Add hint for Cpp1 prefix operators (hsutter#419)

Author: ntrel

regression-tests/pure2-cpp1-prefix-expression.cpp2

@@ -0,0 +1,5 @@
+main: () = 
+{
+ v := 1;
+ p := &v;
+}

regression-tests/test-results/pure2-cpp1-prefix-expression.cpp2.output

@@ -0,0 +1,3 @@
+pure2-cpp1-prefix-expression.cpp2...
+pure2-cpp1-prefix-expression.cpp2(4,10): error: use postfix 'var&' for address, not '&var'
+

source/parse.h

@@ -3851,6 +3851,20 @@ class parser
  if ((n->expr = postfix_expression())) {
  return n;
  }
+ switch (curr().type())
+ {
+ break; case lexeme::PlusPlus:
+ error("only postfix 'var++' increment is supported, not '++var'", false);
+ break; case lexeme::MinusMinus:
+ error("only postfix 'var--' decrement is supported, not '--var'", false);
+ break; case lexeme::Multiply:
+ error("use postfix 'ptr*' to dereference, not '*ptr'", false);
+ break; case lexeme::Ampersand:
+ error("use postfix 'var&' for address, not '&var'", false);
+ break; case lexeme::Tilde:
+ error("use postfix 'var~' for bitwise complement, not '~var'", false);
+ break; default: ;
+ }
  return {};
  }