feat: Provide a more precise error message when missed return statement is inside branch

[nicolaassolini-qntm]

• The build function in builder.py now locates the specific statement and branch condition where a return statement is missing
• The ExpectedError class now includes a Branch note
• New test cases are added to ensure correct error reporting for missing returns in various branching scenarios

close #1348

[github-actions]

Bencher Report

Branch	na/issue1348-error-message-for-missing-return
Testbed	Linux

🚨 6 Alerts

Benchmark	Measure Units	View	Benchmark Result (Result Δ%)	Upper Boundary (Limit %)
tests/benchmarks/test_big_array.py::test_big_array_check	Latency milliseconds (ms)	📈 plot 🚷 threshold 🚨 alert (🔔)	724.69 ms (+15.59%) Baseline: 626.93 ms	658.28 ms (110.09%)
tests/benchmarks/test_big_array.py::test_big_array_compile	Latency seconds (s)	📈 plot 🚷 threshold 🚨 alert (🔔)	1.96 s (+22.90%) Baseline: 1.60 s	1.68 s (117.05%)
tests/benchmarks/test_big_array.py::test_big_array_executable	Latency seconds (s)	📈 plot 🚷 threshold 🚨 alert (🔔)	8.16 s (+16.23%) Baseline: 7.02 s	7.37 s (110.69%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_check	Latency milliseconds (ms)	📈 plot 🚷 threshold 🚨 alert (🔔)	50.55 ms (+10.27%) Baseline: 45.84 ms	48.13 ms (105.02%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_executable	Latency milliseconds (ms)	📈 plot 🚷 threshold 🚨 alert (🔔)	612.26 ms (+15.87%) Baseline: 528.41 ms	554.83 ms (110.35%)
tests/benchmarks/test_prelude.py::test_import_guppy	Latency microseconds (µs)	📈 plot 🚷 threshold 🚨 alert (🔔)	51.42 µs (+24.91%) Baseline: 41.16 µs	43.22 µs (118.96%)

Click to view all benchmark results

Benchmark	Latency	Benchmark Result microseconds (µs) (Result Δ%)	Upper Boundary microseconds (µs) (Limit %)
tests/benchmarks/test_big_array.py::test_big_array_check	📈 view plot 🚷 view threshold 🚨 view alert (🔔)	724,690.82 µs (+15.59%) Baseline: 626,929.26 µs	658,275.72 µs (110.09%)
tests/benchmarks/test_big_array.py::test_big_array_compile	📈 view plot 🚷 view threshold 🚨 view alert (🔔)	1,961,315.77 µs (+22.90%) Baseline: 1,595,852.59 µs	1,675,645.22 µs (117.05%)
tests/benchmarks/test_big_array.py::test_big_array_executable	📈 view plot 🚷 view threshold 🚨 view alert (🔔)	8,155,660.04 µs (+16.23%) Baseline: 7,017,018.16 µs	7,367,869.07 µs (110.69%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_check	📈 view plot 🚷 view threshold 🚨 view alert (🔔)	50,547.73 µs (+10.27%) Baseline: 45,838.95 µs	48,130.90 µs (105.02%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_compile	📈 view plot 🚷 view threshold	110,151.43 µs (-43.93%) Baseline: 196,442.77 µs	206,264.91 µs (53.40%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_executable	📈 view plot 🚷 view threshold 🚨 view alert (🔔)	612,260.06 µs (+15.87%) Baseline: 528,407.93 µs	554,828.32 µs (110.35%)
tests/benchmarks/test_prelude.py::test_import_guppy	📈 view plot 🚷 view threshold 🚨 view alert (🔔)	51.42 µs (+24.91%) Baseline: 41.16 µs	43.22 µs (118.96%)

🐰 View full continuous benchmarking report in Bencher

[github-actions]

Bencher Report

Branch	na/issue1348-error-message-for-missing-return
Testbed	Linux

Click to view all benchmark results

Benchmark	hugr_bytes	Benchmark Result bytes x 1e3 (Result Δ%)	Upper Boundary bytes x 1e3 (Limit %)	hugr_nodes	Benchmark Result nodes (Result Δ%)	Upper Boundary nodes (Limit %)
tests/benchmarks/test_big_array.py::test_big_array_compile	📈 view plot 🚷 view threshold	140.94 x 1e3 (0.00%) Baseline: 140.94 x 1e3	142.35 x 1e3 (99.01%)	📈 view plot 🚷 view threshold	6,592.00 (0.00%) Baseline: 6,592.00	6,657.92 (99.01%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_compile	📈 view plot 🚷 view threshold	18.59 x 1e3 (0.00%) Baseline: 18.59 x 1e3	18.78 x 1e3 (99.01%)	📈 view plot 🚷 view threshold	608.00 (0.00%) Baseline: 608.00	614.08 (99.01%)

🐰 View full continuous benchmarking report in Bencher

[codecov-commenter]

Codecov Report

❌ Patch coverage is 97.22222% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 93.39%. Comparing base (2ba5720) to head (9d0755d).
⚠️ Report is 37 commits behind head on main.

Files with missing lines	Patch %	Lines
...g-internals/src/guppylang_internals/cfg/builder.py	96.15%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1486      +/-   ##
==========================================
- Coverage   93.54%   93.39%   -0.15%     
==========================================
  Files         127      128       +1     
  Lines       11797    12004     +207     
==========================================
+ Hits        11035    11211     +176     
- Misses        762      793      +31     

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[nicolaassolini-qntm]

I have refactored the error point search; it should be better now. I also added a couple of extra test cases

[nicolaassolini-qntm]

I also moved the test files to misc_errors

[mark-koch]

Thanks, the new algorithm is looking a lot better! Also sorry for the long delay in getting back to you 😅

[mark-koch]

Why is it always 0 here?

[nicolaassolini-qntm]

Because if the return is inside the loop, the best suggestion we suggest to add a return when the loop condition is false. Added in the comment explanation.

[mark-koch]

Thanks, looks good to me!