refactor

func AddImport ¶

func AddImport(info *types.Info, file *ast.File, preferredName, pkgpath, member string, pos token.Pos) (prefix string, edits []analysis.TextEdit)

AddImport returns the prefix (either "pkg." or "") that should be used to qualify references to the desired symbol (member) imported from the specified package, plus any necessary edits to the file's import declaration to add a new import.

If the import already exists, and is accessible at pos, AddImport returns the existing name and no edits. (If the existing import is a dot import, the prefix is "".)

Otherwise, it adds a new import, using a local name derived from the preferred name. To request a blank import, use a preferredName of "_", and discard the prefix result; member is ignored in this case.

AddImport accepts the caller's implicit claim that the imported package declares member.

AddImport does not mutate its arguments.

func DeleteDecl ¶

func DeleteDecl(tokFile *token.File, curDecl inspector.Cursor) []analysis.TextEdit

DeleteDecl returns edits to delete the ast.Decl identified by curDecl.

TODO(adonovan): add test suite.

func DeleteSpec ¶

func DeleteSpec(tokFile *token.File, curSpec inspector.Cursor) []analysis.TextEdit

DeleteSpec returns edits to delete the {Type,Value}Spec identified by curSpec.

TODO(adonovan): add test suite. Test for consts as well.

func DeleteStmt ¶

func DeleteStmt(file *token.File, curStmt inspector.Cursor) []analysis.TextEdit

DeleteStmt returns the edits to remove the ast.Stmt identified by curStmt if it recognizes the context. It returns nil otherwise. TODO(pjw, adonovan): it should not return nil, it should return an error

DeleteStmt is called with just the AST so it has trouble deciding if a comment is associated with the statement to be deleted. For instance,

for /*A*/ init()/*B*/;/*C/cond()/*D/;/*E*/post() /*F*/ { /*G*/}

comment B and C are indistinguishable, as are D and E. That is, as the AST does not say where the semicolons are, B and C could go either with the init() or the cond(), so cannot be removed safely. The same is true for D, E, and the post(). (And there are other similar cases.) But the other comments can be removed as they are unambiguously associated with the statement being deleted. In particular, it removes whole lines like

stmt // comment

func DeleteUnusedVars ¶ added in v0.39.0

func DeleteUnusedVars(index *typeindex.Index, info *types.Info, tokFile *token.File, curDelend inspector.Cursor) []analysis.TextEdit

DeleteUnusedVars computes the edits required to delete the declarations of any local variables whose last uses are in the curDelend subtree, which is about to be deleted.

func DeleteVar ¶

func DeleteVar(tokFile *token.File, info *types.Info, curId inspector.Cursor) []analysis.TextEdit

DeleteVar returns edits to delete the declaration of a variable or constant whose defining identifier is curId.

It handles variants including: - GenDecl > ValueSpec versus AssignStmt; - RHS expression has effects, or not; - entire statement/declaration may be eliminated; and removes associated comments.

If it cannot make the necessary edits, such as for a function parameter or result, it returns nil.

func FreshName ¶

func FreshName(scope *types.Scope, pos token.Pos, preferred string) string

FreshName returns the name of an identifier that is undefined at the specified position, based on the preferred name.

TODO(adonovan): refine this to choose a fresh name only when there would be a conflict with the existing declaration: it's fine to redeclare a name in a narrower scope so long as there are no free references to the outer name from within the narrower scope.