From 338f77fa81c19a7f6f2396496ac8ed645efd47c1 Mon Sep 17 00:00:00 2001
From: BobTheBuidler <70677534+BobTheBuidler@users.noreply.github.com>
Date: Wed, 15 Oct 2025 16:59:08 -0400
Subject: [PATCH 1/4] [mypyc] feat: use `get_expr_length_value` in
 `translate_len`

Currently, `translate_len` can determine the length of an RTuple at compile time

This PR extends this capability to all expressions supported by `get_expr_length_value`
---
 mypyc/irbuild/specialize.py | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/mypyc/irbuild/specialize.py b/mypyc/irbuild/specialize.py
index e810f11bd079..a7b067b98549 100644
--- a/mypyc/irbuild/specialize.py
+++ b/mypyc/irbuild/specialize.py
@@ -69,6 +69,7 @@
     is_int64_rprimitive,
     is_int_rprimitive,
     is_list_rprimitive,
+    is_sequence_rprimitive,
     is_uint8_rprimitive,
     list_rprimitive,
     object_rprimitive,
@@ -221,17 +222,11 @@ def translate_len(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value
     if len(expr.args) == 1 and expr.arg_kinds == [ARG_POS]:
         arg = expr.args[0]
         expr_rtype = builder.node_type(arg)
-        if isinstance(expr_rtype, RTuple):
-            # len() of fixed-length tuple can be trivially determined
-            # statically, though we still need to evaluate it.
-            builder.accept(arg)
-            return Integer(len(expr_rtype.types))
+        # NOTE (?) I'm not sure if my handling of can_borrow is correct here
+        obj = builder.accept(arg, can_borrow=is_list_rprimitive(expr_rtype))
+        if is_sequence_rprimitive(expr_rtype) or isinstance(expr_rtype, RTuple):
+            return get_expr_length_value(builder, arg, obj, expr.line, use_pyssize_t=False)
         else:
-            if is_list_rprimitive(builder.node_type(arg)):
-                borrow = True
-            else:
-                borrow = False
-            obj = builder.accept(arg, can_borrow=borrow)
             return builder.builtin_len(obj, expr.line)
     return None
 

From 0c7974823566057575fa2edd5e389b8cd31fbf5d Mon Sep 17 00:00:00 2001
From: BobTheBuidler <70677534+BobTheBuidler@users.noreply.github.com>
Date: Wed, 15 Oct 2025 17:00:06 -0400
Subject: [PATCH 2/4] Update specialize.py

---
 mypyc/irbuild/specialize.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mypyc/irbuild/specialize.py b/mypyc/irbuild/specialize.py
index a7b067b98549..39bcbc708e3e 100644
--- a/mypyc/irbuild/specialize.py
+++ b/mypyc/irbuild/specialize.py
@@ -81,6 +81,7 @@
 from mypyc.irbuild.constant_fold import constant_fold_expr
 from mypyc.irbuild.for_helpers import (
     comprehension_helper,
+    get_expr_length_value,
     sequence_from_generator_preallocate_helper,
     translate_list_comprehension,
     translate_set_comprehension,

From f78c7542a770a09d842a46974cdbbf5d2b2a923f Mon Sep 17 00:00:00 2001
From: BobTheBuidler <70677534+BobTheBuidler@users.noreply.github.com>
Date: Wed, 15 Oct 2025 18:52:19 -0400
Subject: [PATCH 3/4] Update irbuild-basic.test

---
 mypyc/test-data/irbuild-basic.test | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mypyc/test-data/irbuild-basic.test b/mypyc/test-data/irbuild-basic.test
index 612f3266fd79..fd5f1411c3a7 100644
--- a/mypyc/test-data/irbuild-basic.test
+++ b/mypyc/test-data/irbuild-basic.test
@@ -3799,3 +3799,11 @@ L0:
     r2.__mypyc_env__ = r0; r3 = is_error
     wrapper = r2
     return wrapper
+
+[case testStaticLength]
+def get_length() -> int:
+    return len("https://w3id.org/cwl/salad#")
+[out]
+def get_length():
+L0:
+    return 27

From 7f7934637108d61f80b9604426a669535d2d94de Mon Sep 17 00:00:00 2001
From: BobTheBuidler <70677534+BobTheBuidler@users.noreply.github.com>
Date: Wed, 15 Oct 2025 19:23:29 -0400
Subject: [PATCH 4/4] Update irbuild-basic.test

---
 mypyc/test-data/irbuild-basic.test | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mypyc/test-data/irbuild-basic.test b/mypyc/test-data/irbuild-basic.test
index fd5f1411c3a7..e7074b13fe13 100644
--- a/mypyc/test-data/irbuild-basic.test
+++ b/mypyc/test-data/irbuild-basic.test
@@ -3805,5 +3805,7 @@ def get_length() -> int:
     return len("https://w3id.org/cwl/salad#")
 [out]
 def get_length():
+    r0 :: str
 L0:
-    return 27
+    r0 = 'https://w3id.org/cwl/salad#'
+    return 54