diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/semtypes.nim | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/compiler/semtypes.nim b/compiler/semtypes.nim index cb3d24a76..e86b527d6 100644 --- a/compiler/semtypes.nim +++ b/compiler/semtypes.nim @@ -1145,14 +1145,29 @@ proc semGeneric(c: PContext, n: PNode, s: PSym, prev: PType): PType = if tx != result and tx.kind == tyObject and tx.sons[0] != nil: semObjectTypeForInheritedGenericInst(c, n, tx) +proc maybeAliasType(c: PContext; typeExpr, prev: PType): PType + proc semTypeExpr(c: PContext, n: PNode; prev: PType): PType = var n = semExprWithType(c, n, {efDetermineType}) if n.typ.kind == tyTypeDesc: result = n.typ.base - # fix types constructed by macros: - if prev != nil and prev.sym != nil and result.sym.isNil: - result.sym = prev.sym - result.sym.typ = result + # fix types constructed by macros/template: + if prev != nil and prev.sym != nil: + if result.sym.isNil: + # Behold! you're witnessing enormous power yielded + # by macros. Only macros can summon unnamed types + # and cast spell upon AST. Here we need to give + # it a name taken from left hand side's node + result.sym = prev.sym + result.sym.typ = result + else: + # Less powerful routine like template do not have + # the ability to produce unnamed types. But still + # it has wild power to push a type a bit too far. + # So we need to hold it back using alias and prevent + # unnecessary new type creation + let alias = maybeAliasType(c, result, prev) + if alias != nil: result = alias else: localError(n.info, errTypeExpected, n.renderTree) result = errorType(c) |