fix(semantic): ? on variable declaration type annotations is a syntax error (#5956)

Closes #5955

crates/oxc_semantic/src/checker/typescript.rs

@@ -52,7 +52,7 @@ fn unexpected_optional(span: Span) -> OxcDiagnostic {
 #[allow(clippy::cast_possible_truncation)]
 pub fn check_variable_declarator(decl: &VariableDeclarator, ctx: &SemanticBuilder<'_>) {
     if decl.id.optional {
-        let start = decl.id.span().end;
+        let start = decl.id.span().start;
         let Some(offset) = ctx.source_text[start as usize..].find('?') else { return };
         let offset = start + offset as u32;
         ctx.error(unexpected_optional(Span::new(offset, offset)));

tasks/coverage/misc/fail/oxc-5955-1.ts

@@ -0,0 +1,2 @@
+const x?: number = 1;
+

tasks/coverage/misc/fail/oxc-5955-2.ts

@@ -0,0 +1,4 @@
+
+interface B {
+    e()?: number;
+}

tasks/coverage/misc/fail/oxc-5955-3.ts

@@ -0,0 +1,3 @@
+class A {
+    [key: string]?: number;
+}

tasks/coverage/misc/pass/oxc-5955.ts

@@ -0,0 +1,7 @@
+const a = (b?: number) => b;
+class B {
+    c?: number = 1;
+}
+interface C {
+    d?: number;
+}

tasks/coverage/snapshots/codegen_misc.snap

@@ -1,3 +1,3 @@
 codegen_misc Summary:
-AST Parsed     : 29/29 (100.00%)
-Positive Passed: 29/29 (100.00%)
+AST Parsed     : 30/30 (100.00%)
+Positive Passed: 30/30 (100.00%)

tasks/coverage/snapshots/parser_misc.snap

@@ -1,7 +1,7 @@
 parser_misc Summary:
-AST Parsed     : 29/29 (100.00%)
-Positive Passed: 29/29 (100.00%)
-Negative Passed: 17/17 (100.00%)
+AST Parsed     : 30/30 (100.00%)
+Positive Passed: 30/30 (100.00%)
+Negative Passed: 20/20 (100.00%)
 
   × Unexpected token
    ╭─[misc/fail/oxc-169.js:2:1]
@@ -244,6 +244,29 @@ Negative Passed: 17/17 (100.00%)
    ·      ───────
    ╰────
 
+  × Unexpected `?` operator
+   ╭─[misc/fail/oxc-5955-1.ts:1:8]
+ 1 │ const x?: number = 1;
+   ·        ▲
+ 2 │ 
+   ╰────
+
+  × Unexpected token
+   ╭─[misc/fail/oxc-5955-2.ts:3:8]
+ 2 │ interface B {
+ 3 │     e()?: number;
+   ·        ─
+ 4 │ }
+   ╰────
+
+  × Unexpected token
+   ╭─[misc/fail/oxc-5955-3.ts:2:18]
+ 1 │ class A {
+ 2 │     [key: string]?: number;
+   ·                  ─
+ 3 │ }
+   ╰────
+
   × The keyword 'let' is reserved
    ╭─[misc/fail/oxc.js:3:1]
  2 │ 

tasks/coverage/snapshots/semantic_misc.snap

@@ -1,6 +1,6 @@
 semantic_misc Summary:
-AST Parsed     : 29/29 (100.00%)
-Positive Passed: 17/29 (58.62%)
+AST Parsed     : 30/30 (100.00%)
+Positive Passed: 17/30 (56.67%)
 tasks/coverage/misc/pass/babel-16776-m.js
 semantic error: Symbol flags mismatch:
 after transform: SymbolId(0): SymbolFlags(FunctionScopedVariable | Export)
@@ -176,6 +176,14 @@ Scope children mismatch:
 after transform: ScopeId(0): [ScopeId(1), ScopeId(2)]
 rebuilt        : ScopeId(0): [ScopeId(1)]
 
+tasks/coverage/misc/pass/oxc-5955.ts
+semantic error: Bindings mismatch:
+after transform: ScopeId(0): ["B", "C", "a"]
+rebuilt        : ScopeId(0): ["B", "a"]
+Scope children mismatch:
+after transform: ScopeId(0): [ScopeId(1), ScopeId(2), ScopeId(3)]
+rebuilt        : ScopeId(0): [ScopeId(1), ScopeId(2)]
+
 tasks/coverage/misc/pass/swc-7187.ts
 semantic error: Bindings mismatch:
 after transform: ScopeId(0): ["K"]

tasks/coverage/snapshots/transformer_misc.snap

@@ -1,3 +1,3 @@
 transformer_misc Summary:
-AST Parsed     : 29/29 (100.00%)
-Positive Passed: 29/29 (100.00%)
+AST Parsed     : 30/30 (100.00%)
+Positive Passed: 30/30 (100.00%)