Fixing version issue

Author: grantnelson-wf

compiler/astutil/astutil.go

@@ -492,8 +492,6 @@ func FinalizeRemovals(file *ast.File) {
 //     build constraints or any file level directives, but simply append
 //     the tail comments as is. This may cause issues when formatting
 //     the resulting file including extra newlines or invalid code.
-//   - The file end will be set to the end of the last tail file that
-//     will be from a different file according to the FileSet.
 func ConcatenateFiles(file *ast.File, tails ...*ast.File) error {
 	// Populate the imports map from the target file.
 	// This map will be used to check for duplicate imports.
@@ -518,15 +516,6 @@ func ConcatenateFiles(file *ast.File, tails ...*ast.File) error {
 			return fmt.Errorf("can not concatenate files with different package names: %q != %q", file.Name.Name, tail.Name.Name)
 		}
 
-		// Check go version from build constraints, e.g. `//go:build go1.18`
-		// We probably could merge different versions of Go,
-		// but it's better to know when it happens and handle it.
-		if len(file.GoVersion) == 0 {
-			file.GoVersion = tail.GoVersion
-		} else if len(tail.GoVersion) > 0 && file.GoVersion != tail.GoVersion {
-			return fmt.Errorf("can not concatenate files with different Go versions: %q != %q", file.GoVersion, tail.GoVersion)
-		}
-
 		// Concatenate the imports.
 		for _, imp := range tail.Imports {
 			path := imp.Path.Value
@@ -560,9 +549,6 @@ func ConcatenateFiles(file *ast.File, tails ...*ast.File) error {
 			file.Package = tail.Package
 			file.Name.NamePos = tail.Name.NamePos
 		}
-
-		// Update the file end to the new end.
-		file.FileEnd = tail.FileEnd
 	}
 
 	// Update the target file's declarations with all the imports

compiler/astutil/astutil_test.go

@@ -1058,17 +1058,6 @@ func TestConcatenateFiles(t *testing.T) {
 			srcTail: `package otherTestPackage
 					func bar() {}`,
 			expErr: `can not concatenate files with different package names: "testpackage" != "otherTestPackage"`,
-		}, {
-			name: `packages with go versions`,
-			srcHead: `//go:build go1.18
-			
-					package testpackage
-					func foo() {}`,
-			srcTail: `//go:build go1.20
-			
-					package testpackage
-					func bar() {}`,
-			expErr: `can not concatenate files with different Go versions: "go1.18" != "go1.20"`,
 		}, {
 			name: `import mismatch with one named`,
 			srcHead: `package testpackage