[flake8-errmsg] Exclude typing.cast from EM101 (#19656)

## Summary

Fixes #19596

crates/ruff_linter/resources/test/fixtures/flake8_errmsg/EM.py

@@ -88,3 +88,25 @@ def f_multi_line_string2():
             example="example"
         )
     )
+
+
+def raise_typing_cast_exception():
+    import typing
+    raise typing.cast("Exception", None)
+
+
+def f_typing_cast_excluded():
+    from typing import cast
+    raise cast(RuntimeError, "This should not trigger EM101")
+
+
+def f_typing_cast_excluded_import():
+    import typing
+    raise typing.cast(RuntimeError, "This should not trigger EM101")
+
+
+def f_typing_cast_excluded_aliased():
+    from typing import cast as my_cast
+    raise my_cast(RuntimeError, "This should not trigger EM101")
+
+

crates/ruff_linter/src/rules/flake8_errmsg/rules/string_in_exception.rs

@@ -182,11 +182,19 @@ impl Violation for DotFormatInException {
 
 /// EM101, EM102, EM103
 pub(crate) fn string_in_exception(checker: &Checker, stmt: &Stmt, exc: &Expr) {
-    if let Expr::Call(ast::ExprCall {
+    let Expr::Call(ast::ExprCall {
+        func,
         arguments: Arguments { args, .. },
         ..
     }) = exc
-    {
+    else {
+        return;
+    };
+
+    if checker.semantic().match_typing_expr(func, "cast") {
+        return;
+    }
+
     if let Some(first) = args.first() {
         match first {
             // Check for string literals.
@@ -195,9 +203,7 @@ pub(crate) fn string_in_exception(checker: &Checker, stmt: &Stmt, exc: &Expr) {
                     if string.len() >= checker.settings().flake8_errmsg.max_string_length {
                         let mut diagnostic =
                             checker.report_diagnostic(RawStringInException, first.range());
-                            if let Some(indentation) =
+                        if let Some(indentation) = whitespace::indentation(checker.source(), stmt) {
-                                whitespace::indentation(checker.source(), stmt)
-                            {
                             diagnostic.set_fix(generate_fix(
                                 stmt,
                                 first,
@@ -217,9 +223,7 @@ pub(crate) fn string_in_exception(checker: &Checker, stmt: &Stmt, exc: &Expr) {
                     {
                         let mut diagnostic =
                             checker.report_diagnostic(RawStringInException, first.range());
-                            if let Some(indentation) =
+                        if let Some(indentation) = whitespace::indentation(checker.source(), stmt) {
-                                whitespace::indentation(checker.source(), stmt)
-                            {
                             diagnostic.set_fix(generate_fix(
                                 stmt,
                                 first,
@@ -250,9 +254,7 @@ pub(crate) fn string_in_exception(checker: &Checker, stmt: &Stmt, exc: &Expr) {
             // Check for .format() calls.
             Expr::Call(ast::ExprCall { func, .. }) => {
                 if checker.is_rule_enabled(Rule::DotFormatInException) {
-                        if let Expr::Attribute(ast::ExprAttribute { value, attr, .. }) =
+                    if let Expr::Attribute(ast::ExprAttribute { value, attr, .. }) = func.as_ref() {
-                            func.as_ref()
-                        {
                         if attr == "format" && value.is_literal_expr() {
                             let mut diagnostic =
                                 checker.report_diagnostic(DotFormatInException, first.range());
@@ -274,7 +276,6 @@ pub(crate) fn string_in_exception(checker: &Checker, stmt: &Stmt, exc: &Expr) {
             _ => {}
         }
     }
-    }
 }
 
 /// Generate the [`Fix`] for EM001, EM002, and EM003 violations.

crates/ruff_linter/src/rules/flake8_errmsg/snapshots/ruff_linter__rules__flake8_errmsg__tests__custom.snap

@@ -278,3 +278,6 @@ EM.py:84:9: EM103 [*] Exception must not use a `.format()` string directly, assi
    91 |+    raise RuntimeError(
    92 |+        msg
    93 |+    )
+91 94 | 
+92 95 | 
+93 96 | def raise_typing_cast_exception():

crates/ruff_linter/src/rules/flake8_errmsg/snapshots/ruff_linter__rules__flake8_errmsg__tests__defaults.snap

@@ -343,3 +343,6 @@ EM.py:84:9: EM103 [*] Exception must not use a `.format()` string directly, assi
    91 |+    raise RuntimeError(
    92 |+        msg
    93 |+    )
+91 94 | 
+92 95 | 
+93 96 | def raise_typing_cast_exception():