fix(parser): forbid type parameters on quoted constructors (#25696)

Quoted constructor methods bypassed the AST-based constructor validation. Validate type parameters after resolving the method key, preserving the AST shape.

Validation: `just ready`, parser conformance, and allocation checks.

Closes #25692.

AI-assisted with Codex.

crates/oxc_parser/src/js/class.rs

@@ -829,7 +829,9 @@ impl<'a, C: Config> ParserImpl<'a, C> {
                     self.error(diagnostics::static_prototype(span));
                 }
             } else if name == "constructor" {
-                if matches!(method.kind, MethodDefinitionKind::Get | MethodDefinitionKind::Set) {
+                let is_accessor =
+                    matches!(method.kind, MethodDefinitionKind::Get | MethodDefinitionKind::Set);
+                if is_accessor {
                     self.error(diagnostics::constructor_getter_setter(span));
                 }
                 if method.value.r#async {
@@ -841,6 +843,9 @@ impl<'a, C: Config> ParserImpl<'a, C> {
                 if method.r#type.is_abstract() {
                     self.error(diagnostics::illegal_abstract_modifier(span));
                 }
+                if !is_accessor && let Some(type_parameters) = &method.value.type_parameters {
+                    self.error(diagnostics::ts_constructor_type_parameter(type_parameters.span));
+                }
             }
         }
 
@@ -881,10 +886,6 @@ impl<'a, C: Config> ParserImpl<'a, C> {
             // class Foo { constructor(this: number) {} }
             self.error(diagnostics::ts_constructor_this_parameter(this_param.span));
         }
-        if let Some(type_sig) = &method.value.type_parameters {
-            // class Foo { constructor<T>(param: T ) {} }
-            self.error(diagnostics::ts_constructor_type_parameter(type_sig.span));
-        }
         if method.value.body.is_some()
             && let Some(return_type) = &method.value.return_type
         {

tasks/coverage/misc/fail/oxc-25692.ts

@@ -0,0 +1,7 @@
+class A {
+  'constructor'<T>() {}
+}
+
+class B {
+  get 'constructor'<T>() {}
+}

tasks/coverage/snapshots/parser_misc.snap

@@ -1,7 +1,7 @@
 parser_misc Summary:
 AST Parsed     : 78/78 (100.00%)
 Positive Passed: 78/78 (100.00%)
-Negative Passed: 161/161 (100.00%)
+Negative Passed: 162/162 (100.00%)
 
   × Cannot assign to 'arguments' in strict mode
    ╭─[misc/fail/arguments-eval-ambient.ts:2:13]
@@ -3941,6 +3941,31 @@ Negative Passed: 161/161 (100.00%)
     ╰────
   help: Allowed modifiers are: private, protected, public, static, abstract, override
 
+  × TS(1092): Type parameters cannot appear on a constructor declaration
+   ╭─[misc/fail/oxc-25692.ts:2:16]
+ 1 │ class A {
+ 2 │   'constructor'<T>() {}
+   ·                ───
+ 3 │ }
+   ╰────
+  help: Instead, add type parameters to the class itself
+
+  × Constructor can't have get/set modifier
+   ╭─[misc/fail/oxc-25692.ts:6:7]
+ 5 │ class B {
+ 6 │   get 'constructor'<T>() {}
+   ·       ─────────────
+ 7 │ }
+   ╰────
+
+  × TS(1094): An accessor cannot have type parameters.
+   ╭─[misc/fail/oxc-25692.ts:6:20]
+ 5 │ class B {
+ 6 │   get 'constructor'<T>() {}
+   ·                    ───
+ 7 │ }
+   ╰────
+
   × Expected `:` but found `[`
    ╭─[misc/fail/oxc-3320.tsx:1:8]
  1 │ m< $<{3[   $<{3[  $<{3[ m< m$<{3[ m< mm< $<{3[   $<{3[  $<{3[ m< m$<{3[ m< m$<{3[  $<{3[ m< m$<{3[