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Implement language feature #6885 (#6954)

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cooldome 2017-12-25 00:22:03 +03:00 • committed by Andreas Rumpf
commit 2b3ec0a7c6
8 changed files with 131 additions and 14 deletions
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6
compiler/msgs.nim
View file

@ -26,7 +26,8 @@ type
errAtPopWithoutPush, errEmptyAsm, errInvalidIndentation,
errExceptionExpected, errExceptionAlreadyHandled,
errYieldNotAllowedHere, errYieldNotAllowedInTryStmt,
errInvalidNumberOfYieldExpr, errCannotReturnExpr, errAttemptToRedefine,
errInvalidNumberOfYieldExpr, errCannotReturnExpr,
errNoReturnWithReturnTypeNotAllowed, errAttemptToRedefine,
errStmtInvalidAfterReturn, errStmtExpected, errInvalidLabel,
errInvalidCmdLineOption, errCmdLineArgExpected, errCmdLineNoArgExpected,
errInvalidVarSubstitution, errUnknownVar, errUnknownCcompiler,
@ -179,8 +180,9 @@ const
errYieldNotAllowedInTryStmt: "'yield' cannot be used within 'try' in a non-inlined iterator",
errInvalidNumberOfYieldExpr: "invalid number of \'yield\' expressions",
errCannotReturnExpr: "current routine cannot return an expression",
errNoReturnWithReturnTypeNotAllowed: "routines with NoReturn pragma are not allowed to have return type",
errAttemptToRedefine: "redefinition of \'$1\'",
errStmtInvalidAfterReturn: "statement not allowed after \'return\', \'break\', \'raise\' or \'continue'",
errStmtInvalidAfterReturn: "statement not allowed after \'return\', \'break\', \'raise\', \'continue\' or proc call with noreturn pragma",
errStmtExpected: "statement expected",
errInvalidLabel: "\'$1\' is no label",
errInvalidCmdLineOption: "invalid command line option: \'$1\'",

2
compiler/pragmas.nim
View file

@ -771,6 +771,8 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: int,
of wNoreturn:
noVal(it)
incl(sym.flags, sfNoReturn)
if sym.ast[paramsPos][0].kind != nkEmpty:
localError(sym.ast[paramsPos][0].info, errNoReturnWithReturnTypeNotAllowed)
of wDynlib:
processDynLib(c, it, sym)
of wCompilerproc:

13
compiler/sem.nim
View file

@ -165,6 +165,19 @@ proc commonType*(x, y: PType): PType =
result = newType(k, r.owner)
result.addSonSkipIntLit(r)
proc endsInNoReturn(n: PNode): bool =
# check if expr ends in raise exception or call of noreturn proc
var it = n
while it.kind in {nkStmtList, nkStmtListExpr} and it.len > 0:
it = it.lastSon
result = it.kind == nkRaiseStmt or
it.kind in nkCallKinds and it[0].kind == nkSym and sfNoReturn in it[0].sym.flags
proc commonType*(x: PType, y: PNode): PType =
# ignore exception raising branches in case/if expressions
if endsInNoReturn(y): return x
commonType(x, y.typ)
proc newSymS(kind: TSymKind, n: PNode, c: PContext): PSym =
result = newSym(kind, considerQuotedIdent(n), getCurrOwner(c), n.info)
when defined(nimsuggest):

24
compiler/semstmts.nim
View file

@ -165,14 +165,14 @@ proc semIf(c: PContext, n: PNode): PNode =
it.sons[0] = forceBool(c, semExprWithType(c, it.sons[0]))
when not newScopeForIf: openScope(c)
it.sons[1] = semExprBranch(c, it.sons[1])
typ = commonType(typ, it.sons[1].typ)
typ = commonType(typ, it.sons[1])
closeScope(c)
elif it.len == 1:
hasElse = true
it.sons[0] = semExprBranchScope(c, it.sons[0])
typ = commonType(typ, it.sons[0].typ)
typ = commonType(typ, it.sons[0])
else: illFormedAst(it)
if isEmptyType(typ) or typ.kind == tyNil or not hasElse:
if isEmptyType(typ) or typ.kind in {tyNil, tyExpr} or not hasElse:
for it in n: discardCheck(c, it.lastSon)
result.kind = nkIfStmt
# propagate any enforced VoidContext:
@ -180,7 +180,8 @@ proc semIf(c: PContext, n: PNode): PNode =
else:
for it in n:
let j = it.len-1
it.sons[j] = fitNode(c, typ, it.sons[j], it.sons[j].info)
if not endsInNoReturn(it.sons[j]):
it.sons[j] = fitNode(c, typ, it.sons[j], it.sons[j].info)
result.kind = nkIfExpr
result.typ = typ
@ -213,7 +214,7 @@ proc semCase(c: PContext, n: PNode): PNode =
semCaseBranch(c, n, x, i, covered)
var last = sonsLen(x)-1
x.sons[last] = semExprBranchScope(c, x.sons[last])
typ = commonType(typ, x.sons[last].typ)
typ = commonType(typ, x.sons[last])
of nkElifBranch:
chckCovered = false
checkSonsLen(x, 2)
@ -221,13 +222,13 @@ proc semCase(c: PContext, n: PNode): PNode =
x.sons[0] = forceBool(c, semExprWithType(c, x.sons[0]))
when not newScopeForIf: openScope(c)
x.sons[1] = semExprBranch(c, x.sons[1])
typ = commonType(typ, x.sons[1].typ)
typ = commonType(typ, x.sons[1])
closeScope(c)
of nkElse:
chckCovered = false
checkSonsLen(x, 1)
x.sons[0] = semExprBranchScope(c, x.sons[0])
typ = commonType(typ, x.sons[0].typ)
typ = commonType(typ, x.sons[0])
hasElse = true
else:
illFormedAst(x)
@ -237,7 +238,7 @@ proc semCase(c: PContext, n: PNode): PNode =
else:
localError(n.info, errNotAllCasesCovered)
closeScope(c)
if isEmptyType(typ) or typ.kind == tyNil or not hasElse:
if isEmptyType(typ) or typ.kind in {tyNil, tyExpr} or not hasElse:
for i in 1..n.len-1: discardCheck(c, n.sons[i].lastSon)
# propagate any enforced VoidContext:
if typ == enforceVoidContext:
@ -246,7 +247,8 @@ proc semCase(c: PContext, n: PNode): PNode =
for i in 1..n.len-1:
var it = n.sons[i]
let j = it.len-1
it.sons[j] = fitNode(c, typ, it.sons[j], it.sons[j].info)
if not endsInNoReturn(it.sons[j]):
it.sons[j] = fitNode(c, typ, it.sons[j], it.sons[j].info)
result.typ = typ
proc semTry(c: PContext, n: PNode): PNode =
@ -1851,8 +1853,8 @@ proc semStmtList(c: PContext, n: PNode, flags: TExprFlags): PNode =
else:
n.typ = n.sons[i].typ
if not isEmptyType(n.typ): n.kind = nkStmtListExpr
case n.sons[i].kind
of LastBlockStmts:
if n.sons[i].kind in LastBlockStmts or
n.sons[i].kind in nkCallKinds and n.sons[i][0].kind == nkSym and sfNoReturn in n.sons[i][0].sym.flags:
for j in countup(i + 1, length - 1):
case n.sons[j].kind
of nkPragma, nkCommentStmt, nkNilLit, nkEmpty, nkBlockExpr,