fix: generate tmp variables for safe navigation on binary/ternary/unary expressions (#16)

needs_temporary_in_safe_access() in expand_safe_reads was missing match
arms for IrExpression::Binary, Ternary, Not, and Unary. When a safe
property read like (pipeBind(...) || fallback)?.name had a Binary
receiver, the function fell through to `_ => false` instead of recursing
into operands to detect the pipe binding. This caused the pipe to be
evaluated twice with inflated binding slot indices.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: Brooooooklyn

crates/oxc_angular_compiler/src/pipeline/phases/expand_safe_reads.rs

@@ -174,6 +174,20 @@ fn needs_temporary_in_safe_access(expr: &IrExpression<'_>) -> bool {
             needs_temporary_in_safe_access(&keyed.receiver)
                 || needs_temporary_in_safe_access(&keyed.key)
         }
+        // Binary operators need to check both operands
+        IrExpression::Binary(bin) => {
+            needs_temporary_in_safe_access(&bin.lhs) || needs_temporary_in_safe_access(&bin.rhs)
+        }
+        // Ternary needs to check all branches
+        IrExpression::Ternary(ternary) => {
+            needs_temporary_in_safe_access(&ternary.condition)
+                || needs_temporary_in_safe_access(&ternary.true_expr)
+                || needs_temporary_in_safe_access(&ternary.false_expr)
+        }
+        // Not expression needs to check operand
+        IrExpression::Not(not) => needs_temporary_in_safe_access(&not.expr),
+        // Unary operator needs to check operand
+        IrExpression::Unary(unary) => needs_temporary_in_safe_access(&unary.expr),
         // Check AST expressions for function calls
         IrExpression::Ast(ast_expr) => needs_temporary_in_ast_expression(ast_expr),
         // Parenthesized expressions need to check their inner expression

crates/oxc_angular_compiler/tests/integration_test.rs

@@ -1156,6 +1156,20 @@ fn test_safe_call_in_listener_inside_conditional() {
     insta::assert_snapshot!("safe_call_in_listener_inside_conditional", js);
 }
 
+#[test]
+fn test_pipe_in_binary_with_safe_property_read() {
+    // Pattern from EmailCommentComponent: (comment$ | async || comment)?.new_mentioned_thread_count
+    // When a pipe binding is inside a binary expression that is the receiver of a safe property read,
+    // the compiler must generate a temporary variable to avoid evaluating the pipe twice.
+    // TypeScript Angular compiler produces: (tmp = pipeBind(...) || fallback) == null ? null : tmp.prop
+    // Without the fix, OXC duplicates the pipe call in both the guard and the access expression.
+    let js = compile_template_to_js(
+        r#"<div>{{ ((data$ | async) || fallback)?.name }}</div>"#,
+        "TestComponent",
+    );
+    insta::assert_snapshot!("pipe_in_binary_with_safe_property_read", js);
+}
+
 // ============================================================================
 // Event Modifier Tests
 // ============================================================================

crates/oxc_angular_compiler/tests/snapshots/integration_test__pipe_in_binary_with_safe_property_read.snap

@@ -0,0 +1,18 @@
+---
+source: crates/oxc_angular_compiler/tests/integration_test.rs
+assertion_line: 1170
+expression: js
+---
+function TestComponent_Template(rf,ctx) {
+  if ((rf & 1)) {
+    i0.ɵɵelementStart(0,"div");
+    i0.ɵɵtext(1);
+    i0.ɵɵpipe(2,"async");
+    i0.ɵɵelementEnd();
+  }
+  if ((rf & 2)) {
+    let tmp_0_0;
+    i0.ɵɵadvance();
+    i0.ɵɵtextInterpolate((((tmp_0_0 = (i0.ɵɵpipeBind1(2,1,ctx.data$) || ctx.fallback)) == null)? null: tmp_0_0.name));
+  }
+}