944104860c9 100644
--- a/src/poetry/console/commands/version.py
+++ b/src/poetry/console/commands/version.py
@@ -80,27 +80,27 @@ def increment_version(self, version: str, rule: str) -> "Version":
         from poetry.core.semver.version import Version
 
         try:
-            version = Version.parse(version)
+            parsed = Version.parse(version)
         except ValueError:
             raise ValueError("The project's version doesn't seem to follow semver")
 
         if rule in {"major", "premajor"}:
-            new = version.next_major()
+            new = parsed.next_major()
             if rule == "premajor":
                 new = new.first_prerelease()
         elif rule in {"minor", "preminor"}:
-            new = version.next_minor()
+            new = parsed.next_minor()
             if rule == "preminor":
                 new = new.first_prerelease()
         elif rule in {"patch", "prepatch"}:
-            new = version.next_patch()
+            new = parsed.next_patch()
             if rule == "prepatch":
                 new = new.first_prerelease()
         elif rule == "prerelease":
-            if version.is_unstable():
-                new = Version(version.epoch, version.release, version.pre.next())
+            if parsed.is_unstable():
+                new = Version(parsed.epoch, parsed.release, parsed.pre.next())
             else:
-                new = version.next_patch().first_prerelease()
+                new = parsed.next_patch().first_prerelease()
         else:
             new = Version.parse(rule)