Implement switch statement type checking, interpretation, and tests

src/interpreter/exec_stmt.rs

@@ -34,7 +34,7 @@
 //! This gives MiniC correct lexical block scoping without a scope stack.
 
 use crate::environment::Environment;
-use crate::ir::ast::{CheckedExpr, CheckedStmt, Expr, Statement};
+use crate::ir::ast::{CheckedExpr, CheckedStmt, Expr, Literal, Statement};
 
 use super::eval_expr::{eval_call, eval_expr};
 use super::value::{RuntimeError, Value};
@@ -114,6 +114,7 @@ pub fn exec_stmt(stmt: &CheckedStmt, env: &mut Environment<Value>) -> ExecResult
 
         // --- Switch ---
         Statement::Switch { target, cases, default } => {
+            ensure_unique_switch_labels(cases)?;
             // Avalia o valor da expressão alvo
             let target_val = eval_expr(target, env)?;
 
@@ -295,3 +296,18 @@ fn extract_ident_name(expr: &CheckedExpr) -> Result<String, RuntimeError> {
         )),
     }
 }
+
+fn ensure_unique_switch_labels(
+    cases: &[(Literal, Vec<CheckedStmt>)],
+) -> Result<(), RuntimeError> {
+    for (i, (label, _)) in cases.iter().enumerate() {
+        if cases.iter().skip(i + 1).any(|(other, _)| other == label) {
+            return Err(RuntimeError::new(format!(
+                "duplicate switch case label: {:?}",
+                label
+            )));
+        }
+    }
+
+    Ok(())
+}

src/semantic/type_checker.rs

@@ -253,6 +253,11 @@ fn type_check_stmt(
                 let lit_ty = match lit {
                     Literal::Int(_) => Type::Int,
                     Literal::Bool(_) => Type::Bool,
+                    _ => {
+                        return Err(TypeError::new(
+                            "switch case label must be an Int or Bool literal",
+                        ));
+                    }
                 };
 
             // Garante que o tipo do literal é compatível com o tipo do target

tests/interpreter.rs

@@ -196,6 +196,114 @@ fn test_out_of_bounds() {
     );
 }
 
+// ---------------------------------------------------------------------------
+// 7.10b Switch
+// ---------------------------------------------------------------------------
+#[test]
+fn test_switch_int_case_executes_matching_branch() {
+    let src = r#"
+        int choose(int x) {
+            switch x {
+                case 1: return 10;
+                case 2: return 20;
+                default: return 99;
+            }
+        }
+
+        void main() {
+            int result = choose(2);
+            if result != 20 {
+                int[] arr = [1];
+                int fail = arr[5];
+            }
+        }
+    "#;
+    assert!(run(src).is_ok(), "{}", run(src).unwrap_err());
+}
+
+#[test]
+fn test_switch_int_default_executes_when_no_case_matches() {
+    let src = r#"
+        int choose(int x) {
+            switch x {
+                case 1: return 10;
+                case 2: return 20;
+                default: return 99;
+            }
+        }
+
+        void main() {
+            int result = choose(3);
+            if result != 99 {
+                int[] arr = [1];
+                int fail = arr[5];
+            }
+        }
+    "#;
+    assert!(run(src).is_ok(), "{}", run(src).unwrap_err());
+}
+
+#[test]
+fn test_switch_bool_case_executes_matching_branch() {
+    let src = r#"
+        int choose(bool flag) {
+            switch flag {
+                case true: return 1;
+                case false: return 0;
+                default: return 99;
+            }
+        }
+
+        void main() {
+            int result = choose(false);
+            if result != 0 {
+                int[] arr = [1];
+                int fail = arr[5];
+            }
+        }
+    "#;
+    assert!(run(src).is_ok(), "{}", run(src).unwrap_err());
+}
+
+#[test]
+fn test_switch_assignment_to_outer_variable_persists() {
+    let src = r#"
+        void main() {
+            int result = 0;
+            switch 1 {
+                case 1: result = 10;
+                case 2: result = 20;
+                default: result = 99;
+            }
+
+            if result != 10 {
+                int[] arr = [1];
+                int fail = arr[5];
+            }
+        }
+    "#;
+    assert!(run(src).is_ok(), "{}", run(src).unwrap_err());
+}
+
+#[test]
+fn test_switch_duplicate_case_labels_error() {
+    let src = r#"
+        void main() {
+            switch 1 {
+                case 1: print("one");
+                case 1: print("again");
+                default: print("other");
+            }
+        }
+    "#;
+    let result = run(src);
+    assert!(result.is_err(), "expected duplicate switch case label error");
+    assert!(
+        result.unwrap_err().contains("duplicate switch case label"),
+        "error should mention duplicate switch case label"
+    );
+}
+
 // ---------------------------------------------------------------------------
 // 7.11 Undefined function (caught by type checker)
 // ---------------------------------------------------------------------------