A property that does not resolve is named in the error, in a condition too (#442)

tslang/lib/TypeScript/MLIRGenAccessCall.cpp

@@ -424,8 +424,14 @@ namespace mlirgen
             // whole discovery run over that; let the caller treat this as "unknown for
             // now" (same idiom as mlirGenCallExpression's `!result.value &&
             // genContext.allowPartialResolve` case above).
+            //
+            // It still says why: a message is shown only if the module then fails to compile,
+            // and one that does may fail in this very run, before any other run reaches the
+            // access - a function's return type is inferred this way. Without it the only error
+            // was what the caller made of no value, "the condition has no value" in an `if` (#442).
             if (genContext.dummyRun || genContext.allowPartialResolve)
             {
+                emitError(location, "Can't resolve property '") << name << "' of type " << to_print(objectValue.getType());
                 return mlir::success();
             }
 

tslang/test/tester/CMakeLists.txt

@@ -3207,6 +3207,19 @@ foreach(builtin_cast_case ${builtin_cast_cases})
                                     FAIL_REGULAR_EXPRESSION "Stack dump|Assertion failed")
 endforeach()
 
+# A property that does not resolve is named in the error, in a condition too: the run inferring the
+# function's return type gave no value and no message, and an `if` reported only "the condition has
+# no value" (#442).
+foreach(property_error_name if const while conditional)
+    add_test(NAME test-compile-property-error-${property_error_name}
+             COMMAND $<TARGET_FILE:tslang> --emit=obj --no-default-lib -mm=none
+                     "${PROJECT_SOURCE_DIR}/test/tester/property-error/${property_error_name}.ts"
+                     -o "${CMAKE_CURRENT_BINARY_DIR}/property-error-${property_error_name}.obj")
+    set_tests_properties(test-compile-property-error-${property_error_name}
+                         PROPERTIES PASS_REGULAR_EXPRESSION "Can't resolve property 'foo' of type [{]x:s32[}]"
+                                    FAIL_REGULAR_EXPRESSION "Stack dump|Assertion failed")
+endforeach()
+
 # The shared-component tier under the other two models. A shared library records the model
 # it was built under, so both halves of a pair are built with the same flag - which is what
 # these run. The file pairs are the default model's, verbatim.

tslang/test/tester/property-error/conditional.ts

@@ -0,0 +1,7 @@
+// A property that does not resolve is named in the error, wherever it is read (#442): during the
+// run that infers main's return type the access gave no value and said nothing, so an `if` said
+// only "the condition has no value".
+function main() {
+    const o = { x: 1 };
+    print(o.foo ? 1 : 2);
+}

tslang/test/tester/property-error/const.ts

@@ -0,0 +1,8 @@
+// A property that does not resolve is named in the error, wherever it is read (#442): during the
+// run that infers main's return type the access gave no value and said nothing, so an `if` said
+// only "the condition has no value".
+function main() {
+    const o = { x: 1 };
+    const v = o.foo;
+    print(v);
+}

tslang/test/tester/property-error/if.ts

@@ -0,0 +1,7 @@
+// A property that does not resolve is named in the error, wherever it is read (#442): during the
+// run that infers main's return type the access gave no value and said nothing, so an `if` said
+// only "the condition has no value".
+function main() {
+    const o = { x: 1 };
+    if (o.foo) print(1);
+}

tslang/test/tester/property-error/while.ts

@@ -0,0 +1,7 @@
+// A property that does not resolve is named in the error, wherever it is read (#442): during the
+// run that infers main's return type the access gave no value and said nothing, so an `if` said
+// only "the condition has no value".
+function main() {
+    const o = { x: 1 };
+    while (o.foo) print(1);
+}