fixes #1940; code breakage! stricter template evaluation

compiler/ast.nim

@@ -946,10 +946,7 @@ template `{}=`*(n: PNode, i: int, s: PNode): stmt =
   n.sons[i -| n] = s
 
 when defined(useNodeIds):
-  const nodeIdToDebug* = -1 # 884953 # 612794
-  #612840 # 612905 # 614635 # 614637 # 614641
-  # 423408
-  #429107 # 430443 # 441048 # 441090 # 441153
+  const nodeIdToDebug* = -1 # 299750 # 300761 #300863 # 300879
   var gNodeId: int
 
 proc newNode*(kind: TNodeKind): PNode =

compiler/sigmatch.nim

@@ -1232,7 +1232,7 @@ proc paramTypesMatchAux(m: var TCandidate, f, argType: PType,
     elif f.kind == tyStatic:
       return arg.typ.n
     else:
-      return argOrig
+      return argSemantized # argOrig
 
   if r != isNone and f.isInlineIterator:
     var inlined = newTypeS(tyStatic, c)

lib/pure/asyncdispatch.nim

@@ -1222,7 +1222,7 @@ proc processBody(node, retFutureSym: PNimrodNode,
   of nnkTryStmt:
     # try: await x; except: ...
     result = newNimNode(nnkStmtList, node)
-    template wrapInTry(n, tryBody: PNimrodNode) =
+    template wrapInTry(n, tryBody: expr) =
       var temp = n
       n[0] = tryBody
       tryBody = temp

tests/template/texponential_eval.nim

@@ -0,0 +1,47 @@
+# bug #1940
+
+discard """
+  nimout: '''===
+merge (A) with (B)
+merge (A B) with (C)
+merge (A B C) with (D)
+merge (A B C D) with (E)
+merge (A B C D E) with (F)
+==='''
+"""
+
+type SqlStmt = tuple
+  sql: string
+  parts: int
+
+proc sql(q: string): SqlStmt =
+  result.sql = q
+  result.parts = 1
+
+template `&%%`(x, y: SqlStmt): SqlStmt =
+  const a = x
+  const b = y
+
+  static:
+    #echo "some merge"
+    echo "merge (", a.sql, ") with (", b.sql, ")"
+
+
+  const newSql = a.sql & " " & b.sql
+  const newParts = a.parts + b.parts
+
+  SqlStmt((sql: newSql, parts: newParts))
+
+static:
+  echo "==="
+
+let c =(sql("A") &%%
+        sql("B")) &%%
+        sql("C")  &%%
+        sql("D") &%%
+        sql("E") &%%
+        sql("F")
+echo c.sql
+
+static:
+  echo "==="