A rest parameter of a primitive type is an error at the parameter

tslang/lib/TypeScript/MLIRGenFunctions.cpp

@@ -342,6 +342,18 @@ namespace mlirgen
                 return {mlir::failure(), isGenericTypes, params};
             }
 
+            // the arguments a rest parameter takes are put in an array: one of a number type only
+            // failed the module's verification
+            auto restBaseType = mth.getBaseType(type);
+            if (isMultiArgs
+                && (mth.isNumericType(restBaseType) || isa<mlir_ts::StringType>(restBaseType)
+                    || isa<mlir_ts::BooleanType>(restBaseType) || isa<mlir_ts::BigIntType>(restBaseType)
+                    || isa<mlir_ts::CharType>(restBaseType)))
+            {
+                emitError(loc(arg)) << "A rest parameter must be of an array type, not '" << to_print(type) << "'";
+                return {mlir::failure(), isGenericTypes, params};
+            }
+
             if (isBindingPattern)
             {
                 params.push_back(

tslang/test/tester/CMakeLists.txt

@@ -2666,6 +2666,16 @@ foreach(ownership_shard RANGE ${ownership_last})
                      -P "${CMAKE_CURRENT_SOURCE_DIR}/verify-ownership.cmake")
 endforeach()
 
+# A rest parameter of a number, string or boolean type is an error at the parameter: it reached the
+# MLIR verifier, which failed the module at 1:1.
+add_test(NAME test-compile-diagnostic-location-rest-parameter-type
+         COMMAND $<TARGET_FILE:tslang> --emit=obj --no-default-lib -mm=none
+                 "${PROJECT_SOURCE_DIR}/test/tester/diagnostic-location/rest_parameter_type.ts"
+                 -o "${CMAKE_CURRENT_BINARY_DIR}/diagnostic-location-rest-parameter-type.obj")
+set_tests_properties(test-compile-diagnostic-location-rest-parameter-type
+                     PROPERTIES PASS_REGULAR_EXPRESSION "rest_parameter_type\\.ts:6:12: error: A rest parameter must be of an array type, not 's32'"
+                                FAIL_REGULAR_EXPRESSION "Stack dump|Assertion failed|rest_parameter_type\\.ts:1:|rest_parameter_type\\.ts:4:|verification")
+
 # A call with fewer arguments than the callee's required parameters is an error (TS2554),
 # not padded with undef. Each file in call-arity/ makes one bad call; the test passes when
 # the compiler prints the expected message. The counts are what the user wrote, so `this`

tslang/test/tester/diagnostic-location/rest_parameter_type.ts

@@ -0,0 +1,11 @@
+// A rest parameter of a number type reached the MLIR verifier, which reported the array made
+// of the arguments at the call and the module at 1:1.
+
+function sum(...a: int[]) {}
+
+function f(...a: int) {}
+
+function main() {
+    sum(1, 2);
+    f(1, 2);
+}