Add compile-time support for dict.values (#2661)

* Implement `dict.values` for `DictConstant`

* Tests: Add tests

* Tests: Fix typing mistake

* Tests: Update references

* Uncomment check for modifying attribute

* Tests: Update references

* Delete tests/reference/asr-func_04-eef2656.stdout

* Tests: Move `print` before `assert`

* Tests: Update test

Author: kmr-srbh

integration_tests/test_dict_keys_values.py

@@ -74,4 +74,26 @@ def test_dict_keys_values():
     assert len(k_2) == 3
 
 
+    # dict.values on dict constant
+    print({1: "a"}.values())
+    assert len({1: "a"}.values()) == 1
+
+    print({"a": 1, "b": 2, "c": 3}.values())
+    assert len({"a": 1, "b": 2, "c": 3}.values()) == 3
+
+    print({1: [1, 2, 3], 2: [4, 5, 6], 3: [7, 8, 9]}.values())
+    assert len({1: [1, 2, 3], 2: [4, 5, 6], 3: [7, 8, 9]}.values()) == 3
+
+    print({(1, 2): "a", (3, 4): "b", (5, 6): "c"}.values())
+    assert len({(1, 2): "a", (3, 4): "b", (5, 6): "c"}.values()) == 3
+
+    v_1: list[list[i32]] = {"list1": [1, 2, 3], "list2": [4, 5, 6], "list3": [7, 8, 9]}.values()
+    print(v_1)
+    assert len(v_1) == 3
+
+    v_2: list[str] = {(1, 2): "a", (3, 4): "b", (5, 6): "c"}.values()
+    print(v_2)
+    assert len(v_2) == 3
+
+
 test_dict_keys_values()

src/libasr/pass/intrinsic_functions.h

@@ -4786,10 +4786,15 @@ static inline void verify_args(const ASR::IntrinsicElementalFunction_t& x, diag:
         x.base.base.loc, diagnostics);
 }
 
-static inline ASR::expr_t *eval_dict_values(Allocator &/*al*/,
-    const Location &/*loc*/, ASR::ttype_t *, Vec<ASR::expr_t*>& /*args*/, diag::Diagnostics& /*diag*/) {
-    // TODO: To be implemented for DictConstant expression
-    return nullptr;
+static inline ASR::expr_t *eval_dict_values(Allocator &al,
+    const Location &loc, ASR::ttype_t *t, Vec<ASR::expr_t*>& args, diag::Diagnostics& /*diag*/) {
+        if (args[0] == nullptr) {
+            return nullptr;
+        }
+        ASR::DictConstant_t* cdict = ASR::down_cast<ASR::DictConstant_t>(args[0]);
+
+        return ASRUtils::EXPR(ASR::make_ListConstant_t(al, loc,
+            cdict->m_values, cdict->n_values, t));
 }
 
 static inline ASR::asr_t* create_DictValues(Allocator& al, const Location& loc,