+ added nimsuggest support for exception inlay hints (nim-lang#23202)

This adds nimsuggest support for displaying inlay hints for exceptions.
An inlay hint is displayed around function calls, that can raise an
exception, which isn't handled in the current subroutine (in other
words, exceptions that can propagate back to the caller). On mouse hover
on top of the hint, a list of exceptions that could propagate is shown.

The changes, required to support this are already commited to
nimlangserver and the VS code extension. The extension and the server
allow configuration for whether these new exception hints are enabled
(they can be enabled or disabled independently from the type hints), as
well as the inlay strings that are inserted before and after the name of
the function, around the function call. Potentially, one of these
strings can be empty, for example, the user can choose to add an inlay
hint only before the name of the function, or only after the name of the
function.

compiler/modulegraphs.nim

@@ -11,9 +11,9 @@
 ## represents a complete Nim project. Single modules can either be kept in RAM
 ## or stored in a rod-file.
 
-import std/[intsets, tables, hashes, strtabs]
+import std/[intsets, tables, hashes, strtabs, algorithm]
 import ../dist/checksums/src/checksums/md5
-import ast, astalgo, options, lineinfos,idents, btrees, ropes, msgs, pathutils, packages
+import ast, astalgo, options, lineinfos,idents, btrees, ropes, msgs, pathutils, packages, suggestsymdb
 import ic / [packed_ast, ic]
 
 
@@ -55,11 +55,6 @@ type
     concreteTypes*: seq[FullId]
     inst*: PInstantiation
 
-  SymInfoPair* = object
-    sym*: PSym
-    info*: TLineInfo
-    isDecl*: bool
-
   PipelinePass* = enum
     NonePass
     SemPass
@@ -108,7 +103,7 @@ type
     doStopCompile*: proc(): bool {.closure.}
     usageSym*: PSym # for nimsuggest
     owners*: seq[PSym]
-    suggestSymbols*: Table[FileIndex, seq[SymInfoPair]]
+    suggestSymbols*: SuggestSymbolDatabase
     suggestErrors*: Table[FileIndex, seq[Suggest]]
     methods*: seq[tuple[methods: seq[PSym], dispatcher: PSym]] # needs serialization!
     bucketTable*: CountTable[ItemId]
@@ -506,7 +501,7 @@ proc initModuleGraphFields(result: ModuleGraph) =
   result.importStack = @[]
   result.inclToMod = initTable[FileIndex, FileIndex]()
   result.owners = @[]
-  result.suggestSymbols = initTable[FileIndex, seq[SymInfoPair]]()
+  result.suggestSymbols = initTable[FileIndex, SuggestFileSymbolDatabase]()
   result.suggestErrors = initTable[FileIndex, seq[Suggest]]()
   result.methods = @[]
   result.compilerprocs = initStrTable()
@@ -712,16 +707,14 @@ func belongsToStdlib*(graph: ModuleGraph, sym: PSym): bool =
   ## Check if symbol belongs to the 'stdlib' package.
   sym.getPackageSymbol.getPackageId == graph.systemModule.getPackageId
 
-proc `==`*(a, b: SymInfoPair): bool =
-  result = a.sym == b.sym and a.info.exactEquals(b.info)
-
-proc fileSymbols*(graph: ModuleGraph, fileIdx: FileIndex): seq[SymInfoPair] =
-  result = graph.suggestSymbols.getOrDefault(fileIdx, @[])
+proc fileSymbols*(graph: ModuleGraph, fileIdx: FileIndex): SuggestFileSymbolDatabase =
+  result = graph.suggestSymbols.getOrDefault(fileIdx, newSuggestFileSymbolDatabase(fileIdx, optIdeExceptionInlayHints in graph.config.globalOptions))
+  doAssert(result.fileIndex == fileIdx)
 
 iterator suggestSymbolsIter*(g: ModuleGraph): SymInfoPair =
   for xs in g.suggestSymbols.values:
-    for x in xs:
-      yield x
+    for i in xs.lineInfo.low..xs.lineInfo.high:
+      yield xs.getSymInfoPair(i)
 
 iterator suggestErrorsIter*(g: ModuleGraph): Suggest =
   for xs in g.suggestErrors.values:

compiler/options.nim

@@ -86,6 +86,7 @@ type                          # please make sure we have under 32 options
                               # also: generate header file
     optIdeDebug               # idetools: debug mode
     optIdeTerse               # idetools: use terse descriptions
+    optIdeExceptionInlayHints
     optExcessiveStackTrace    # fully qualified module filenames
     optShowAllMismatches      # show all overloading resolution candidates
     optWholeProject           # for 'doc': output any dependency
@@ -298,6 +299,7 @@ type
   SuggestInlayHintKind* = enum
     sihkType = "Type",
     sihkParameter = "Parameter"
+    sihkException = "Exception"
 
   SuggestInlayHint* = ref object
     kind*: SuggestInlayHintKind

compiler/sempass2.nim

@@ -11,9 +11,9 @@ import
   ast, astalgo, msgs, renderer, magicsys, types, idents, trees,
   wordrecg, options, guards, lineinfos, semfold, semdata,
   modulegraphs, varpartitions, typeallowed, nilcheck, errorhandling,
-  semstrictfuncs
+  semstrictfuncs, suggestsymdb
 
-import std/[tables, intsets, strutils]
+import std/[tables, intsets, strutils, sequtils]
 
 when defined(nimPreviewSlimSystem):
   import std/assertions
@@ -66,8 +66,12 @@ discard """
 """
 
 type
+  CaughtExceptionsStack = object
+    nodes: seq[seq[PType]]
   TEffects = object
     exc: PNode  # stack of exceptions
+    when defined(nimsuggest):
+      caughtExceptions: CaughtExceptionsStack
     tags: PNode # list of tags
     forbids: PNode # list of tags
     bottom, inTryStmt, inExceptOrFinallyStmt, leftPartOfAsgn, inIfStmt, currentBlock: int
@@ -411,7 +415,7 @@ proc throws(tracked, n, orig: PNode) =
     else:
       tracked.add n
 
-proc getEbase(g: ModuleGraph; info: TLineInfo): PType =
+proc getEbase*(g: ModuleGraph; info: TLineInfo): PType =
   result = g.sysTypeFromName(info, "Exception")
 
 proc excType(g: ModuleGraph; n: PNode): PType =
@@ -492,6 +496,18 @@ proc catchesAll(tracked: PEffects) =
   if tracked.exc.len > 0:
     setLen(tracked.exc.sons, tracked.bottom)
 
+proc push(s: var CaughtExceptionsStack) =
+  s.nodes.add(@[])
+
+proc pop(s: var CaughtExceptionsStack) =
+  s.nodes.del(high(s.nodes))
+
+proc addCatch(s: var CaughtExceptionsStack, e: PType) =
+  s.nodes[high(s.nodes)].add(e)
+
+proc addCatchAll(s: var CaughtExceptionsStack) =
+  s.nodes[high(s.nodes)].add(nil)
+
 proc track(tracked: PEffects, n: PNode)
 proc trackTryStmt(tracked: PEffects, n: PNode) =
   let oldBottom = tracked.bottom
@@ -500,12 +516,33 @@ proc trackTryStmt(tracked: PEffects, n: PNode) =
   let oldState = tracked.init.len
   var inter: TIntersection = @[]
 
+  when defined(nimsuggest):
+    tracked.caughtExceptions.push
+    for i in 1..<n.len:
+      let b = n[i]
+      if b.kind == nkExceptBranch:
+        if b.len == 1:
+          tracked.caughtExceptions.addCatchAll
+        else:
+          for j in 0..<b.len - 1:
+            if b[j].isInfixAs():
+              assert(b[j][1].kind == nkType)
+              tracked.caughtExceptions.addCatch(b[j][1].typ)
+            else:
+              assert(b[j].kind == nkType)
+              tracked.caughtExceptions.addCatch(b[j].typ)
+      else:
+        assert b.kind == nkFinally
+
   inc tracked.inTryStmt
   track(tracked, n[0])
   dec tracked.inTryStmt
   for i in oldState..<tracked.init.len:
     addToIntersection(inter, tracked.init[i], bsNone)
 
+  when defined(nimsuggest):
+    tracked.caughtExceptions.pop
+
   var branches = 1
   var hasFinally = false
   inc tracked.inExceptOrFinallyStmt
@@ -917,6 +954,19 @@ proc checkForSink(tracked: PEffects; n: PNode) =
   if tracked.inIfStmt == 0 and optSinkInference in tracked.config.options:
     checkForSink(tracked.config, tracked.c.idgen, tracked.owner, n)
 
+proc markCaughtExceptions(tracked: PEffects; g: ModuleGraph; info: TLineInfo; s: PSym; usageSym: var PSym) =
+  when defined(nimsuggest):
+    proc internalMarkCaughtExceptions(tracked: PEffects; q: var SuggestFileSymbolDatabase; info: TLineInfo) =
+      var si = q.findSymInfoIndex(info)
+      if si != -1:
+        q.caughtExceptionsSet[si] = true
+        for w1 in tracked.caughtExceptions.nodes:
+          for w2 in w1:
+            q.caughtExceptions[si].add(w2)
+
+    if optIdeExceptionInlayHints in tracked.config.globalOptions:
+      internalMarkCaughtExceptions(tracked, g.suggestSymbols.mgetOrPut(info.fileIndex, newSuggestFileSymbolDatabase(info.fileIndex, true)), info)
+
 proc trackCall(tracked: PEffects; n: PNode) =
   template gcsafeAndSideeffectCheck() =
     if notGcSafe(op) and not importedFromC(a):
@@ -937,6 +987,13 @@ proc trackCall(tracked: PEffects; n: PNode) =
     if tracked.owner.kind != skMacro and n.typ.skipTypes(abstractVar).kind != tyOpenArray:
       createTypeBoundOps(tracked, n.typ, n.info)
 
+  when defined(nimsuggest):
+    var actualLoc = a.info
+    if n.kind == nkHiddenCallConv:
+      actualLoc = n.info
+    if a.kind == nkSym:
+      markCaughtExceptions(tracked, tracked.graph, actualLoc, a.sym, tracked.graph.usageSym)
+
   let notConstExpr = getConstExpr(tracked.ownerModule, n, tracked.c.idgen, tracked.graph) == nil
   if notConstExpr:
     if a.kind == nkCast and a[1].typ.kind == tyProc:

compiler/suggest.nim

@@ -32,7 +32,7 @@
 
 # included from sigmatch.nim
 
-import prefixmatches
+import prefixmatches, suggestsymdb
 from wordrecg import wDeprecated, wError, wAddr, wYield
 
 import std/[algorithm, sets, parseutils, tables]
@@ -114,6 +114,10 @@ proc getTokenLenFromSource(conf: ConfigRef; ident: string; info: TLineInfo; skip
     result = skipUntil(line, '`', column)
     if cmpIgnoreStyle(line[column..column + result - 1], ident) != 0:
       result = 0
+  elif column >= 0 and line[column] == '`' and isOpeningBacktick(column):
+    result = skipUntil(line, '`', column + 1) + 2
+    if cmpIgnoreStyle(line[column + 1..column + result - 2], ident) != 0:
+      result = 0
   elif ident[0] in linter.Letters and ident[^1] != '=':
     result = identLen(line, column)
     if cmpIgnoreStyle(line[column..column + result - 1], ident[0..min(result-1,len(ident)-1)]) != 0:
@@ -265,7 +269,7 @@ proc `$`*(suggest: Suggest): string =
       result.add(sep)
       result.add($suggest.endCol)
 
-proc suggestToSuggestInlayHint*(sug: Suggest): SuggestInlayHint =
+proc suggestToSuggestInlayTypeHint*(sug: Suggest): SuggestInlayHint =
   SuggestInlayHint(
     kind: sihkType,
     line: sug.line,
@@ -277,6 +281,30 @@ proc suggestToSuggestInlayHint*(sug: Suggest): SuggestInlayHint =
     tooltip: ""
   )
 
+proc suggestToSuggestInlayExceptionHintLeft*(sug: Suggest, propagatedExceptions: seq[PType]): SuggestInlayHint =
+  SuggestInlayHint(
+    kind: sihkException,
+    line: sug.line,
+    column: sug.column,
+    label: "try ",
+    paddingLeft: false,
+    paddingRight: false,
+    allowInsert: false,
+    tooltip: "propagated exceptions: " & $propagatedExceptions
+  )
+
+proc suggestToSuggestInlayExceptionHintRight*(sug: Suggest, propagatedExceptions: seq[PType]): SuggestInlayHint =
+  SuggestInlayHint(
+    kind: sihkException,
+    line: sug.line,
+    column: sug.column + sug.tokenLen,
+    label: "!",
+    paddingLeft: false,
+    paddingRight: false,
+    allowInsert: false,
+    tooltip: "propagated exceptions: " & $propagatedExceptions
+  )
+
 proc suggestResult*(conf: ConfigRef; s: Suggest) =
   if not isNil(conf.suggestionResultHook):
     conf.suggestionResultHook(s)
@@ -534,6 +562,16 @@ proc isTracked*(current, trackPos: TLineInfo, tokenLen: int): bool =
   else:
     result = false
 
+proc isTracked*(current, trackPos: TinyLineInfo, tokenLen: int): bool =
+  if current.line==trackPos.line:
+    let col = trackPos.col
+    if col >= current.col and col <= current.col+tokenLen-1:
+      result = true
+    else:
+      result = false
+  else:
+    result = false
+
 when defined(nimsuggest):
   # Since TLineInfo defined a == operator that doesn't include the column,
   # we map TLineInfo to a unique int here for this lookup table:
@@ -584,7 +622,7 @@ proc suggestSym*(g: ModuleGraph; info: TLineInfo; s: PSym; usageSym: var PSym; i
   ## misnamed: should be 'symDeclared'
   let conf = g.config
   when defined(nimsuggest):
-    g.suggestSymbols.mgetOrPut(info.fileIndex, @[]).add SymInfoPair(sym: s, info: info, isDecl: isDecl)
+    g.suggestSymbols.add SymInfoPair(sym: s, info: info, isDecl: isDecl), optIdeExceptionInlayHints in g.config.globalOptions
 
     if conf.suggestVersion == 0:
       if s.allUsages.len == 0: