Fix unnecessary tuple conversion

Author: rodiazet

libsolidity/ast/Types.cpp

@@ -2766,7 +2766,20 @@ std::string TupleType::richIdentifier() const
 bool TupleType::operator==(Type const& _other) const
 {
 	if (auto tupleType = dynamic_cast<TupleType const*>(&_other))
-		return components() == tupleType->components();
+	{
+		if (components().size() != tupleType->components().size())
+			return false;
+
+		for (size_t i = 0; i < components().size(); ++i)
+		{
+			if (components()[i] && tupleType->components()[i] && *components()[i] != *tupleType->components()[i])
+				return false;
+			else if (components()[i] != tupleType->components()[i])
+				return false;
+		}
+
+		return true;
+	}
 	else
 		return false;
 }

test/cmdlineTests/~no_conversion_of_equal_tuple_types/input.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity >= 0.0.0;
+
+contract C {
+    function g_int(uint[] calldata a) public pure returns(uint[] memory, uint[] calldata) {
+        uint[] memory ops1; // we take two arrays so the compiler won't short-circuit the conditional
+        uint[] memory ops2;
+
+        (uint[] memory a1, uint[] calldata b1) = true ? (ops1, a) : (ops2, a);
+
+        return (a1, b1);
+    }
+}

test/cmdlineTests/~no_conversion_of_equal_tuple_types/test.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+import subprocess
+from pathlib import Path
+from textwrap import dedent
+
+# pylint: disable=wrong-import-position
+PROJECT_ROOT = Path(__file__).parents[3]
+sys.path.insert(0, str(PROJECT_ROOT / 'scripts'))
+
+from common.cmdline_helpers import add_preamble
+from common.cmdline_helpers import inside_temporary_dir
+from common.cmdline_helpers import save_bytecode
+from common.cmdline_helpers import solc_bin_report
+from common.git_helpers import git_diff
+from splitSources import split_sources
+
+
+@inside_temporary_dir(Path(__file__).parent.name)
+def test_no_convert_fun_generated():
+    source_file_path = Path(__file__).parent / 'input.sol'
+    add_preamble(Path.cwd())
+
+    solc_binary = os.environ.get('SOLC')
+    if solc_binary is None:
+        raise RuntimeError(dedent("""\
+            `solc` compiler not found.
+            Please ensure you set the SOLC environment variable
+            with the correct path to the compiler's binary.
+        """))
+
+    output = subprocess.check_output(
+        [solc_binary]
+        + [source_file_path]
+        + (["--ir"])
+        + (["--optimize"]),
+        encoding="utf8",
+    )
+
+    # This test verifies that the compiler does not generate a function converting between tuples of the same types.
+    assert "function convert_" not in output, "Output should not contain 'function convert_*'"
+
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(test_no_convert_fun_generated())