fix(linter): enhance help diagnostic messages for more eslint rules

apps/oxlint/src/snapshots/fixtures__eslint_and_typescript_alias_rules_-c oxlint-eslint.json test.js -c oxlint-typescript.json test.js@oxlint.snap

@@ -13,6 +13,7 @@ working directory: fixtures/eslint_and_typescript_alias_rules
    :                                ^^^^
  5 | 
    `----
+  help: Use a named constant instead of a magic number to make the code more readable and maintainable.
 
 Found 0 warnings and 1 error.
 Finished in <variable>ms on 1 file with 1 rules using 1 threads.
@@ -32,6 +33,7 @@ working directory: fixtures/eslint_and_typescript_alias_rules
    :                                ^^^^
  5 | 
    `----
+  help: Use a named constant instead of a magic number to make the code more readable and maintainable.
 
 Found 0 warnings and 1 error.
 Finished in <variable>ms on 1 file with 1 rules using 1 threads.

crates/oxc_linter/src/rules/eslint/no_magic_numbers.rs

@@ -18,11 +18,15 @@ enum NoMagicNumberReportReason {
 }
 
 fn must_use_const_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Number constants declarations must use 'const'.").with_label(span)
+    OxcDiagnostic::warn("Number constants declarations must use 'const'.")
+        .with_help("Use 'const' instead of 'let' or 'var' to declare number constants to make their immutability explicit.")
+        .with_label(span)
 }
 
 fn no_magic_number_diagnostic(span: Span, raw: &str) -> OxcDiagnostic {
-    OxcDiagnostic::warn(format!("No magic number: {raw}")).with_label(span)
+    OxcDiagnostic::warn(format!("No magic number: {raw}"))
+        .with_help("Use a named constant instead of a magic number to make the code more readable and maintainable.")
+        .with_label(span)
 }
 
 #[derive(Debug, Default, Clone)]

crates/oxc_linter/src/rules/eslint/no_misleading_character_class.rs

@@ -17,23 +17,33 @@ use crate::{
 };
 
 fn surrogate_pair_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Unexpected surrogate pair in character class.").with_label(span)
+    OxcDiagnostic::warn("Unexpected surrogate pair in character class.")
+        .with_help("Add the Unicode flag 'u' to the regular expression or use Unicode code point escapes (e.g., \\u{1F44D}) instead of surrogate pairs.")
+        .with_label(span)
 }
 
 fn combining_class_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Unexpected combining class in character class.").with_label(span)
+    OxcDiagnostic::warn("Unexpected combining class in character class.")
+        .with_help("Replace the character with its normalized form (NFC) or use Unicode code point escapes instead of combining sequences.")
+        .with_label(span)
 }
 
 fn emoji_modifiers_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Unexpected emoji modifier in character class.").with_label(span)
+    OxcDiagnostic::warn("Unexpected emoji modifier in character class.")
+        .with_help("Use Unicode code point escapes (e.g., \\u{1F3FB} for the light skin tone modifier) instead of emoji modifier sequences in character classes.")
+        .with_label(span)
 }
 
 fn regional_indicator_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Unexpected regional indicator in character class.").with_label(span)
+    OxcDiagnostic::warn("Unexpected regional indicator in character class.")
+        .with_help("Use Unicode code point escapes (e.g., \\u{1F1EF} for the regional indicator symbol for 'J') instead of regional indicator symbol pairs in character classes.")
+        .with_label(span)
 }
 
 fn zwj_diagnostic(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Unexpected joined character sequence in character class.").with_label(span)
+    OxcDiagnostic::warn("Unexpected joined character sequence in character class.")
+        .with_help("Use Unicode code point escapes (e.g., \\u{1F468}\\u200D\\u{1F469} for '👨‍👩') instead of zero-width joiner sequences in character classes.")
+        .with_label(span)
 }
 
 #[derive(Debug, Default, Clone, JsonSchema, Deserialize)]

crates/oxc_linter/src/rules/eslint/no_redeclare.rs

@@ -12,14 +12,17 @@ use crate::{
 };
 
 fn no_redeclare_diagnostic(name: &str, decl_span: Span, re_decl_span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn(format!("'{name}' is already defined.")).with_labels([
-        decl_span.label(format!("'{name}' is already defined.")),
-        re_decl_span.label("It can not be redeclared here."),
-    ])
+    OxcDiagnostic::warn(format!("'{name}' is already defined."))
+        .with_help("Use a different variable name or remove the duplicate declaration.")
+        .with_labels([
+            decl_span.label(format!("'{name}' is already defined.")),
+            re_decl_span.label("It can not be redeclared here."),
+        ])
 }
 
 fn no_redeclare_as_builtin_in_diagnostic(name: &str, span: Span) -> OxcDiagnostic {
     OxcDiagnostic::warn(format!("'{name}' is already defined as a built-in global variable."))
+        .with_help("Use a different variable name to avoid shadowing the built-in global.")
         .with_label(span)
 }
 

crates/oxc_linter/src/rules/eslint/radix.rs

@@ -11,7 +11,9 @@ use serde::{Deserialize, Serialize};
 use crate::{AstNode, context::LintContext, rule::Rule};
 
 fn missing_parameters(span: Span) -> OxcDiagnostic {
-    OxcDiagnostic::warn("Missing parameters.").with_label(span)
+    OxcDiagnostic::warn("Missing parameters.")
+        .with_help("Add parameters for parsing numbers, e.g., `parseInt('10', 10)`.")
+        .with_label(span)
 }
 
 fn missing_radix(span: Span) -> OxcDiagnostic {
@@ -22,6 +24,7 @@ fn missing_radix(span: Span) -> OxcDiagnostic {
 
 fn invalid_radix(span: Span) -> OxcDiagnostic {
     OxcDiagnostic::warn("Invalid radix parameter, must be an integer between 2 and 36.")
+        .with_help("The radix parameter should be an integer between 2 and 36, or a variable that is not `undefined`.")
         .with_label(span)
 }