ParseFile parses the source code of a single Go source file and returns the corresponding ast.File node. The source code may be provided via the filename of the source file, or via the src parameter.

If src != nil, ParseFile parses the source from src and the filename is only used when recording position information. The type of the argument for the src parameter must be string, []byte, or io.Reader. If src == nil, ParseFile parses the file specified by filename.

The mode parameter controls the amount of source text parsed and other optional parser functionality. Position information is recorded in the file set fset, which must not be nil.

If the source couldn't be read, the returned AST is nil and the error indicates the specific failure. If the source was read but syntax errors were found, the result is a partial AST (with ast.Bad* nodes representing the fragments of erroneous source code). Multiple errors are returned via a scanner.ErrorList which is sorted by file position.