4 files changed, 20 insertions, 25 deletions
diff --git a/lib/core/macros.nim b/lib/core/macros.nim
index 4d76d60c2..aec766068 100644
--- a/lib/core/macros.nim
+++ b/lib/core/macros.nim
@@ -240,7 +240,7 @@ else: # bootstrapping substitute
 when defined(nimHasSymOwnerInMacro):
   proc owner*(sym: NimNode): NimNode {.magic: "SymOwner", noSideEffect.}
     ## accepts node of kind nnkSym and returns its owner's symbol.
-    ## result is also mnde of kind nnkSym if owner exists otherwise 
+    ## result is also mnde of kind nnkSym if owner exists otherwise
     ## nnkNilLit is returned
 
 proc getType*(n: NimNode): NimNode {.magic: "NGetType", noSideEffect.}
@@ -977,7 +977,7 @@ proc newIfStmt*(branches: varargs[tuple[cond, body: NimNode]]):
   ##
   result = newNimNode(nnkIfStmt)
   for i in branches:
-    result.add(newNimNode(nnkElifBranch).add(i.cond, i.body))
+    result.add(newTree(nnkElifBranch, i.cond, i.body))
 
 proc newEnum*(name: NimNode, fields: openArray[NimNode],
               public, pure: bool): NimNode {.compileTime.} =
diff --git a/lib/system.nim b/lib/system.nim
index 8654f12a1..ef6138ad1 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -1552,7 +1552,7 @@ proc delete*[T](x: var seq[T], i: Natural) {.noSideEffect.} =
     defaultImpl()
   else:
     when defined(js):
-      {.emit: "`x`[`x`_Idx].splice(`i`, 1);".}
+      {.emit: "`x`.splice(`i`, 1);".}
     else:
       defaultImpl()
 
@@ -1574,7 +1574,7 @@ proc insert*[T](x: var seq[T], item: T, i = 0.Natural) {.noSideEffect.} =
   else:
     when defined(js):
       var it : T
-      {.emit: "`x`[`x`_Idx].splice(`i`, 0, `it`);".}
+      {.emit: "`x`.splice(`i`, 0, `it`);".}
     else:
       defaultImpl()
   x[i] = item
@@ -2741,12 +2741,12 @@ type
 when defined(JS):
   proc add*(x: var string, y: cstring) {.asmNoStackFrame.} =
     asm """
-      var len = `x`.length-1;
+      if (`x` === null) { `x` = []; }
+      var off = `x`.length;
+      `x`.length += `y`.length;
       for (var i = 0; i < `y`.length; ++i) {
-        `x`[len] = `y`.charCodeAt(i);
-        ++len;
+        `x`[off+i] = `y`.charCodeAt(i);
       }
-      `x`[len] = 0
     """
   proc add*(x: var cstring, y: cstring) {.magic: "AppendStrStr".}
 
@@ -3784,8 +3784,11 @@ template assertImpl(cond: bool, msg = "", enabled: static[bool]) =
   bind instantiationInfo
   mixin failedAssertImpl
   when enabled:
-    if not cond:
-      failedAssertImpl(loc & " `" & astToStr(cond) & "` " & msg)
+    # for stacktrace; fixes #8928 ; Note: `fullPaths = true` is correct
+    # here, regardless of --excessiveStackTrace
+    {.line: instantiationInfo(fullPaths = true).}:
+      if not cond:
+        failedAssertImpl(loc & " `" & astToStr(cond) & "` " & msg)
 
 template assert*(cond: bool, msg = "") =
   ## Raises ``AssertionError`` with `msg` if `cond` is false. Note
diff --git a/lib/system/hti.nim b/lib/system/hti.nim
index bb3769ac4..9931fa11e 100644
--- a/lib/system/hti.nim
+++ b/lib/system/hti.nim
@@ -11,7 +11,7 @@ when declared(ThisIsSystem):
   # we are in system module:
   {.pragma: codegenType, compilerproc.}
 else:
-  {.pragma: codegenType, importc.}
+  {.pragma: codegenType.}
 
 type
   # This should be the same as ast.TTypeKind
diff --git a/lib/system/jssys.nim b/lib/system/jssys.nim
index 152b48c24..836ac198d 100644
--- a/lib/system/jssys.nim
+++ b/lib/system/jssys.nim
@@ -182,12 +182,10 @@ proc setConstr() {.varargs, asmNoStackFrame, compilerproc.} =
 proc makeNimstrLit(c: cstring): string {.asmNoStackFrame, compilerproc.} =
   {.emit: """
   var ln = `c`.length;
-  var result = new Array(ln + 1);
-  var i = 0;
-  for (; i < ln; ++i) {
+  var result = new Array(ln);
+  for (var i = 0; i < ln; ++i) {
     result[i] = `c`.charCodeAt(i);
   }
-  result[i] = 0; // terminating zero
   return result;
   """.}
 
@@ -225,13 +223,12 @@ proc cstrToNimstr(c: cstring): string {.asmNoStackFrame, compilerproc.} =
     }
     ++r;
   }
-  result[r] = 0; // terminating zero
   return result;
   """.}
 
 proc toJSStr(s: string): cstring {.asmNoStackFrame, compilerproc.} =
   asm """
-  var len = `s`.length-1;
+  var len = `s`.length;
   var asciiPart = new Array(len);
   var fcc = String.fromCharCode;
   var nonAsciiPart = null;
@@ -262,10 +259,7 @@ proc toJSStr(s: string): cstring {.asmNoStackFrame, compilerproc.} =
 
 proc mnewString(len: int): string {.asmNoStackFrame, compilerproc.} =
   asm """
-    var result = new Array(`len`+1);
-    result[0] = 0;
-    result[`len`] = 0;
-    return result;
+    return new Array(`len`);
   """
 
 proc SetCard(a: int): int {.compilerproc, asmNoStackFrame.} =
@@ -323,7 +317,7 @@ proc cmpStrings(a, b: string): int {.asmNoStackFrame, compilerProc.} =
     if (`a` == `b`) return 0;
     if (!`a`) return -1;
     if (!`b`) return 1;
-    for (var i = 0; i < `a`.length - 1 && i < `b`.length - 1; i++) {
+    for (var i = 0; i < `a`.length && i < `b`.length; i++) {
       var result = `a`[i] - `b`[i];
       if (result != 0) return result;
     }
@@ -651,9 +645,7 @@ proc isObj(obj, subclass: PNimType): bool {.compilerproc.} =
   return true
 
 proc addChar(x: string, c: char) {.compilerproc, asmNoStackFrame.} =
-  asm """
-    `x`[`x`.length-1] = `c`; `x`.push(0);
-  """
+  asm "`x`.push(`c`);"
 
 {.pop.}