add error check in auth resolver codegen

Author: wty-Bryant

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/AuthParametersResolverGenerator.java

@@ -43,14 +43,14 @@ public GoWriter.Writable generate() {
         loadResolvers();
 
         return goTemplate("""
-                func $name:L(ctx $context:T, operation string, input interface{}, options Options) $params:P {
-                    params := &$params:T{
+                func $name:L(ctx $context:T, operation string, input interface{}, options Options) (params $params:P, err error) {
+                    params = &$params:T{
                         Operation: operation,
                     }
 
                     $bindings:W
-
-                    return params
+                
+                    return
                 }
                 """,
                 MapUtils.of(
@@ -64,7 +64,11 @@ public GoWriter.Writable generate() {
     private GoWriter.Writable generateResolvers() {
         return (writer) -> {
             for (var resolver: resolvers) {
-                writer.write("$T(ctx, params, input, options)", resolver.resolver());
+                if (resolver.resolver().getName().equals("bindAuthEndpointParams")) {
+                    writer.write("err = $T(ctx, params, input, options)", resolver.resolver());
+                } else {
+                    writer.write("$T(ctx, params, input, options)", resolver.resolver());
+                }
             }
         };
     }

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/auth/ResolveAuthSchemeMiddlewareGenerator.java

@@ -70,7 +70,10 @@ private GoWriter.Writable generateBody() {
                 _, span := $3T(ctx, "ResolveAuthScheme")
                 defer span.End()
 
-                params := $1L(ctx, m.operation, getOperationInput(ctx), m.options)
+                params, err := $1L(ctx, m.operation, getOperationInput(ctx), m.options)
+                if err != nil {
+                    return out, metadata, $2T("bind auth scheme params: %w", err)
+                }
                 options, err := m.options.AuthSchemeResolver.ResolveAuthSchemes(ctx, params)
                 if err != nil {
                     return out, metadata, $2T("resolve auth scheme: %w", err)

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/endpoints/EndpointParameterBindingsGenerator.java

@@ -57,8 +57,8 @@ public GoWriter.Writable generate() {
                     bindEndpointParams(*EndpointParameters)
                 }
 
-                func bindEndpointParams(ctx $context:T, input interface{}, options Options) (params *EndpointParameters, err error) {
-                    params = &EndpointParameters{}
+                func bindEndpointParams(ctx $context:T, input interface{}, options Options) (*EndpointParameters, error) {
+                    params := &EndpointParameters{}
                 
                     $builtinBindings:W
 
@@ -68,7 +68,7 @@ func bindEndpointParams(ctx $context:T, input interface{}, options Options) (par
                         b.bindEndpointParams(params)
                     }
 
-                    return
+                    return params, nil
                 }
                 """,
                 MapUtils.of(
@@ -96,7 +96,13 @@ private GoWriter.Writable generateBuiltinBindings() {
             for (var param: boundBuiltins) {
                 String paramName =  EndpointParametersGenerator.getExportedParameterName(param);
                 if (paramName.equals("Region")) {
-                    writer.write("params.Region, err = $W",
+                    writer.write("""
+                                    region, err := $W
+                                    if err != nil {
+                                        return nil, err
+                                    }
+                                    params.Region = region
+                                    """,
                             builtinBindings.get(param.getBuiltIn().get()));
                 } else {
                     writer.write(