add test case for fix to #7997

tests/template/tdefined_overload.nim

@@ -0,0 +1,46 @@
+discard """
+  output: "Valid and not defined"
+"""
+# test for issue #7997
+# checking for `when not defined` in a template for some compile time symbol
+# results in a compilation error of:
+# Error: obsolete usage of 'defined', use 'declared' instead
+# if the symbol is 'overloaded' by some variable or procedure, because in
+# that case the argument of `defined` is of kind `nkSym` instead of `nkIdent`
+# (for which was checked in `semexprs.semDefined`).
+
+block:
+  # check whether a proc with the same name as the argument to `defined`
+  # compiles
+  proc overloaded() =
+    discard
+
+  template definedCheck(): untyped =
+    when not defined(overloaded): true
+    else: false
+  doAssert definedCheck == true
+
+block:
+  # check whether a variable with the same name as the argument to `defined`
+  # compiles
+  var overloaded: int
+
+  template definedCheck(): untyped =
+    when not defined(overloaded): true
+    else: false
+  doAssert definedCheck == true
+
+block:
+  # check whether a non overloaded when check still works properly
+  when not defined(validIdentifier):
+    echo "Valid and not defined"
+
+block:
+  # now check that invalid identifiers cause a compilation error
+  # by using reject template.
+  template reject(b) =
+    static: doAssert(not compiles(b))
+
+  reject:
+    when defined(123):
+      echo "Invalid identifier! Will not be echoed"