fixes #24604; importc fails to generate stub type

changelog.md

@@ -19,6 +19,8 @@ errors.
 
 - With `-d:nimPreviewAsmSemSymbol`, backticked symbols are type checked in the `asm/emit` statements.
 
+- `importc` no longer implies `nodecl` for imported types. Use `header` or `nodecl` pragmas so that it doesn't generate a declaration for the type symbol.
+
 ## Standard library additions and changes
 
 [//]: # "Additions:"

compiler/ccgtypes.nim

@@ -234,6 +234,9 @@ proc mapReturnType(conf: ConfigRef; typ: PType): TCTypeKind =
 proc isImportedType(t: PType): bool =
   result = t.sym != nil and sfImportc in t.sym.flags
 
+proc isNoDeclType(t: PType): bool =
+  result = t.sym != nil and {lfNoDecl, lfHeader} * t.sym.loc.flags != {}
+
 proc isImportedCppType(t: PType): bool =
   let x = t.skipTypes(irrelevantForBackend)
   result = (t.sym != nil and sfInfixCall in t.sym.flags) or
@@ -390,7 +393,7 @@ proc getTypeForward(m: BModule; typ: PType; sig: SigHash): Rope =
   of tySequence, tyTuple, tyObject:
     result = getTypeName(m, typ, sig)
     m.forwTypeCache[sig] = result
-    if not isImportedType(concrete):
+    if not isNoDeclType(concrete):
       addForwardStructFormat(m, structOrUnion(typ), result)
     else:
       pushType(m, concrete)
@@ -1043,14 +1046,14 @@ proc getTypeDescAux(m: BModule; origTyp: PType, check: var IntSet; kind: TypeDes
       if result == "":
         result = getTypeName(m, origTyp, sig)
         m.forwTypeCache[sig] = result
-        if not isImportedType(t):
+        if not isNoDeclType(t):
           addForwardStructFormat(m, structOrUnion(t), result)
         assert m.forwTypeCache[sig] == result
       m.typeCache[sig] = result # always call for sideeffects:
       if not incompleteType(t):
         let recdesc = if t.kind != tyTuple: getRecordDesc(m, t, result, check)
                       else: getTupleDesc(m, t, result, check)
-        if not isImportedType(t):
+        if not isImportedType(t) and not isNoDeclType(t):
           m.s[cfsTypes].add(recdesc)
         elif tfIncompleteStruct notin t.flags:
           discard # addAbiCheck(m, t, result) # already handled elsewhere

lib/std/sysrand.nim

@@ -238,7 +238,7 @@ elif defined(ios) or defined(macosx):
   const errSecSuccess = 0 ## No error.
 
   type
-    SecRandom {.importc: "struct __SecRandom".} = object
+    SecRandom {.importc: "struct __SecRandom", header: "<Security/SecRandom.h>".} = object
 
     SecRandomRef = ptr SecRandom
       ## An abstract Core Foundation-type object containing information about a random number generator.

lib/system/dyncalls.nim

@@ -113,13 +113,13 @@ elif defined(windows) or defined(dos):
   #
   when defined(cpp):
     type
-      THINSTANCE {.importc: "HINSTANCE".} = object
+      THINSTANCE {.importc: "HINSTANCE", nodecl.} = object
         x: pointer
     proc getProcAddress(lib: THINSTANCE, name: cstring): ProcAddr {.
         importcpp: "(void*)GetProcAddress(@)", header: "<windows.h>", stdcall.}
   else:
     type
-      THINSTANCE {.importc: "HINSTANCE".} = pointer
+      THINSTANCE {.importc: "HINSTANCE", nodecl.} = pointer
     proc getProcAddress(lib: THINSTANCE, name: cstring): ProcAddr {.
         importc: "GetProcAddress", header: "<windows.h>", stdcall.}
 

tests/arc/t14472.nim

@@ -30,11 +30,11 @@ var s = bork()
 import tables
 
 type
-  cdbl {.importc: "double".} = object
+  cdbl {.importc: "double", nodecl.} = object
 
   MyObject = ref object of RootObj
     y: Table[string, cdbl]
-        
+
 
 proc test =
   var x = new(MyObject)

tests/ccgbugs/tcgbug.nim

@@ -140,7 +140,7 @@ block: # bug #9940
 typedef struct { int base; } S;
 """.}
 
-  type S {.importc: "S", completeStruct.} = object
+  type S {.importc: "S", nodecl, completeStruct.} = object
     base: cint
   proc init(x:ptr S) =
     x.base = 1

tests/ccgbugs/tctypes.nim

@@ -1,6 +1,6 @@
 discard """
   targets: "c cpp"
-  matrix: "--gc:refc; --gc:arc"
+  matrix: "--mm:refc; --mm:arc"
 """
 
 # bug #7308
@@ -41,3 +41,8 @@ block: # bug #11797
     proc foo3(): int32 = 2
     foo(proc(): cint = foo1())
     foo(proc(): int32 = foo3())
+
+
+block: # bug #24604
+  type MyType {.importc, incompleteStruct.} = object
+  var v {.exportc.}: ptr MyType

tests/cpp/tget_subsystem.nim

@@ -15,7 +15,7 @@ struct SystemManager {
 
 """.}
 
-type Input {.importcpp: "System::Input".} = object
+type Input {.importcpp: "System::Input", nodecl.} = object
 proc getSubsystem*[T](): ptr T {.
   importcpp: "SystemManager::getSubsystem<'*0>()", nodecl.}
 

tests/misc/msizeof5.nim

@@ -26,7 +26,7 @@ template ensureCgen(T: typedesc) =
   var a {.volatile.}: T
 
 block:
-  type Foo1Alias{.importc: "struct Foo1", size: sizeof(cint).} = object
+  type Foo1Alias{.importc: "struct Foo1", nodecl, size: sizeof(cint).} = object
     a: cint
   ensureCgen Foo1Alias
 

tests/misc/tsizeof.nim

@@ -488,7 +488,7 @@ typedef struct{
 """.}
 
 type
-  Foo {.importc.} = object
+  Foo {.importc, nodecl.} = object
 
   Bar = object
     b: byte
@@ -549,7 +549,7 @@ doAssert alignof(MyCustomAlignObject) == 32
 ##########################################
 
 type
-  imported_double {.importc: "double".} = object
+  imported_double {.importc: "double", nodecl.} = object
 
   Pod = object
     v* : imported_double

tests/niminaction/Chapter8/sfml/sfml.nim

@@ -1,11 +1,11 @@
 {.passL: "-lsfml-graphics -lsfml-system -lsfml-window".}
 
 type
-  VideoMode* {.importcpp: "sf::VideoMode".} = object
-  RenderWindowObj {.importcpp: "sf::RenderWindow".} = object
+  VideoMode* {.importcpp: "sf::VideoMode", nodecl.} = object
+  RenderWindowObj {.importcpp: "sf::RenderWindow", nodecl.} = object
   RenderWindow* = ptr RenderWindowObj
-  Color* {.importcpp: "sf::Color".} = object
-  Event* {.importcpp: "sf::Event".} = object
+  Color* {.importcpp: "sf::Color", nodecl.} = object
+  Event* {.importcpp: "sf::Event", nodecl.} = object
 
 {.push cdecl, header: "<SFML/Graphics.hpp>".}
 

tests/overload/tstatic_with_converter.nim

@@ -15,7 +15,7 @@ cimported set1_imported(double x) {
 
 """}
 
-type vfloat{.importc: "cimported".} = object
+type vfloat{.importc: "cimported", nodecl.} = object
 
 proc set1(a: float): vfloat {.importc: "set1_imported".}