diff --git a/crates/ruff_linter/src/checkers/ast/analyze/expression.rs b/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
index f02fe6670a40a..7b0c2f7e0144d 100644
--- a/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
@@ -319,7 +319,7 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                 numpy::rules::numpy_2_0_deprecation(checker, expr);
             }
             if checker.enabled(Rule::DeprecatedMockImport) {
-                pyupgrade::rules::deprecated_mock_attribute(checker, expr);
+                pyupgrade::rules::deprecated_mock_attribute(checker, attribute);
             }
             if checker.enabled(Rule::SixPY3) {
                 flake8_2020::rules::name_or_attribute(checker, expr);
@@ -976,7 +976,6 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             if checker.enabled(Rule::UnsortedDunderAll) {
                 ruff::rules::sort_dunder_all_extend_call(checker, call);
             }
-
             if checker.enabled(Rule::DefaultFactoryKwarg) {
                 ruff::rules::default_factory_kwarg(checker, call);
             }
diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index d13a7a9270c0b..96a00417a503f 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -349,13 +349,6 @@ where
             }
         }
 
-        // Track each top-level import, to guide import insertions.
-        if matches!(stmt, Stmt::Import(_) | Stmt::ImportFrom(_)) {
-            if self.semantic.at_top_level() {
-                self.importer.visit_import(stmt);
-            }
-        }
-
         // Store the flags prior to any further descent, so that we can restore them after visiting
         // the node.
         let flags_snapshot = self.semantic.flags;
@@ -371,14 +364,22 @@ where
                 self.handle_node_load(target);
             }
             Stmt::Import(ast::StmtImport { names, range: _ }) => {
+                if self.semantic.at_top_level() {
+                    self.importer.visit_import(stmt);
+                }
+
                 for alias in names {
-                    if alias.name.contains('.') && alias.asname.is_none() {
-                        // Given `import foo.bar`, `name` would be "foo", and `qualified_name` would be
-                        // "foo.bar".
-                        let name = alias.name.split('.').next().unwrap();
+                    // Given `import foo.bar`, `module` would be "foo", and `call_path` would be
+                    // `["foo", "bar"]`.
+                    let module = alias.name.split('.').next().unwrap();
+
+                    // Mark the top-level module as "seen" by the semantic model.
+                    self.semantic.see(module);
+
+                    if alias.asname.is_none() && alias.name.contains('.') {
                         let call_path: Box<[&str]> = alias.name.split('.').collect();
                         self.add_binding(
-                            name,
+                            module,
                             alias.identifier(),
                             BindingKind::SubmoduleImport(SubmoduleImport { call_path }),
                             BindingFlags::EXTERNAL,
@@ -413,8 +414,20 @@ where
                 level,
                 range: _,
             }) => {
+                if self.semantic.at_top_level() {
+                    self.importer.visit_import(stmt);
+                }
+
                 let module = module.as_deref();
                 let level = *level;
+
+                // Mark the top-level module as "seen" by the semantic model.
+                if level.map_or(true, |level| level == 0) {
+                    if let Some(module) = module.and_then(|module| module.split('.').next()) {
+                        self.semantic.see(module);
+                    }
+                }
+
                 for alias in names {
                     if let Some("__future__") = module {
                         let name = alias.asname.as_ref().unwrap_or(&alias.name);
diff --git a/crates/ruff_linter/src/rules/flake8_2020/rules/name_or_attribute.rs b/crates/ruff_linter/src/rules/flake8_2020/rules/name_or_attribute.rs
index bdd1a7d452660..5913151bcf268 100644
--- a/crates/ruff_linter/src/rules/flake8_2020/rules/name_or_attribute.rs
+++ b/crates/ruff_linter/src/rules/flake8_2020/rules/name_or_attribute.rs
@@ -1,7 +1,7 @@
-use ruff_python_ast::Expr;
-
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -47,6 +47,10 @@ impl Violation for SixPY3 {
 
 /// YTT202
 pub(crate) fn name_or_attribute(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::SIX) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/flake8_async/rules/blocking_os_call.rs b/crates/ruff_linter/src/rules/flake8_async/rules/blocking_os_call.rs
index f5d86c0793910..19c15255e7f1c 100644
--- a/crates/ruff_linter/src/rules/flake8_async/rules/blocking_os_call.rs
+++ b/crates/ruff_linter/src/rules/flake8_async/rules/blocking_os_call.rs
@@ -3,6 +3,7 @@ use ruff_python_ast::ExprCall;
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::call_path::CallPath;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -42,17 +43,19 @@ impl Violation for BlockingOsCallInAsyncFunction {
 
 /// ASYNC102
 pub(crate) fn blocking_os_call(checker: &mut Checker, call: &ExprCall) {
-    if checker.semantic().in_async_context() {
-        if checker
-            .semantic()
-            .resolve_call_path(call.func.as_ref())
-            .as_ref()
-            .is_some_and(is_unsafe_os_method)
-        {
-            checker.diagnostics.push(Diagnostic::new(
-                BlockingOsCallInAsyncFunction,
-                call.func.range(),
-            ));
+    if checker.semantic().seen(Modules::OS) {
+        if checker.semantic().in_async_context() {
+            if checker
+                .semantic()
+                .resolve_call_path(call.func.as_ref())
+                .as_ref()
+                .is_some_and(is_unsafe_os_method)
+            {
+                checker.diagnostics.push(Diagnostic::new(
+                    BlockingOsCallInAsyncFunction,
+                    call.func.range(),
+                ));
+            }
         }
     }
 }
diff --git a/crates/ruff_linter/src/rules/flake8_bandit/rules/bad_file_permissions.rs b/crates/ruff_linter/src/rules/flake8_bandit/rules/bad_file_permissions.rs
index 4bc6da38c1aad..0675e2da0ad3f 100644
--- a/crates/ruff_linter/src/rules/flake8_bandit/rules/bad_file_permissions.rs
+++ b/crates/ruff_linter/src/rules/flake8_bandit/rules/bad_file_permissions.rs
@@ -4,7 +4,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::call_path::CallPath;
 use ruff_python_ast::{self as ast, Expr, Operator};
-use ruff_python_semantic::SemanticModel;
+use ruff_python_semantic::{Modules, SemanticModel};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -60,6 +60,10 @@ enum Reason {
 
 /// S103
 pub(crate) fn bad_file_permissions(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::OS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_bandit/rules/django_raw_sql.rs b/crates/ruff_linter/src/rules/flake8_bandit/rules/django_raw_sql.rs
index 1491894d5b3ee..e5d58b123d669 100644
--- a/crates/ruff_linter/src/rules/flake8_bandit/rules/django_raw_sql.rs
+++ b/crates/ruff_linter/src/rules/flake8_bandit/rules/django_raw_sql.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -35,6 +36,10 @@ impl Violation for DjangoRawSql {
 
 /// S611
 pub(crate) fn django_raw_sql(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_bandit/rules/logging_config_insecure_listen.rs b/crates/ruff_linter/src/rules/flake8_bandit/rules/logging_config_insecure_listen.rs
index 69814c123dae5..9351ae5d2b78c 100644
--- a/crates/ruff_linter/src/rules/flake8_bandit/rules/logging_config_insecure_listen.rs
+++ b/crates/ruff_linter/src/rules/flake8_bandit/rules/logging_config_insecure_listen.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -35,6 +36,10 @@ impl Violation for LoggingConfigInsecureListen {
 
 /// S612
 pub(crate) fn logging_config_insecure_listen(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::LOGGING) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_bandit/rules/tarfile_unsafe_members.rs b/crates/ruff_linter/src/rules/flake8_bandit/rules/tarfile_unsafe_members.rs
index b70083c8533c4..978ae26051ee2 100644
--- a/crates/ruff_linter/src/rules/flake8_bandit/rules/tarfile_unsafe_members.rs
+++ b/crates/ruff_linter/src/rules/flake8_bandit/rules/tarfile_unsafe_members.rs
@@ -3,6 +3,7 @@ use ruff_diagnostics::Diagnostic;
 use ruff_diagnostics::Violation;
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 /// ## What it does
@@ -48,6 +49,10 @@ impl Violation for TarfileUnsafeMembers {
 
 /// S202
 pub(crate) fn tarfile_unsafe_members(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::TARFILE) {
+        return;
+    }
+
     if !call
         .func
         .as_attribute_expr()
@@ -65,10 +70,6 @@ pub(crate) fn tarfile_unsafe_members(checker: &mut Checker, call: &ast::ExprCall
         return;
     }
 
-    if !checker.semantic().seen(&["tarfile"]) {
-        return;
-    }
-
     checker
         .diagnostics
         .push(Diagnostic::new(TarfileUnsafeMembers, call.func.range()));
diff --git a/crates/ruff_linter/src/rules/flake8_bugbear/rules/re_sub_positional_args.rs b/crates/ruff_linter/src/rules/flake8_bugbear/rules/re_sub_positional_args.rs
index 328c9bc711efd..b93aa33a1cd8b 100644
--- a/crates/ruff_linter/src/rules/flake8_bugbear/rules/re_sub_positional_args.rs
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/rules/re_sub_positional_args.rs
@@ -4,6 +4,7 @@ use ruff_python_ast::{self as ast};
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -56,6 +57,10 @@ impl Violation for ReSubPositionalArgs {
 
 /// B034
 pub(crate) fn re_sub_positional_args(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::RE) {
+        return;
+    }
+
     let Some(method) = checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_fromtimestamp.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_fromtimestamp.rs
index ef4e46811a1fe..3c0b56b2f415c 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_fromtimestamp.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_fromtimestamp.rs
@@ -3,6 +3,7 @@ use ruff_text_size::TextRange;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 
@@ -57,6 +58,10 @@ impl Violation for CallDateFromtimestamp {
 }
 
 pub(crate) fn call_date_fromtimestamp(checker: &mut Checker, func: &Expr, location: TextRange) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_today.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_today.rs
index 17b55a14d546f..f2f5c9976bd23 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_today.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_date_today.rs
@@ -3,6 +3,7 @@ use ruff_text_size::TextRange;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 
@@ -56,6 +57,10 @@ impl Violation for CallDateToday {
 }
 
 pub(crate) fn call_date_today(checker: &mut Checker, func: &Expr, location: TextRange) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_fromtimestamp.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_fromtimestamp.rs
index d7942cb6be7e8..f952a791a2bf9 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_fromtimestamp.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_fromtimestamp.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 
 use ruff_python_ast::{self as ast};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -60,6 +61,10 @@ impl Violation for CallDatetimeFromtimestamp {
 }
 
 pub(crate) fn call_datetime_fromtimestamp(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_now_without_tzinfo.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_now_without_tzinfo.rs
index b2db88e8ff009..61b9a16a0efb2 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_now_without_tzinfo.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_now_without_tzinfo.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 
 use ruff_python_ast::{self as ast, Expr};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -56,6 +57,10 @@ impl Violation for CallDatetimeNowWithoutTzinfo {
 }
 
 pub(crate) fn call_datetime_now_without_tzinfo(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_strptime_without_zone.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_strptime_without_zone.rs
index 8390fc9a7c969..90bf275d56f27 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_strptime_without_zone.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_strptime_without_zone.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -64,6 +65,10 @@ impl Violation for CallDatetimeStrptimeWithoutZone {
 
 /// DTZ007
 pub(crate) fn call_datetime_strptime_without_zone(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_today.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_today.rs
index d1b89c794d0de..ef26d93a98e28 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_today.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_today.rs
@@ -3,6 +3,7 @@ use ruff_text_size::TextRange;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 
@@ -55,6 +56,10 @@ impl Violation for CallDatetimeToday {
 }
 
 pub(crate) fn call_datetime_today(checker: &mut Checker, func: &Expr, location: TextRange) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcfromtimestamp.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcfromtimestamp.rs
index 26536d3c5cff7..af335f7a23afc 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcfromtimestamp.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcfromtimestamp.rs
@@ -3,6 +3,7 @@ use ruff_text_size::TextRange;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 
@@ -63,6 +64,10 @@ pub(crate) fn call_datetime_utcfromtimestamp(
     func: &Expr,
     location: TextRange,
 ) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcnow.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcnow.rs
index e9ff0dd363180..b044c24bb54dc 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcnow.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_utcnow.rs
@@ -3,6 +3,7 @@ use ruff_text_size::TextRange;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 
@@ -57,7 +58,12 @@ impl Violation for CallDatetimeUtcnow {
     }
 }
 
+/// DTZ003
 pub(crate) fn call_datetime_utcnow(checker: &mut Checker, func: &Expr, location: TextRange) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(func)
diff --git a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_without_tzinfo.rs b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_without_tzinfo.rs
index 874bfde36b625..ef93dc4f8a562 100644
--- a/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_without_tzinfo.rs
+++ b/crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_without_tzinfo.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 
 use ruff_python_ast::{self as ast, Expr};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -52,6 +53,10 @@ impl Violation for CallDatetimeWithoutTzinfo {
 }
 
 pub(crate) fn call_datetime_without_tzinfo(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::DATETIME) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/all_with_model_form.rs b/crates/ruff_linter/src/rules/flake8_django/rules/all_with_model_form.rs
index 8083575e2a59c..9fd1d11919aa0 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/all_with_model_form.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/all_with_model_form.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, Stmt};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -48,6 +49,10 @@ impl Violation for DjangoAllWithModelForm {
 
 /// DJ007
 pub(crate) fn all_with_model_form(checker: &mut Checker, class_def: &ast::StmtClassDef) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     if !is_model_form(class_def, checker.semantic()) {
         return;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/exclude_with_model_form.rs b/crates/ruff_linter/src/rules/flake8_django/rules/exclude_with_model_form.rs
index d1211c566210a..737a6bf36a4dc 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/exclude_with_model_form.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/exclude_with_model_form.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, Stmt};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -46,6 +47,10 @@ impl Violation for DjangoExcludeWithModelForm {
 
 /// DJ006
 pub(crate) fn exclude_with_model_form(checker: &mut Checker, class_def: &ast::StmtClassDef) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     if !is_model_form(class_def, checker.semantic()) {
         return;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/locals_in_render_function.rs b/crates/ruff_linter/src/rules/flake8_django/rules/locals_in_render_function.rs
index c46657684d236..b4fdb389dc7dd 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/locals_in_render_function.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/locals_in_render_function.rs
@@ -1,7 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
-use ruff_python_semantic::SemanticModel;
+use ruff_python_semantic::{Modules, SemanticModel};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -45,6 +45,10 @@ impl Violation for DjangoLocalsInRenderFunction {
 
 /// DJ003
 pub(crate) fn locals_in_render_function(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     if !checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/model_without_dunder_str.rs b/crates/ruff_linter/src/rules/flake8_django/rules/model_without_dunder_str.rs
index 68e717f3c9901..2dd0889474a00 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/model_without_dunder_str.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/model_without_dunder_str.rs
@@ -3,7 +3,7 @@ use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::is_const_true;
 use ruff_python_ast::identifier::Identifier;
 use ruff_python_ast::{self as ast, Expr, Stmt};
-use ruff_python_semantic::{analyze, SemanticModel};
+use ruff_python_semantic::{analyze, Modules, SemanticModel};
 
 use crate::checkers::ast::Checker;
 
@@ -52,6 +52,10 @@ impl Violation for DjangoModelWithoutDunderStr {
 
 /// DJ008
 pub(crate) fn model_without_dunder_str(checker: &mut Checker, class_def: &ast::StmtClassDef) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     if !is_non_abstract_model(class_def, checker.semantic()) {
         return;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/non_leading_receiver_decorator.rs b/crates/ruff_linter/src/rules/flake8_django/rules/non_leading_receiver_decorator.rs
index 8c7b3ab7a39d0..7a7db458de715 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/non_leading_receiver_decorator.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/non_leading_receiver_decorator.rs
@@ -2,6 +2,7 @@ use ruff_python_ast::Decorator;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -51,6 +52,10 @@ impl Violation for DjangoNonLeadingReceiverDecorator {
 
 /// DJ013
 pub(crate) fn non_leading_receiver_decorator(checker: &mut Checker, decorator_list: &[Decorator]) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     let mut seen_receiver = false;
     for (i, decorator) in decorator_list.iter().enumerate() {
         let is_receiver = decorator.expression.as_call_expr().is_some_and(|call| {
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/nullable_model_string_field.rs b/crates/ruff_linter/src/rules/flake8_django/rules/nullable_model_string_field.rs
index c1fcaac144593..10c0185b3a1bd 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/nullable_model_string_field.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/nullable_model_string_field.rs
@@ -3,7 +3,7 @@ use ruff_python_ast::{self as ast, Expr, Stmt};
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::is_const_true;
-use ruff_python_semantic::SemanticModel;
+use ruff_python_semantic::{Modules, SemanticModel};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -55,6 +55,10 @@ impl Violation for DjangoNullableModelStringField {
 
 /// DJ001
 pub(crate) fn nullable_model_string_field(checker: &mut Checker, body: &[Stmt]) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     for statement in body {
         let Stmt::Assign(ast::StmtAssign { value, .. }) = statement else {
             continue;
diff --git a/crates/ruff_linter/src/rules/flake8_django/rules/unordered_body_content_in_model.rs b/crates/ruff_linter/src/rules/flake8_django/rules/unordered_body_content_in_model.rs
index 635527dcaf014..d03cd2e98f8ae 100644
--- a/crates/ruff_linter/src/rules/flake8_django/rules/unordered_body_content_in_model.rs
+++ b/crates/ruff_linter/src/rules/flake8_django/rules/unordered_body_content_in_model.rs
@@ -3,7 +3,7 @@ use std::fmt;
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, Stmt};
-use ruff_python_semantic::SemanticModel;
+use ruff_python_semantic::{Modules, SemanticModel};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -83,6 +83,10 @@ pub(crate) fn unordered_body_content_in_model(
     checker: &mut Checker,
     class_def: &ast::StmtClassDef,
 ) {
+    if !checker.semantic().seen(Modules::DJANGO) {
+        return;
+    }
+
     if !helpers::is_model(class_def, checker.semantic()) {
         return;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_logging/rules/direct_logger_instantiation.rs b/crates/ruff_linter/src/rules/flake8_logging/rules/direct_logger_instantiation.rs
index 552bee9c4fa5a..a0c35ea42b8d0 100644
--- a/crates/ruff_linter/src/rules/flake8_logging/rules/direct_logger_instantiation.rs
+++ b/crates/ruff_linter/src/rules/flake8_logging/rules/direct_logger_instantiation.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -54,6 +55,10 @@ impl Violation for DirectLoggerInstantiation {
 
 /// LOG001
 pub(crate) fn direct_logger_instantiation(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::LOGGING) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(call.func.as_ref())
diff --git a/crates/ruff_linter/src/rules/flake8_logging/rules/invalid_get_logger_argument.rs b/crates/ruff_linter/src/rules/flake8_logging/rules/invalid_get_logger_argument.rs
index e7d4c8fd2ad5b..ab7c69900e839 100644
--- a/crates/ruff_linter/src/rules/flake8_logging/rules/invalid_get_logger_argument.rs
+++ b/crates/ruff_linter/src/rules/flake8_logging/rules/invalid_get_logger_argument.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -57,6 +58,10 @@ impl Violation for InvalidGetLoggerArgument {
 
 /// LOG002
 pub(crate) fn invalid_get_logger_argument(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::LOGGING) {
+        return;
+    }
+
     let Some(Expr::Name(expr @ ast::ExprName { id, .. })) = call.arguments.find_argument("name", 0)
     else {
         return;
diff --git a/crates/ruff_linter/src/rules/flake8_logging/rules/undocumented_warn.rs b/crates/ruff_linter/src/rules/flake8_logging/rules/undocumented_warn.rs
index 134c4feef7d31..51f1ce691d4fc 100644
--- a/crates/ruff_linter/src/rules/flake8_logging/rules/undocumented_warn.rs
+++ b/crates/ruff_linter/src/rules/flake8_logging/rules/undocumented_warn.rs
@@ -2,6 +2,7 @@ use ruff_python_ast::Expr;
 
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -48,6 +49,10 @@ impl Violation for UndocumentedWarn {
 
 /// LOG009
 pub(crate) fn undocumented_warn(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::LOGGING) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/flake8_pyi/rules/collections_named_tuple.rs b/crates/ruff_linter/src/rules/flake8_pyi/rules/collections_named_tuple.rs
index b045a443746e6..8a666b656f1db 100644
--- a/crates/ruff_linter/src/rules/flake8_pyi/rules/collections_named_tuple.rs
+++ b/crates/ruff_linter/src/rules/flake8_pyi/rules/collections_named_tuple.rs
@@ -2,6 +2,7 @@ use ruff_python_ast::Expr;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -50,6 +51,10 @@ impl Violation for CollectionsNamedTuple {
 
 /// PYI024
 pub(crate) fn collections_named_tuple(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::COLLECTIONS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_expr.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_expr.rs
index 9f45a0adf80d2..97ce8e239f35c 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_expr.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_expr.rs
@@ -5,6 +5,7 @@ use crate::fix::snippet::SourceCodeSnippet;
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_semantic::analyze::typing::is_dict;
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 
@@ -121,6 +122,10 @@ fn is_lowercase_allowed(env_var: &str) -> bool {
 
 /// SIM112
 pub(crate) fn use_capital_environment_variables(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::OS) {
+        return;
+    }
+
     // Ex) `os.environ['foo']`
     if let Expr::Subscript(_) = expr {
         check_os_environ_subscript(checker, expr);
diff --git a/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs b/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs
index fe3bdbada0a91..f1d5395b1ecdb 100644
--- a/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs
+++ b/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs
@@ -58,6 +58,10 @@ pub(crate) fn banned_api<T: Ranged>(checker: &mut Checker, policy: &NameMatchPol
 /// TID251
 pub(crate) fn banned_attribute_access(checker: &mut Checker, expr: &Expr) {
     let banned_api = &checker.settings.flake8_tidy_imports.banned_api;
+    if banned_api.is_empty() {
+        return;
+    }
+
     if let Some((banned_path, ban)) =
         checker
             .semantic()
diff --git a/crates/ruff_linter/src/rules/flake8_trio/rules/async_function_with_timeout.rs b/crates/ruff_linter/src/rules/flake8_trio/rules/async_function_with_timeout.rs
index 048be94b03d5a..5c1b39f076672 100644
--- a/crates/ruff_linter/src/rules/flake8_trio/rules/async_function_with_timeout.rs
+++ b/crates/ruff_linter/src/rules/flake8_trio/rules/async_function_with_timeout.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -48,15 +49,17 @@ pub(crate) fn async_function_with_timeout(
     if !function_def.is_async {
         return;
     }
-    let Some(timeout) = function_def.parameters.find("timeout") else {
-        return;
-    };
 
     // If `trio` isn't in scope, avoid raising the diagnostic.
-    if !checker.semantic().seen(&["trio"]) {
+    if !checker.semantic().seen(Modules::TRIO) {
         return;
     }
 
+    // If the function doesn't have a `timeout` parameter, avoid raising the diagnostic.
+    let Some(timeout) = function_def.parameters.find("timeout") else {
+        return;
+    };
+
     checker.diagnostics.push(Diagnostic::new(
         TrioAsyncFunctionWithTimeout,
         timeout.range(),
diff --git a/crates/ruff_linter/src/rules/flake8_trio/rules/sync_call.rs b/crates/ruff_linter/src/rules/flake8_trio/rules/sync_call.rs
index 5d7dc64bcbc3d..b248b67d49782 100644
--- a/crates/ruff_linter/src/rules/flake8_trio/rules/sync_call.rs
+++ b/crates/ruff_linter/src/rules/flake8_trio/rules/sync_call.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{Expr, ExprCall};
+use ruff_python_semantic::Modules;
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::checkers::ast::Checker;
@@ -51,6 +52,10 @@ impl Violation for TrioSyncCall {
 
 /// TRIO105
 pub(crate) fn sync_call(checker: &mut Checker, call: &ExprCall) {
+    if !checker.semantic().seen(Modules::TRIO) {
+        return;
+    }
+
     let Some(method_name) = ({
         let Some(call_path) = checker.semantic().resolve_call_path(call.func.as_ref()) else {
             return;
diff --git a/crates/ruff_linter/src/rules/flake8_trio/rules/timeout_without_await.rs b/crates/ruff_linter/src/rules/flake8_trio/rules/timeout_without_await.rs
index 6870d99f1abf1..bcad6ffe77a67 100644
--- a/crates/ruff_linter/src/rules/flake8_trio/rules/timeout_without_await.rs
+++ b/crates/ruff_linter/src/rules/flake8_trio/rules/timeout_without_await.rs
@@ -3,6 +3,7 @@ use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::AwaitVisitor;
 use ruff_python_ast::visitor::Visitor;
 use ruff_python_ast::{StmtWith, WithItem};
+use ruff_python_semantic::Modules;
 
 use crate::checkers::ast::Checker;
 use crate::rules::flake8_trio::method_name::MethodName;
@@ -49,6 +50,10 @@ pub(crate) fn timeout_without_await(
     with_stmt: &StmtWith,
     with_items: &[WithItem],
 ) {
+    if !checker.semantic().seen(Modules::TRIO) {
+        return;
+    }
+
     let Some(method_name) = with_items.iter().find_map(|item| {
         let call = item.context_expr.as_call_expr()?;
         let call_path = checker.semantic().resolve_call_path(call.func.as_ref())?;
diff --git a/crates/ruff_linter/src/rules/flake8_trio/rules/unneeded_sleep.rs b/crates/ruff_linter/src/rules/flake8_trio/rules/unneeded_sleep.rs
index d7387f5835d96..fe0845f14df02 100644
--- a/crates/ruff_linter/src/rules/flake8_trio/rules/unneeded_sleep.rs
+++ b/crates/ruff_linter/src/rules/flake8_trio/rules/unneeded_sleep.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, Stmt};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -42,6 +43,10 @@ impl Violation for TrioUnneededSleep {
 
 /// TRIO110
 pub(crate) fn unneeded_sleep(checker: &mut Checker, while_stmt: &ast::StmtWhile) {
+    if !checker.semantic().seen(Modules::TRIO) {
+        return;
+    }
+
     // The body should be a single `await` call.
     let [stmt] = while_stmt.body.as_slice() else {
         return;
diff --git a/crates/ruff_linter/src/rules/flake8_trio/rules/zero_sleep_call.rs b/crates/ruff_linter/src/rules/flake8_trio/rules/zero_sleep_call.rs
index a543ad5a9ae26..ae818b33004e4 100644
--- a/crates/ruff_linter/src/rules/flake8_trio/rules/zero_sleep_call.rs
+++ b/crates/ruff_linter/src/rules/flake8_trio/rules/zero_sleep_call.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, ExprCall, Int, Number};
 use ruff_python_semantic::analyze::typing::find_assigned_value;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -47,6 +48,10 @@ impl AlwaysFixableViolation for TrioZeroSleepCall {
 
 /// TRIO115
 pub(crate) fn zero_sleep_call(checker: &mut Checker, call: &ExprCall) {
+    if !checker.semantic().seen(Modules::TRIO) {
+        return;
+    }
+
     if call.arguments.len() != 1 {
         return;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_sep_split.rs b/crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_sep_split.rs
index 3cba8016e2cd6..8915f9ebdffe0 100644
--- a/crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_sep_split.rs
+++ b/crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_sep_split.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, ExprAttribute};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -53,6 +54,10 @@ impl Violation for OsSepSplit {
 
 /// PTH206
 pub(crate) fn os_sep_split(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::OS) {
+        return;
+    }
+
     let Expr::Attribute(ExprAttribute { attr, .. }) = call.func.as_ref() else {
         return;
     };
diff --git a/crates/ruff_linter/src/rules/numpy/rules/deprecated_function.rs b/crates/ruff_linter/src/rules/numpy/rules/deprecated_function.rs
index 7a106716541f9..ee226b4a438b8 100644
--- a/crates/ruff_linter/src/rules/numpy/rules/deprecated_function.rs
+++ b/crates/ruff_linter/src/rules/numpy/rules/deprecated_function.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -55,6 +56,10 @@ impl Violation for NumpyDeprecatedFunction {
 
 /// NPY003
 pub(crate) fn deprecated_function(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::NUMPY) {
+        return;
+    }
+
     if let Some((existing, replacement)) =
         checker
             .semantic()
diff --git a/crates/ruff_linter/src/rules/numpy/rules/deprecated_type_alias.rs b/crates/ruff_linter/src/rules/numpy/rules/deprecated_type_alias.rs
index 265a04d2ffb2f..cf99b1ec2319e 100644
--- a/crates/ruff_linter/src/rules/numpy/rules/deprecated_type_alias.rs
+++ b/crates/ruff_linter/src/rules/numpy/rules/deprecated_type_alias.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -49,6 +50,10 @@ impl Violation for NumpyDeprecatedTypeAlias {
 
 /// NPY001
 pub(crate) fn deprecated_type_alias(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::NUMPY) {
+        return;
+    }
+
     if let Some(type_name) = checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/numpy/rules/legacy_random.rs b/crates/ruff_linter/src/rules/numpy/rules/legacy_random.rs
index d76507a8c709e..4d40276c6b524 100644
--- a/crates/ruff_linter/src/rules/numpy/rules/legacy_random.rs
+++ b/crates/ruff_linter/src/rules/numpy/rules/legacy_random.rs
@@ -2,6 +2,7 @@ use ruff_python_ast::Expr;
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -59,6 +60,10 @@ impl Violation for NumpyLegacyRandom {
 
 /// NPY002
 pub(crate) fn legacy_random(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::NUMPY) {
+        return;
+    }
+
     if let Some(method_name) = checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/numpy/rules/numpy_2_0_deprecation.rs b/crates/ruff_linter/src/rules/numpy/rules/numpy_2_0_deprecation.rs
index d13773e851607..342957eee6edd 100644
--- a/crates/ruff_linter/src/rules/numpy/rules/numpy_2_0_deprecation.rs
+++ b/crates/ruff_linter/src/rules/numpy/rules/numpy_2_0_deprecation.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -152,6 +153,10 @@ enum Compatibility {
 }
 /// NPY201
 pub(crate) fn numpy_2_0_deprecation(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::NUMPY) {
+        return;
+    }
+
     let maybe_replacement = checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/pandas_vet/rules/attr.rs b/crates/ruff_linter/src/rules/pandas_vet/rules/attr.rs
index e59b8228a5a28..7c0ce38d00dac 100644
--- a/crates/ruff_linter/src/rules/pandas_vet/rules/attr.rs
+++ b/crates/ruff_linter/src/rules/pandas_vet/rules/attr.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::Violation;
 use ruff_diagnostics::{Diagnostic, DiagnosticKind};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Expr, ExprContext};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -45,6 +46,10 @@ impl Violation for PandasUseOfDotValues {
 }
 
 pub(crate) fn attr(checker: &mut Checker, attribute: &ast::ExprAttribute) {
+    if !checker.semantic().seen(Modules::PANDAS) {
+        return;
+    }
+
     // Avoid, e.g., `x.values = y`.
     if matches!(attribute.ctx, ExprContext::Store | ExprContext::Del) {
         return;
diff --git a/crates/ruff_linter/src/rules/pandas_vet/rules/read_table.rs b/crates/ruff_linter/src/rules/pandas_vet/rules/read_table.rs
index f7b5fa9300e6b..b07c7c7c2077d 100644
--- a/crates/ruff_linter/src/rules/pandas_vet/rules/read_table.rs
+++ b/crates/ruff_linter/src/rules/pandas_vet/rules/read_table.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
 use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -46,6 +47,10 @@ impl Violation for PandasUseOfDotReadTable {
 
 /// PD012
 pub(crate) fn use_of_read_table(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::PANDAS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pep8_naming/rules/non_lowercase_variable_in_function.rs b/crates/ruff_linter/src/rules/pep8_naming/rules/non_lowercase_variable_in_function.rs
index b9bf944821b6f..7671b0b3ef59b 100644
--- a/crates/ruff_linter/src/rules/pep8_naming/rules/non_lowercase_variable_in_function.rs
+++ b/crates/ruff_linter/src/rules/pep8_naming/rules/non_lowercase_variable_in_function.rs
@@ -53,6 +53,10 @@ impl Violation for NonLowercaseVariableInFunction {
 
 /// N806
 pub(crate) fn non_lowercase_variable_in_function(checker: &mut Checker, expr: &Expr, name: &str) {
+    if str::is_lowercase(name) {
+        return;
+    }
+
     // Ignore globals.
     if checker
         .semantic()
@@ -62,6 +66,7 @@ pub(crate) fn non_lowercase_variable_in_function(checker: &mut Checker, expr: &E
         return;
     }
 
+    // Ignore explicitly-allowed names.
     if checker
         .settings
         .pep8_naming
@@ -72,10 +77,6 @@ pub(crate) fn non_lowercase_variable_in_function(checker: &mut Checker, expr: &E
         return;
     }
 
-    if str::is_lowercase(name) {
-        return;
-    }
-
     let parent = checker.semantic().current_statement();
     if helpers::is_named_tuple_assignment(parent, checker.semantic())
         || helpers::is_typed_dict_assignment(parent, checker.semantic())
diff --git a/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_default.rs b/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_default.rs
index 82984a8bc3b49..45b68cfa60b06 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_default.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_default.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
 use ruff_python_semantic::analyze::type_inference::{PythonType, ResolvedPythonType};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -43,6 +44,10 @@ impl Violation for InvalidEnvvarDefault {
 
 /// PLW1508
 pub(crate) fn invalid_envvar_default(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::OS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_value.rs b/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_value.rs
index 8a77a6f9d12b0..0706b3ebee299 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_value.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/invalid_envvar_value.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
 use ruff_python_semantic::analyze::type_inference::{PythonType, ResolvedPythonType};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -36,6 +37,10 @@ impl Violation for InvalidEnvvarValue {
 
 /// PLE1507
 pub(crate) fn invalid_envvar_value(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::OS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pylint/rules/subprocess_popen_preexec_fn.rs b/crates/ruff_linter/src/rules/pylint/rules/subprocess_popen_preexec_fn.rs
index bb93faa0bd2ca..04a0ba7a7c783 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/subprocess_popen_preexec_fn.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/subprocess_popen_preexec_fn.rs
@@ -2,6 +2,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 
 use ruff_python_ast::{self as ast};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -50,6 +51,10 @@ impl Violation for SubprocessPopenPreexecFn {
 
 /// PLW1509
 pub(crate) fn subprocess_popen_preexec_fn(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::SUBPROCESS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pylint/rules/subprocess_run_without_check.rs b/crates/ruff_linter/src/rules/pylint/rules/subprocess_run_without_check.rs
index 67b494d6bb700..2aade459df327 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/subprocess_run_without_check.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/subprocess_run_without_check.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Applicability, Diagnostic, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -60,6 +61,10 @@ impl AlwaysFixableViolation for SubprocessRunWithoutCheck {
 
 /// PLW1510
 pub(crate) fn subprocess_run_without_check(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::SUBPROCESS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs
index aed0ff290768a..a7d239b43d74a 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs
@@ -4,19 +4,20 @@ use libcst_native::{
     ImportNames, Name, NameOrAttribute, ParenthesizableWhitespace,
 };
 use log::error;
-use ruff_python_ast::{self as ast, Expr, Stmt};
 
-use crate::fix::codemods::CodegenStylist;
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::call_path::collect_call_path;
 use ruff_python_ast::whitespace::indentation;
+use ruff_python_ast::{self as ast, Stmt};
 use ruff_python_codegen::Stylist;
+use ruff_python_semantic::Modules;
 use ruff_source_file::Locator;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 use crate::cst::matchers::{match_import, match_import_from, match_statement};
+use crate::fix::codemods::CodegenStylist;
 
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 pub(crate) enum MockReference {
@@ -249,23 +250,25 @@ fn format_import_from(
 }
 
 /// UP026
-pub(crate) fn deprecated_mock_attribute(checker: &mut Checker, expr: &Expr) {
-    if let Expr::Attribute(ast::ExprAttribute { value, .. }) = expr {
-        if collect_call_path(value)
-            .is_some_and(|call_path| matches!(call_path.as_slice(), ["mock", "mock"]))
-        {
-            let mut diagnostic = Diagnostic::new(
-                DeprecatedMockImport {
-                    reference_type: MockReference::Attribute,
-                },
-                value.range(),
-            );
-            diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
-                "mock".to_string(),
-                value.range(),
-            )));
-            checker.diagnostics.push(diagnostic);
-        }
+pub(crate) fn deprecated_mock_attribute(checker: &mut Checker, attribute: &ast::ExprAttribute) {
+    if !checker.semantic().seen(Modules::MOCK) {
+        return;
+    }
+
+    if collect_call_path(&attribute.value)
+        .is_some_and(|call_path| matches!(call_path.as_slice(), ["mock", "mock"]))
+    {
+        let mut diagnostic = Diagnostic::new(
+            DeprecatedMockImport {
+                reference_type: MockReference::Attribute,
+            },
+            attribute.value.range(),
+        );
+        diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+            "mock".to_string(),
+            attribute.value.range(),
+        )));
+        checker.diagnostics.push(diagnostic);
     }
 }
 
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/replace_stdout_stderr.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/replace_stdout_stderr.rs
index fa1f2c742786c..3290e8f900c3f 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/replace_stdout_stderr.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/replace_stdout_stderr.rs
@@ -3,6 +3,7 @@ use anyhow::Result;
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::{self as ast, Keyword};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -53,6 +54,10 @@ impl Violation for ReplaceStdoutStderr {
 
 /// UP022
 pub(crate) fn replace_stdout_stderr(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::SUBPROCESS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/replace_universal_newlines.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/replace_universal_newlines.rs
index 9e97481dba1f6..41c40b8034ce7 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/replace_universal_newlines.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/replace_universal_newlines.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -49,6 +50,10 @@ impl AlwaysFixableViolation for ReplaceUniversalNewlines {
 
 /// UP021
 pub(crate) fn replace_universal_newlines(checker: &mut Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen(Modules::SUBPROCESS) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(&call.func)
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/typing_text_str_alias.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/typing_text_str_alias.rs
index 86d9e6b28bf99..912907d96604e 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/typing_text_str_alias.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/typing_text_str_alias.rs
@@ -2,6 +2,7 @@ use ruff_python_ast::Expr;
 
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -46,6 +47,10 @@ impl Violation for TypingTextStrAlias {
 
 /// UP019
 pub(crate) fn typing_text_str_alias(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::TYPING) {
+        return;
+    }
+
     if checker
         .semantic()
         .resolve_call_path(expr)
diff --git a/crates/ruff_linter/src/rules/refurb/rules/regex_flag_alias.rs b/crates/ruff_linter/src/rules/refurb/rules/regex_flag_alias.rs
index bd3fcdd56c64a..5bcc338f8c01b 100644
--- a/crates/ruff_linter/src/rules/refurb/rules/regex_flag_alias.rs
+++ b/crates/ruff_linter/src/rules/refurb/rules/regex_flag_alias.rs
@@ -1,6 +1,7 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::Expr;
+use ruff_python_semantic::Modules;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -52,6 +53,10 @@ impl AlwaysFixableViolation for RegexFlagAlias {
 
 /// FURB167
 pub(crate) fn regex_flag_alias(checker: &mut Checker, expr: &Expr) {
+    if !checker.semantic().seen(Modules::RE) {
+        return;
+    }
+
     let Some(flag) =
         checker
             .semantic()
diff --git a/crates/ruff_python_semantic/src/analyze/typing.rs b/crates/ruff_python_semantic/src/analyze/typing.rs
index 39eec17a53f88..ea2bb33a36f27 100644
--- a/crates/ruff_python_semantic/src/analyze/typing.rs
+++ b/crates/ruff_python_semantic/src/analyze/typing.rs
@@ -13,7 +13,7 @@ use ruff_text_size::Ranged;
 
 use crate::analyze::type_inference::{PythonType, ResolvedPythonType};
 use crate::model::SemanticModel;
-use crate::{Binding, BindingKind};
+use crate::{Binding, BindingKind, Modules};
 
 #[derive(Debug, Copy, Clone)]
 pub enum Callable {
@@ -101,18 +101,21 @@ impl std::fmt::Display for ModuleMember {
 /// Returns the PEP 585 standard library generic variant for a `typing` module reference, if such
 /// a variant exists.
 pub fn to_pep585_generic(expr: &Expr, semantic: &SemanticModel) -> Option<ModuleMember> {
-    semantic.resolve_call_path(expr).and_then(|call_path| {
-        let [module, member] = call_path.as_slice() else {
-            return None;
-        };
-        as_pep_585_generic(module, member).map(|(module, member)| {
-            if module.is_empty() {
-                ModuleMember::BuiltIn(member)
-            } else {
-                ModuleMember::Member(module, member)
-            }
+    Some(expr)
+        .filter(|_| semantic.seen(Modules::TYPING | Modules::TYPING_EXTENSIONS))
+        .and_then(|expr| semantic.resolve_call_path(expr))
+        .and_then(|call_path| {
+            let [module, member] = call_path.as_slice() else {
+                return None;
+            };
+            as_pep_585_generic(module, member).map(|(module, member)| {
+                if module.is_empty() {
+                    ModuleMember::BuiltIn(member)
+                } else {
+                    ModuleMember::Member(module, member)
+                }
+            })
         })
-    })
 }
 
 /// Return whether a given expression uses a PEP 585 standard library generic.
diff --git a/crates/ruff_python_semantic/src/model.rs b/crates/ruff_python_semantic/src/model.rs
index 3e15e62aff7d2..963a1d5aa2ee5 100644
--- a/crates/ruff_python_semantic/src/model.rs
+++ b/crates/ruff_python_semantic/src/model.rs
@@ -120,6 +120,9 @@ pub struct SemanticModel<'a> {
     /// Flags for the semantic model.
     pub flags: SemanticModelFlags,
 
+    /// Modules that have been seen by the semantic model.
+    pub seen: Modules,
+
     /// Exceptions that have been handled by the current scope.
     pub handled_exceptions: Vec<Exceptions>,
 
@@ -149,11 +152,41 @@ impl<'a> SemanticModel<'a> {
             delayed_annotations: FxHashMap::default(),
             rebinding_scopes: FxHashMap::default(),
             flags: SemanticModelFlags::new(path),
+            seen: Modules::empty(),
             handled_exceptions: Vec::default(),
             resolved_names: FxHashMap::default(),
         }
     }
 
+    pub fn see(&mut self, module: &str) {
+        match module {
+            "trio" => self.seen.insert(Modules::TRIO),
+            "numpy" => self.seen.insert(Modules::NUMPY),
+            "pandas" => self.seen.insert(Modules::PANDAS),
+            "pytest" => self.seen.insert(Modules::PYTEST),
+            "django" => self.seen.insert(Modules::DJANGO),
+            "six" => self.seen.insert(Modules::SIX),
+            "logging" => self.seen.insert(Modules::LOGGING),
+            "typing" => self.seen.insert(Modules::TYPING),
+            "typing_extensions" => self.seen.insert(Modules::TYPING_EXTENSIONS),
+            "tarfile" => self.seen.insert(Modules::TARFILE),
+            "re" => self.seen.insert(Modules::RE),
+            "collections" => self.seen.insert(Modules::COLLECTIONS),
+            "mock" => self.seen.insert(Modules::MOCK),
+            "os" => self.seen.insert(Modules::OS),
+            "datetime" => self.seen.insert(Modules::DATETIME),
+            "subprocess" => self.seen.insert(Modules::SUBPROCESS),
+            _ => {}
+        }
+    }
+
+    /// Return `true` if the module at the given path was seen anywhere in the semantic model.
+    /// This includes both direct imports (`import trio`) and member imports (`from trio import
+    /// TrioTask`).
+    pub fn seen(&self, module: Modules) -> bool {
+        self.seen.intersects(module)
+    }
+
     /// Return the [`Binding`] for the given [`BindingId`].
     #[inline]
     pub fn binding(&self, id: BindingId) -> &Binding {
@@ -1297,16 +1330,6 @@ impl<'a> SemanticModel<'a> {
         exceptions
     }
 
-    /// Return `true` if the module at the given path was seen anywhere in the semantic model.
-    /// This includes both direct imports (`import trio`) and member imports (`from trio import
-    /// TrioTask`).
-    pub fn seen(&self, module: &[&str]) -> bool {
-        self.bindings
-            .iter()
-            .filter_map(Binding::as_any_import)
-            .any(|import| import.call_path().starts_with(module))
-    }
-
     /// Generate a [`Snapshot`] of the current semantic model.
     pub fn snapshot(&self) -> Snapshot {
         Snapshot {
@@ -1532,6 +1555,27 @@ impl ShadowedBinding {
     }
 }
 
+bitflags! {
+    pub struct Modules: u16 {
+        const TRIO = 1 << 0;
+        const DJANGO = 1 << 1;
+        const NUMPY = 1 << 2;
+        const SIX = 1 << 3;
+        const PANDAS = 1 << 4;
+        const LOGGING = 1 << 5;
+        const TYPING = 1 << 6;
+        const TYPING_EXTENSIONS = 1 << 7;
+        const PYTEST = 1 << 8;
+        const TARFILE = 1 << 9;
+        const RE = 1 << 10;
+        const COLLECTIONS = 1 << 11;
+        const MOCK = 1 << 12;
+        const OS = 1 << 13;
+        const DATETIME = 1 << 14;
+        const SUBPROCESS = 1 << 15;
+    }
+}
+
 bitflags! {
     /// Flags indicating the current model state.
     #[derive(Debug, Default, Copy, Clone, Eq, PartialEq)]