feat(semantic): check optional parameters (#2263)

crates/oxc_ast/src/ast/js.rs

@@ -1602,6 +1602,10 @@ impl<'a> BindingPatternKind<'a> {
     pub fn is_binding_identifier(&self) -> bool {
         matches!(self, Self::BindingIdentifier(_))
     }
+
+    pub fn is_assignment_pattern(&self) -> bool {
+        matches!(self, Self::AssignmentPattern(_))
+    }
 }
 
 #[derive(Debug, Hash)]

crates/oxc_semantic/src/checker/typescript.rs

@@ -40,9 +40,25 @@ fn check_variable_declarator(decl: &VariableDeclarator, ctx: &SemanticBuilder<'_
 }
 
 fn check_formal_parameters(params: &FormalParameters, ctx: &SemanticBuilder<'_>) {
+    #[derive(Debug, Error, Diagnostic)]
+    #[error("A required parameter cannot follow an optional parameter.")]
+    #[diagnostic()]
+    struct RequiredParameterAfterOptionalParameter(#[label] Span);
+
     if !params.is_empty() && params.kind == FormalParameterKind::Signature {
         check_duplicate_bound_names(params, ctx);
     }
+
+    let mut has_optional = false;
+    for item in &params.items {
+        // function a(optional?: number, required: number) { }
+        if has_optional && !item.pattern.optional && !item.pattern.kind.is_assignment_pattern() {
+            ctx.error(RequiredParameterAfterOptionalParameter(item.span));
+        }
+        if item.pattern.optional {
+            has_optional = true;
+        }
+    }
 }
 
 fn check_duplicate_bound_names<T: BoundNames>(bound_names: &T, ctx: &SemanticBuilder<'_>) {

tasks/coverage/parser_babel.snap

@@ -1,7 +1,7 @@
 parser_babel Summary:
 AST Parsed     : 2090/2096 (99.71%)
-Positive Passed: 2088/2096 (99.62%)
+Positive Passed: 2086/2096 (99.52%)
-Negative Passed: 1351/1500 (90.07%)
+Negative Passed: 1355/1500 (90.33%)
 Expect Syntax Error: "annex-b/disabled/1.1-html-comments-close/input.js"
 Expect Syntax Error: "annex-b/disabled/3.1-sloppy-labeled-functions/input.js"
 Expect Syntax Error: "annex-b/disabled/3.1-sloppy-labeled-functions-if-body/input.js"
@@ -71,7 +71,6 @@ Expect Syntax Error: "typescript/class/modifiers-index-signatures/input.ts"
 Expect Syntax Error: "typescript/class/modifiers-invalid-order/input.ts"
 Expect Syntax Error: "typescript/class/modifiers-override-errors/input.ts"
 Expect Syntax Error: "typescript/class/parameter-properties-binding-patterns/input.ts"
-Expect Syntax Error: "typescript/class/parameter-properties-not-constructor/input.ts"
 Expect Syntax Error: "typescript/class/private-fields-modifier-abstract/input.ts"
 Expect Syntax Error: "typescript/class/private-fields-modifier-private/input.ts"
 Expect Syntax Error: "typescript/class/private-fields-modifier-protected/input.ts"
@@ -94,9 +93,6 @@ Expect Syntax Error: "typescript/expect-plugin/export-type-named/input.js"
 Expect Syntax Error: "typescript/export/double-declare/input.ts"
 Expect Syntax Error: "typescript/export/equals-in-script/input.ts"
 Expect Syntax Error: "typescript/function/empty-type-parameters/input.ts"
-Expect Syntax Error: "typescript/function/parameter-properties/input.ts"
-Expect Syntax Error: "typescript/function/pattern-optional-parameters/input.ts"
-Expect Syntax Error: "typescript/function/pattern-optional-parameters-arrow/input.ts"
 Expect Syntax Error: "typescript/import/equals-in-script/input.ts"
 Expect Syntax Error: "typescript/import/equals-require-in-script/input.ts"
 Expect Syntax Error: "typescript/import/export-import-type/input.ts"
@@ -187,6 +183,22 @@ Expect to Parse: "typescript/class/constructor-with-modifier-names/input.ts"
  4 │ }
    ╰────
 
+Expect to Parse: "typescript/class/parameter-properties/input.ts"
+  × A required parameter cannot follow an optional parameter.
+   ╭─[typescript/class/parameter-properties/input.ts:6:1]
+ 6 │         private pi?: number,
+ 7 │         public readonly pur,
+   ·         ───────────────────
+ 8 │         // Also works on AssignmentPattern
+   ╰────
+
+Expect to Parse: "typescript/function/declare-pattern-parameters/input.ts"
+  × A required parameter cannot follow an optional parameter.
+   ╭─[typescript/function/declare-pattern-parameters/input.ts:1:1]
+ 1 │ declare function f([]?, {})
+   ·                         ──
+   ╰────
+
 Expect to Parse: "typescript/interface/get-set-properties/input.ts"
   × Expected `(` but found `:`
    ╭─[typescript/interface/get-set-properties/input.ts:1:1]
@@ -9775,6 +9787,14 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    ╰────
   help: Try insert a semicolon here
 
+  × A required parameter cannot follow an optional parameter.
+   ╭─[typescript/class/parameter-properties-not-constructor/input.ts:6:1]
+ 6 │         private pi?: number,
+ 7 │         public readonly pur,
+   ·         ───────────────────
+ 8 │         // Also works on AssignmentPattern
+   ╰────
+
   × Unexpected token
    ╭─[typescript/const/invalid-initializer-ambient-context/input.ts:1:1]
  1 │ declare module N {
@@ -9822,6 +9842,26 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    ·                ───
    ╰────
 
+  × A required parameter cannot follow an optional parameter.
+   ╭─[typescript/function/parameter-properties/input.ts:5:1]
+ 5 │   private pi?: number,
+ 6 │   public readonly pur,
+   ·   ───────────────────
+ 7 │   readonly x = 0,
+   ╰────
+
+  × A required parameter cannot follow an optional parameter.
+   ╭─[typescript/function/pattern-optional-parameters/input.ts:1:1]
+ 1 │ function f([]?, {}) {}
+   ·                 ──
+   ╰────
+
+  × A required parameter cannot follow an optional parameter.
+   ╭─[typescript/function/pattern-optional-parameters-arrow/input.ts:1:1]
+ 1 │ ([]?, {}) => {}
+   ·       ──
+   ╰────
+
   × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[typescript/interface/declare-new-line/input.ts:1:1]
  1 │ declare interface

tasks/coverage/parser_typescript.snap

@@ -1,7 +1,7 @@
 parser_typescript Summary:
 AST Parsed     : 5239/5243 (99.92%)
 Positive Passed: 5232/5243 (99.79%)
-Negative Passed: 1024/4879 (20.99%)
+Negative Passed: 1025/4879 (21.01%)
 Expect Syntax Error: "compiler/ClassDeclaration10.ts"
 Expect Syntax Error: "compiler/ClassDeclaration11.ts"
 Expect Syntax Error: "compiler/ClassDeclaration13.ts"
@@ -3210,7 +3210,6 @@ Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParame
 Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList16.ts"
 Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList17.ts"
 Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList2.ts"
-Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList3.ts"
 Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList4.ts"
 Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList7.ts"
 Expect Syntax Error: "conformance/parser/ecmascript5/ParameterLists/parserParameterList8.ts"
@@ -6370,6 +6369,13 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
     ╰────
   help: Try insert a semicolon here
 
+  × A required parameter cannot follow an optional parameter.
+   ╭─[compiler/fatarrowfunctionsOptionalArgsErrors1.ts:1:1]
+ 1 │ (arg1?, arg2) => 101;
+   ·         ────
+ 2 │ (...arg?) => 102;
+   ╰────
+
   × A rest parameter cannot have an initializer
    ╭─[compiler/fatarrowfunctionsOptionalArgsErrors1.ts:3:1]
  3 │ (...arg) => 103;
@@ -15798,6 +15804,22 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
  10 │ function fn5() { }
     ╰────
 
+  × A required parameter cannot follow an optional parameter.
+   ╭─[conformance/functions/functionOverloadErrorsSyntax.ts:1:1]
+ 1 │ //Function overload signature with optional parameter followed by non-optional parameter
+ 2 │ function fn4a(x?: number, y: string);
+   ·                           ─────────
+ 3 │ function fn4a() { }
+   ╰────
+
+  × A required parameter cannot follow an optional parameter.
+   ╭─[conformance/functions/functionOverloadErrorsSyntax.ts:4:1]
+ 4 │ 
+ 5 │ function fn4b(n: string, x?: number, y: string);
+   ·                                      ─────────
+ 6 │ function fn4b() { }
+   ╰────
+
   × Illegal 'use strict' directive in function with non-simple parameter list
    ╭─[conformance/functions/functionWithUseStrictAndSimpleParameterList_es2016.ts:3:1]
  3 │ function a(a = 10) {
@@ -17062,6 +17084,14 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
  3 │ }
    ╰────
 
+  × A required parameter cannot follow an optional parameter.
+   ╭─[conformance/parser/ecmascript5/ParameterLists/parserParameterList3.ts:1:1]
+ 1 │ class C {
+ 2 │   F(A?, B) { }
+   ·         ─
+ 3 │ }
+   ╰────
+
   × Expected `)` but found `Identifier`
    ╭─[conformance/parser/ecmascript5/ParameterLists/parserParameterList5.ts:1:1]
  1 │ function A(): (public B) => C {