Templates bad expansions in arguments

[juancarlospaco]

Description

Templates expand to rvalue=rvalue (right-hand side literal values) arguments when the template argument and the function argument have the same name.

Same happens inside a main() function.

Alternative can be change identifier names like body = bodi in arguments, but its weird and don't change the fact that the compiler is using literal values as identifier names in expansions.

func f(a: string) = discard       # Expands to:
template t(a: string) = f(a = a)  # f("BUG" = "BUG")
t(a = "BUG")                      # Should be:
                                  # f(a = "BUG")

Nim Version

2.2.1

Current Output

temp.nim(3, 7) Error: identifier expected, but found '"BUG"'

Expected Output

Compile Ok, or give some kind of ambiguous identifier error?

Known Workarounds

Change the name of the arguments, but you have to edit the whole code.

I found this because I have templates that use body=body for HTTP code, and the expandMacros shows code like f( "BUG" = "BUG" ), but should be like f( body = "BUG" ), then complains Error: identifier expected, but found '"BUG"'.

Additional Information

See Bisect below...

[juancarlospaco]

!nim c

func f(a: string) = discard
template t(a: string) = f(a = a)
t(a = "BUG")

[github-actions[bot]]

:penguin: Linux bisect by @juancarlospaco (collaborator)

devel :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:03
• Finished 2024-11-09T00:47:04
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

stable :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:07
• Finished 2024-11-09T00:47:08
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

2.0.10 :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:11
• Finished 2024-11-09T00:47:11
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

2.0.0 :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:15
• Finished 2024-11-09T00:47:15
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

1.6.20 :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:18
• Finished 2024-11-09T00:47:19
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

1.4.8 :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:22
• Finished 2024-11-09T00:47:22
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

1.2.18 :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:25
• Finished 2024-11-09T00:47:25
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

1.0.10 :-1: FAIL

Output

``` ```

IR

Compiled filesize 0 (0 bytes) ```cpp ```

Stats

• Started 2024-11-09T00:47:28
• Finished 2024-11-09T00:47:28
• Duration

AST

```nim nnkStmtList.newTree( nnkFuncDef.newTree( newIdentNode("f"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkDiscardStmt.newTree( newEmptyNode() ) ) ), nnkTemplateDef.newTree( newIdentNode("t"), newEmptyNode(), newEmptyNode(), nnkFormalParams.newTree( newEmptyNode(), nnkIdentDefs.newTree( newIdentNode("a"), newIdentNode("string"), newEmptyNode() ) ), newEmptyNode(), newEmptyNode(), nnkStmtList.newTree( nnkCall.newTree( newIdentNode("f"), nnkExprEqExpr.newTree( newIdentNode("a"), newIdentNode("a") ) ) ) ), nnkCall.newTree( newIdentNode("t"), nnkExprEqExpr.newTree( newIdentNode("a"), newLit("BUG") ) ) ) ```

Stats

• GCC 11.4.0
• Clang 14.0.0
• NodeJS 20.4
• Created 2024-11-09T00:46:34Z
• Comments 1
• Commands nim c --run -d:nimDebug -d:nimDebugDlOpen -d:ssl -d:nimDisableCertificateValidation --forceBuild:on --colors:off --verbosity:0 --hints:off --lineTrace:off --nimcache:/home/runner/work/Nim/Nim --out:/home/runner/work/Nim/Nim/temp /home/runner/work/Nim/Nim/temp.nim

:robot: Bug found in 27 mins bisecting 8 commits at 0 commits per second

[beef331]

This is expected given that any usage of an identifier expands to the parameter.

[metagn]

7811

[juancarlospaco]

Even on an identifier name left-hand side? 🤔 In which scenarios having f( "value" = "value" ) is a reasonable expansion? I think should be possible to make the compiler at least produce a warning...

[beef331]

Implementing a template that invokes a macro where you actually want "a" = "b".