ImplicitRules maintains a mapping of initial character of an identifier
to its implicit type.
ImplicitRulesVisitor visits the ImplicitStmt and related parse tree
nodes and updates the rules.
Emit errors messages in these cases:
- implicit type specified more than once for a letter
- IMPLICIT statement and IMPLICIT NONE in same scope
- IMPLICIT statement and IMPLICIT NONE(TYPE) in same scope
- more than one IMPLICIT NONE in a scope
- IMPLICIT statement with empty range of letters
- IMPLICIT NONE statement after PARAMETER statement
- TYPE or EXTERNAL repeated in an IMPLICIT NONE statement
Also start emitting error messages through the parser::Messages
interface. An instance of Messages is created from the cooked source and
saved in the MessageHandler class. It tracks the source location of the
current statement and provides a way to emit messages associated with
that statement.
Original-commit: flang-compiler/f18@e12fea9850
Reviewed-on: https://github.com/flang-compiler/f18/pull/41
Tree-same-pre-rewrite: false
da414d7c3f