compiler: Don't mutate table name (#517)

Author: kyleconroy

internal/compiler/output_columns.go

@@ -126,6 +126,7 @@ func outputColumns(qc *QueryCatalog, node ast.Node) ([]*Column, error) {
 						cols = append(cols, &Column{
 							Name:     cname,
 							Type:     c.Type,
+							Scope:    scope,
 							Table:    c.Table,
 							DataType: c.DataType,
 							NotNull:  c.NotNull,
@@ -262,7 +263,11 @@ func sourceTables(qc *QueryCatalog, node ast.Node) ([]*Table, error) {
 				return nil, cerr
 			}
 			if n.Alias != nil {
-				table.Rel.Name = *n.Alias.Aliasname
+				table.Rel = &ast.TableName{
+					Catalog: table.Rel.Catalog,
+					Schema:  table.Rel.Schema,
+					Name:    *n.Alias.Aliasname,
+				}
 			}
 			tables = append(tables, table)
 		default:

internal/endtoend/testdata/select_distinct/go/db.go

@@ -0,0 +1,5 @@
+CREATE TABLE bar (id serial not null, name text);
+
+-- name: GetBars :many
+SELECT DISTINCT ON (a.id) a.*
+FROM bar a;

internal/endtoend/testdata/select_distinct/go/models.go

@@ -0,0 +1,11 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}