fix(sema): reject address.transfer / address.send on Soroban target

src/sema/expression/function_call.rs

@@ -1305,6 +1305,20 @@ fn try_type_method(
                     return Err(());
                 }
 
+                if ns.target == Target::Soroban {
+                    diagnostics.push(Diagnostic::error(
+                        *loc,
+                        format!(
+                            "method '{}' is not available on Soroban. Soroban contracts \
+                        do not have a native value-transfer model; move assets through \
+                        the Stellar Asset Contract (SAC) or the token interface instead.",
+                            func.name
+                        ),
+                    ));
+
+                    return Err(());
+                }
+
                 if !is_payable {
                     diagnostics.push(Diagnostic::error(
                         *loc,

tests/soroban_testcases/mod.rs

@@ -22,3 +22,4 @@ mod timestamp;
 mod token;
 mod ttl;
 mod unsupported_parameters;
+mod value_transfer;

tests/soroban_testcases/value_transfer.rs

@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use solang::codegen::Options;
+use solang::file_resolver::FileResolver;
+use solang::sema::ast::Namespace;
+use solang::{compile, Target};
+use solang_parser::diagnostics::Level;
+use std::ffi::OsStr;
+
+fn compile_soroban(src: &str) -> Namespace {
+    let tmp_file = OsStr::new("test.sol");
+    let mut cache = FileResolver::default();
+    cache.set_file_contents(tmp_file.to_str().unwrap(), src.to_string());
+    let opt = inkwell::OptimizationLevel::Default;
+
+    let (_, ns) = compile(
+        tmp_file,
+        &mut cache,
+        Target::Soroban,
+        &Options {
+            opt_level: opt.into(),
+            log_runtime_errors: true,
+            log_prints: true,
+            #[cfg(feature = "wasm_opt")]
+            wasm_opt: Some(contract_build::OptimizationPasses::Z),
+            soroban_version: None,
+            ..Default::default()
+        },
+        std::vec!["unknown".to_string()],
+        "0.0.1",
+    );
+
+    ns
+}
+
+// Regression test for https://github.com/hyperledger-solang/solang/issues/1909
+// Previously this would panic in codegen (`Found IntValue` at
+// `src/emit/instructions.rs:989`) while lowering `Instr::ValueTransfer`. Soroban
+// has no native value-transfer model, so the call should be rejected at sema
+// time with an actionable diagnostic.
+#[test]
+fn address_transfer_is_rejected_on_soroban() {
+    let ns = compile_soroban(
+        r#"
+        contract C {
+            function run() external payable {
+                payable(address(this)).transfer(uint256(0));
+            }
+        }
+        "#,
+    );
+
+    let errors = ns
+        .diagnostics
+        .iter()
+        .filter(|diagnostic| diagnostic.level == Level::Error)
+        .collect::<Vec<_>>();
+
+    assert!(
+        errors
+            .iter()
+            .any(|diagnostic| diagnostic.message
+                == "method 'transfer' is not available on Soroban. Soroban contracts \
+                    do not have a native value-transfer model; move assets through \
+                    the Stellar Asset Contract (SAC) or the token interface instead."),
+        "expected a Soroban-specific rejection of `transfer`, got: {errors:?}",
+    );
+}
+
+#[test]
+fn address_send_is_rejected_on_soroban() {
+    let ns = compile_soroban(
+        r#"
+        contract C {
+            function run() external payable {
+                payable(address(this)).send(uint256(0));
+            }
+        }
+        "#,
+    );
+
+    let errors = ns
+        .diagnostics
+        .iter()
+        .filter(|diagnostic| diagnostic.level == Level::Error)
+        .collect::<Vec<_>>();
+
+    assert!(
+        errors
+            .iter()
+            .any(|diagnostic| diagnostic.message
+                == "method 'send' is not available on Soroban. Soroban contracts \
+                    do not have a native value-transfer model; move assets through \
+                    the Stellar Asset Contract (SAC) or the token interface instead."),
+        "expected a Soroban-specific rejection of `send`, got: {errors:?}",
+    );
+}