# # # The Nim Compiler # (c) Copyright 2013 Andreas Rumpf # # See the file "copying.txt", included in this # distribution, for details about the copyright. # # This module implements the semantic checking pass. import ast, strutils, hashes, options, lexer, astalgo, trees, treetab, wordrecg, ropes, msgs, os, condsyms, idents, renderer, types, platform, math, magicsys, parser, nversion, nimsets, semfold, modulepaths, importer, procfind, lookups, rodread, pragmas, passes, semdata, semtypinst, sigmatch, intsets, transf, vmdef, vm, idgen, aliases, cgmeth, lambdalifting, evaltempl, patterns, parampatterns, sempass2, nimfix.pretty, semmacrosanity, semparallel, lowerings, pluginsupport, plugins.active from modulegraphs import ModuleGraph when defined(nimfix): import nimfix.prettybase # implementation proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode {.procvar.} proc semExprWithType(c: PContext, n: PNode, flags: TExprFlags = {}): PNode {. procvar.} proc semExprNoType(c: PContext, n: PNode): PNode proc semExprNoDeref(c: PContext, n: PNode, flags: TExprFlags = {}): PNode proc semProcBody(c: PContext, n: PNode): PNode proc fitNode(c: PContext, formal: PType, arg: PNode; info: TLineInfo): PNode proc changeType(n: PNode, newType: PType, check: bool) proc semLambda(c: PContext, n: PNode, flags: TExprFlags): PNode proc semTypeNode(c: PContext, n: PNode, prev: PType): PType proc semStmt(c: PContext, n: PNode): PNode proc semParamList(c: PContext, n, genericParams: PNode, s: PSym) proc addParams(c: PContext, n: PNode, kind: TSymKind) proc maybeAddResult(c: PContext, s: PSym, n: PNode) proc tryExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode proc activate(c: PContext, n: PNode) proc semQuoteAst(c: PContext, n: PNode): PNode proc finishMethod(c: PContext, s: PSym) proc evalAtCompileTime(c: PContext, n: PNode): PNode proc indexTypesMatch(c: PContext, f, a: PType, arg: PNode): PNode proc isArrayConstr(n: PNode): bool {.inline.} = result = n.kind == nkBracket and n.typ.skipTypes(abstractInst).kind == tyArray template semIdeForTemplateOrGenericCheck(n, requiresCheck) = # we check quickly if the node is where the cursor is when defined(nimsuggest): if n.info.fileIndex == gTrackPos.fileIndex and n.info.line == gTrackPos.line: requiresCheck = true template semIdeForTemplateOrGeneric(c: PContext; n: PNode; requiresCheck: bool) = # use only for idetools support; this is pretty slow so generics and # templates perform some quick check whether the cursor is actually in # the generic or template. when defined(nimsuggest): if gCmd == cmdIdeTools and requiresCheck: #if optIdeDebug in gGlobalOptions: # echo "passing to safeSemExpr: ", renderTree(n) discard safeSemExpr(c, n) proc fitNode(c: PContext, formal: PType, arg: PNode; info: TLineInfo): PNode = if arg.typ.isNil: localError(arg.info, errExprXHasNoType, renderTree(arg, {renderNoComments})) # error correction: result = copyTree(arg) result.typ = formal else: result = indexTypesMatch(c, formal, arg.typ, arg) if result == nil: typeMismatch(info, formal, arg.typ) # error correction: result = copyTree(arg) result.typ = formal else: let x = result.skipConv if x.kind == nkPar and formal.kind != tyExpr: changeType(x, formal, check=true) else: result = skipHiddenSubConv(result) #result.typ = takeType(formal, arg.typ) #echo arg.info, " picked ", result.typ.typeToString proc inferWithMetatype(c: PContext, formal: PType, arg: PNode, coerceDistincts = false): PNode var commonTypeBegin = PType(kind: tyExpr) proc commonType*(x, y: PType): PType = # new type relation that is used for array constructors, # if expressions, etc.: if x == nil: return x if y == nil: return y var a = skipTypes(x, {tyGenericInst, tyAlias, tySink}) var b = skipTypes(y, {tyGenericInst, tyAlias, tySink}) result = x if a.kind in {tyExpr, tyNil}: result = y elif b.kind in {tyExpr, tyNil}: result = x elif a.kind == tyStmt: result = a elif b.kind == tyStmt: result = b elif a.kind == tyTypeDesc: # turn any concrete typedesc into the abstract typedesc type if a.sons == nil: result = a else: result = newType(tyTypeDesc, a.owner) rawAddSon(result, newType(tyNone, a.owner)) elif b.kind in {tyArray, tySet, tySequence} and a.kind == b.kind: # check for seq[empty] vs. seq[int] let idx = ord(b.kind == tyArray) if a.sons[idx].kind == tyEmpty: return y elif a.kind == tyTuple and b.kind == tyTuple and a.len == b.len: var nt: PType for i in 0.. 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): suggestDecl(c, n, result) proc newSymG*(kind: TSymKind, n: PNode, c: PContext): PSym = proc `$`(kind: TSymKind): string = substr(system.`$`(kind), 2).toLowerAscii # like newSymS, but considers gensym'ed symbols if n.kind == nkSym: # and sfGenSym in n.sym.flags: result = n.sym if result.kind != kind: localError(n.info, "cannot use symbol of kind '" & $result.kind & "' as a '" & $kind & "'") if sfGenSym in result.flags and result.kind notin {skTemplate, skMacro, skParam}: # declarative context, so produce a fresh gensym: result = copySym(result) result.ast = n.sym.ast put(c.p, n.sym, result) # when there is a nested proc inside a template, semtmpl # will assign a wrong owner during the first pass over the # template; we must fix it here: see #909 result.owner = getCurrOwner(c) else: result = newSym(kind, considerQuotedIdent(n), getCurrOwner(c), n.info) #if kind in {skForVar, skLet, skVar} and result.owner.kind == skModule: # incl(result.flags, sfGlobal) when defined(nimsuggest): suggestDecl(c, n, result) proc semIdentVis(c: PContext, kind: TSymKind, n: PNode, allowed: TSymFlags): PSym # identifier with visibility proc semIdentWithPragma(c: PContext, kind: TSymKind, n: PNode, allowed: TSymFlags): PSym proc typeAllowedCheck(info: TLineInfo; typ: PType; kind: TSymKind) = let t = typeAllowed(typ, kind) if t != nil: if t == typ: localError(info, "invalid type: '" & typeToString(typ) & "'") else: localError(info, "invalid type: '" & typeToString(t) & "' in this context: '" & typeToString(typ) & "'") proc paramsTypeCheck(c: PContext, typ: PType) {.inline.} = typeAllowedCheck(typ.n.info, typ, skProc) proc expectMacroOrTemplateCall(c: PContext, n: PNode): PSym proc semDirectOp(c: PContext, n: PNode, flags: TExprFlags): PNode proc semWhen(c: PContext, n: PNode, semCheck: bool = true): PNode proc semTemplateExpr(c: PContext, n: PNode, s: PSym, flags: TExprFlags = {}): PNode proc semMacroExpr(c: PContext, n, nOrig: PNode, sym: PSym, flags: TExprFlags = {}): PNode proc symFromType(t: PType, info: TLineInfo): PSym = if t.sym != nil: return t.sym result = newSym(skType, getIdent"AnonType", t.owner, info) result.flags.incl sfAnon result.typ = t proc symNodeFromType(c: PContext, t: PType, info: TLineInfo): PNode = result = newSymNode(symFromType(t, info), info) result.typ = makeTypeDesc(c, t) when false: proc createEvalContext(c: PContext, mode: TEvalMode): PEvalContext = result = newEvalContext(c.module, mode) result.getType = proc (n: PNode): PNode = result = tryExpr(c, n) if result == nil: result = newSymNode(errorSym(c, n)) elif result.typ == nil: result = newSymNode(getSysSym"void") else: result.typ = makeTypeDesc(c, result.typ) result.handleIsOperator = proc (n: PNode): PNode = result = isOpImpl(c, n) proc hasCycle(n: PNode): bool = incl n.flags, nfNone for i in 0.. 100: globalError(s.info, errTemplateInstantiationTooNested) c.friendModules.add(s.owner.getModule) result = macroResult excl(result.flags, nfSem) #resetSemFlag n if s.typ.sons[0] == nil: result = semStmt(c, result) else: case s.typ.sons[0].kind of tyExpr: # BUGFIX: we cannot expect a type here, because module aliases would not # work then (see the ``tmodulealias`` test) # semExprWithType(c, result) result = semExpr(c, result, flags) of tyStmt: result = semStmt(c, result) of tyTypeDesc: if result.kind == nkStmtList: result.kind = nkStmtListType var typ = semTypeNode(c, result, nil) result.typ = makeTypeDesc(c, typ) #result = symNodeFromType(c, typ, n.info) else: var retType = s.typ.sons[0] if s.ast[genericParamsPos] != nil and retType.isMetaType: # The return type may depend on the Macro arguments # e.g. template foo(T: typedesc): seq[T] # We will instantiate the return type here, because # we now know the supplied arguments var paramTypes = newIdTable() for param, value in genericParamsInMacroCall(s, call): idTablePut(paramTypes, param.typ, value.typ) retType = generateTypeInstance(c, paramTypes, macroResult.info, retType) result = semExpr(c, result, flags) result = fitNode(c, retType, result, result.info) #GlobalError(s.info, errInvalidParamKindX, typeToString(s.typ.sons[0])) dec(evalTemplateCounter) discard c.friendModules.pop() proc semMacroExpr(c: PContext, n, nOrig: PNode, sym: PSym, flags: TExprFlags = {}): PNode = pushInfoContext(nOrig.info) markUsed(n.info, sym, c.graph.usageSym) styleCheckUse(n.info, sym) if sym == c.p.owner: globalError(n.info, errRecursiveDependencyX, sym.name.s) let genericParams = if sfImmediate in sym.flags: 0 else: sym.ast[genericParamsPos].len let suppliedParams = max(n.safeLen - 1, 0) if suppliedParams < genericParams: globalError(n.info, errMissingGenericParamsForTemplate, n.renderTree) #if c.evalContext == nil: # c.evalContext = c.createEvalContext(emStatic) result = evalMacroCall(c.module, c.cache, n, nOrig, sym) if efNoSemCheck notin flags: result = semAfterMacroCall(c, n, result, sym, flags) result = wrapInComesFrom(nOrig.info, sym, result) popInfoContext() proc forceBool(c: PContext, n: PNode): PNode = result = fitNode(c, getSysType(tyBool), n, n.info) if result == nil: result = n proc semConstBoolExpr(c: PContext, n: PNode): PNode = let nn = semExprWithType(c, n) result = fitNode(c, getSysType(tyBool), nn, nn.info) if result == nil: localError(n.info, errConstExprExpected) return nn result = getConstExpr(c.module, result) if result == nil: localError(n.info, errConstExprExpected) result = nn proc semGenericStmt(c: PContext, n: PNode): PNode proc semConceptBody(c: PContext, n: PNode): PNode include semtypes, semtempl, semgnrc, semstmts, semexprs proc addCodeForGenerics(c: PContext, n: PNode) = for i in countup(c.lastGenericIdx, c.generics.len - 1): var prc = c.generics[i].inst.sym if prc.kind in {skProc, skFunc, skMethod, skConverter} and prc.magic == mNone: if prc.ast == nil or prc.ast.sons[bodyPos] == nil: internalError(prc.info, "no code for " & prc.name.s) else: addSon(n, prc.ast) c.lastGenericIdx = c.generics.len proc myOpen(graph: ModuleGraph; module: PSym; cache: IdentCache): PPassContext = var c = newContext(graph, module, cache) if c.p != nil: internalError(module.info, "sem.myOpen") c.semConstExpr = semConstExpr c.semExpr = semExpr c.semTryExpr = tryExpr c.semTryConstExpr = tryConstExpr c.semOperand = semOperand c.semConstBoolExpr = semConstBoolExpr c.semOverloadedCall = semOverloadedCall c.semInferredLambda = semInferredLambda c.semGenerateInstance = generateInstance c.semTypeNode = semTypeNode c.instTypeBoundOp = sigmatch.instTypeBoundOp pushProcCon(c, module) pushOwner(c, c.module) c.importTable = openScope(c) c.importTable.addSym(module) # a module knows itself if sfSystemModule in module.flags: magicsys.systemModule = module # set global variable! c.topLevelScope = openScope(c) # don't be verbose unless the module belongs to the main package: if module.owner.id == gMainPackageId: gNotes = gMainPackageNotes else: if gMainPackageNotes == {}: gMainPackageNotes = gNotes gNotes = ForeignPackageNotes result = c proc myOpenCached(graph: ModuleGraph; module: PSym; rd: PRodReader): PPassContext = result = myOpen(graph, module, rd.cache) proc replayMethodDefs(graph: ModuleGraph; rd: PRodReader) = for m in items(rd.methods): methodDef(graph, m, true) proc isImportSystemStmt(n: PNode): bool = if magicsys.systemModule == nil: return false case n.kind of nkImportStmt: for x in n: if x.kind == nkIdent: let f = checkModuleName(x, false) if f == magicsys.systemModule.info.fileIndex: return true of nkImportExceptStmt, nkFromStmt: if n[0].kind == nkIdent: let f = checkModuleName(n[0], false) if f == magicsys.systemModule.info.fileIndex: return true else: discard proc semStmtAndGenerateGenerics(c: PContext, n: PNode): PNode = if n.kind == nkDefer: localError(n.info, "defer statement not supported at top level") if c.topStmts == 0 and not isImportSystemStmt(n): if sfSystemModule notin c.module.flags and n.kind notin {nkEmpty, nkCommentStmt}: c.importTable.addSym magicsys.systemModule # import the "System" identifier importAllSymbols(c, magicsys.systemModule) inc c.topStmts else: inc c.topStmts if sfNoForward in c.module.flags: result = semAllTypeSections(c, n) else: result = n result = semStmt(c, result) when false: # Code generators are lazy now and can deal with undeclared procs, so these # steps are not required anymore and actually harmful for the upcoming # destructor support. # BUGFIX: process newly generated generics here, not at the end! if c.lastGenericIdx < c.generics.len: var a = newNodeI(nkStmtList, n.info) addCodeForGenerics(c, a) if sonsLen(a) > 0: # a generic has been added to `a`: if result.kind != nkEmpty: addSon(a, result) result = a result = hloStmt(c, result) if gCmd == cmdInteractive and not isEmptyType(result.typ): result = buildEchoStmt(c, result) if gCmd == cmdIdeTools: appendToModule(c.module, result) result = transformStmt(c.module, result) proc recoverContext(c: PContext) = # clean up in case of a semantic error: We clean up the stacks, etc. This is # faster than wrapping every stack operation in a 'try finally' block and # requires far less code. c.currentScope = c.topLevelScope while getCurrOwner(c).kind != skModule: popOwner(c) while c.p != nil and c.p.owner.kind != skModule: c.p = c.p.next proc myProcess(context: PPassContext, n: PNode): PNode = var c = PContext(context) # no need for an expensive 'try' if we stop after the first error anyway: if msgs.gErrorMax <= 1: result = semStmtAndGenerateGenerics(c, n) else: let oldContextLen = msgs.getInfoContextLen() let oldInGenericInst = c.inGenericInst try: result = semStmtAndGenerateGenerics(c, n) except ERecoverableError, ESuggestDone: recoverContext(c) c.inGenericInst = oldInGenericInst msgs.setInfoContextLen(oldContextLen) if getCurrentException() of ESuggestDone: c.suggestionsMade = true result = nil else: result = ast.emptyNode #if gCmd == cmdIdeTools: findSuggest(c, n) proc testExamples(c: PContext) = let inp = toFullPath(c.module.info) let outp = inp.changeFileExt"" & "_examples.nim" renderModule(c.runnableExamples, inp, outp) let backend = if isDefined("js"): "js" elif isDefined("cpp"): "cpp" elif isDefined("objc"): "objc" else: "c" if os.execShellCmd("nim " & backend & " -r " & outp) != 0: quit "[Examples] failed" removeFile(outp) proc myClose(graph: ModuleGraph; context: PPassContext, n: PNode): PNode = var c = PContext(context) if gCmd == cmdIdeTools and not c.suggestionsMade: suggestSentinel(c) closeScope(c) # close module's scope rawCloseScope(c) # imported symbols; don't check for unused ones! result = newNode(nkStmtList) if n != nil: internalError(n.info, "n is not nil") #result := n; addCodeForGenerics(c, result) if c.module.ast != nil: result.add(c.module.ast) if c.rd != nil: replayMethodDefs(graph, c.rd) popOwner(c) popProcCon(c) if c.runnableExamples != nil: testExamples(c) const semPass* = makePass(myOpen, myOpenCached, myProcess, myClose)