Fix bugzilla 24639 - ImportC: defines of negative constants not detec…

…ted for enum conversion (#16789)

Negative expressions inside parens are already supported. This adds
support for defines with negative numbers without parens, but not more
complex expressions. Defines for negative numbers are often used as
error codes in C.

compiler/src/dmd/cparse.d

@@ -5956,6 +5956,30 @@ final class CParser(AST) : Parser!AST
 
  AST.Type t;
 
+ bool hasMinus;
+ if (token.value == TOK.min)
+ {
+ nextToken();
+ // Only allow integer and float literals after minus.
+ switch (token.value)
+ {
+ case TOK.int32Literal:
+ case TOK.uns32Literal:
+ case TOK.int64Literal:
+ case TOK.uns64Literal:
+ case TOK.float32Literal:
+ case TOK.float64Literal:
+ case TOK.float80Literal:
+ case TOK.imaginary32Literal:
+ case TOK.imaginary64Literal:
+ case TOK.imaginary80Literal:
+ hasMinus = true;
+ break;
+ default:
+ continue;
+ }
+ }
+
  Lswitch:
  switch (token.value)
  {
@@ -5980,6 +6004,8 @@ final class CParser(AST) : Parser!AST
  * enum id = intvalue;
  */
  AST.Expression e = new AST.IntegerExp(scanloc, intvalue, t);
+ if (hasMinus)
+ e = new AST.NegExp(scanloc, e);
  auto v = new AST.VarDeclaration(scanloc, t, id, new AST.ExpInitializer(scanloc, e), STC.manifest);
  addSym(v);
  ++p;
@@ -6003,6 +6029,8 @@ final class CParser(AST) : Parser!AST
  * enum id = floatvalue;
  */
  AST.Expression e = new AST.RealExp(scanloc, floatvalue, t);
+ if (hasMinus)
+ e = new AST.NegExp(scanloc, e);
  auto v = new AST.VarDeclaration(scanloc, t, id, new AST.ExpInitializer(scanloc, e), STC.manifest);
  addSym(v);
  ++p;

compiler/test/compilable/imports/defines.c

@@ -55,3 +55,11 @@ int pr16199c()
 {
  return 8;
 }
+
+// https://issues.dlang.org/show_bug.cgi?id=24639
+#define NEGATIVE_I32 -1
+#define NEGATIVE_U32 -2U
+#define NEGATIVE_I64 -3LL
+#define NEGATIVE_U64 -4LLU
+#define NEGATIVE_F32 -5.0f
+#define NEGATIVE_F64 -6.0

compiler/test/compilable/testdefines.d

@@ -25,3 +25,17 @@ static assert(pr16199_ice == 3);
 
 static assert(pr16199d() == 7);
 static assert(pr16199c() == 8);
+
+// https://issues.dlang.org/show_bug.cgi?id=24639
+static assert(NEGATIVE_I32 == -1);
+static assert(NEGATIVE_U32 == cast(uint)-2);
+static assert(NEGATIVE_I64 == -3);
+static assert(NEGATIVE_U64 == cast(ulong)-4L);
+static assert(NEGATIVE_F32 == -5f);
+static assert(NEGATIVE_F64 == -6);
+static assert(is(typeof(NEGATIVE_I32) == int));
+static assert(is(typeof(NEGATIVE_U32) == uint));
+static assert(is(typeof(NEGATIVE_I64) == long));
+static assert(is(typeof(NEGATIVE_U64) == ulong));
+static assert(is(typeof(NEGATIVE_F32) == float));
+static assert(is(typeof(NEGATIVE_F64) == double));