[Frontend] Add import decl loc to messages from -Rmodule-loading

Author: xymus

include/swift/AST/DiagnosticsSema.def

@@ -909,7 +909,7 @@ REMARK(cross_import_added,none,
        (Identifier, Identifier, Identifier))
 
 REMARK(module_loaded,none,
-       "loaded module from %0",
+       "loaded module at %0",
        (StringRef))
 
 // Operator decls

lib/AST/ASTContext.cpp

@@ -1922,7 +1922,7 @@ ASTContext::getModule(ImportPath::Module ModulePath) {
   for (auto &importer : getImpl().ModuleLoaders) {
     if (ModuleDecl *M = importer->loadModule(moduleID.Loc, ModulePath)) {
       if (LangOpts.EnableModuleLoadingRemarks) {
-        Diags.diagnose(nullptr,
+        Diags.diagnose(ModulePath.getSourceRange().Start,
                        diag::module_loaded,
                        M->getModuleFilename());
       }

test/ModuleInterface/loading-remarks.swift

@@ -9,6 +9,6 @@
 // RUN: %target-swift-frontend -typecheck %s -I %t -Rmodule-loading 2>&1 | %FileCheck %s
 
 import TestModule
-// CHECK: remark: loaded module from {{.*}}SwiftShims-{{.*}}.pcm
-// CHECK: remark: loaded module from {{.*}}Swift.swiftmodule{{.*}}.swiftmodule
-// CHECK: remark: loaded module from {{.*}}TestModule.swiftinterface
+// CHECK: remark: loaded module at {{.*}}SwiftShims-{{.*}}.pcm
+// CHECK: remark: loaded module at {{.*}}Swift.swiftmodule{{.*}}.swiftmodule
+// CHECK: remark: loaded module at {{.*}}TestModule.swiftinterface