Rust: separate attribute macro and macro call expansions

github · redsun82 · May 14, 2025 · Apr 17, 2025 · Apr 25, 2025 · Apr 28, 2025
commit a7a887c828f1c2f7cd507606e13feaf052ff97a1
@@ -328,7 +328,11 @@ impl<'a> Translator<'a> {
            let expand_to = ra_ap_hir_expand::ExpandTo::from_call_site(mcall);
            let kind = expanded.kind();
            if let Some(value) = self.emit_expanded_as(expand_to, expanded) {
-                generated::Item::emit_expanded(label.into(), value, &mut self.trap.writer);
+                generated::MacroCall::emit_macro_call_expansion(
+                    label,
+                    value,
+                    &mut self.trap.writer,
+                );
            } else {
                let range = self.text_range_for_node(mcall);
                self.emit_parse_error(mcall, &SyntaxError::new(
@@ -655,8 +659,9 @@ impl<'a> Translator<'a> {
            } = semantics.expand_attr_macro(node)?;
            // TODO emit err?
            self.emit_macro_expansion_parse_errors(node, &expanded);
-            let expanded = self.emit_expanded_as(ExpandTo::Items, expanded)?;
-            generated::Item::emit_expanded(label, expanded, &mut self.trap.writer);
+            let macro_items = ast::MacroItems::cast(expanded)?;
+            let expanded = self.emit_macro_items(&macro_items)?;
+            generated::Item::emit_attribute_macro_expansion(label, expanded, &mut self.trap.writer);
            Some(())
        })();
    }

@@ -217,7 +217,7 @@ final class MacroCallCfgNode extends Nodes::MacroCallCfgNode {

  /** Gets the CFG node for the expansion of this macro call, if it exists. */
  CfgNode getExpandedNode() {
-    any(ChildMapping mapping).hasCfgChild(node, node.getExpanded(), this, result)
+    any(ChildMapping mapping).hasCfgChild(node, node.getMacroCallExpansion(), this, result)
  }
 }


@@ -75,7 +75,7 @@ class StructPatChildMapping extends ParentAstNode, StructPat {
 }

 class MacroCallChildMapping extends ParentAstNode, MacroCall {
-  override predicate relevantChild(AstNode child) { child = this.getExpanded() }
+  override predicate relevantChild(AstNode child) { child = this.getMacroCallExpansion() }
 }

 class FormatArgsExprChildMapping extends ParentAstNode, CfgImpl::ExprTrees::FormatArgsExprTree {

@@ -160,7 +160,7 @@ private predicate guaranteedMatchPosition(Pat pat) {
    parent.(OrPat).getLastPat() = pat
    or
    // for macro patterns we propagate to the expanded pattern
-    parent.(MacroPat).getMacroCall().getExpanded() = pat
+    parent.(MacroPat).getMacroCall().getMacroCallExpansion() = pat
  )
 }


@@ -143,7 +143,7 @@ class LetStmtTree extends PreOrderTree, LetStmt {
 }

 class MacroCallTree extends StandardPostOrderTree, MacroCall {
-  override AstNode getChildNode(int i) { i = 0 and result = this.getExpanded() }
+  override AstNode getChildNode(int i) { i = 0 and result = this.getMacroCallExpansion() }
 }

 class MacroStmtsTree extends StandardPreOrderTree, MacroStmts {
@@ -685,7 +685,7 @@ module PatternTrees {
  }

  class MacroPatTree extends PreOrderPatTree, MacroPat {
-    override Pat getPat(int i) { i = 0 and result = this.getMacroCall().getExpanded() }
+    override Pat getPat(int i) { i = 0 and result = this.getMacroCall().getMacroCallExpansion() }
  }

  class OrPatTree extends PostOrderPatTree instanceof OrPat {

diff --git a/rust/ql/lib/codeql/rust/elements/MacroCall.qll b/rust/ql/lib/codeql/rust/elements/MacroCall.qll
@@ -60,7 +60,7 @@ module Impl {

    /** Holds if this node is inside a macro expansion. */
    predicate isInMacroExpansion() {
-      this = any(MacroCall mc).getExpanded()
+      this = any(MacroCall mc).getMacroCallExpansion()
      or
      this.getParentNode().isInMacroExpansion()
    }
-Original file line number
+Diff line change
@@ -328,7 +328,11 @@ impl<'a> Translator<'a> {
                 let expand_to = ra_ap_hir_expand::ExpandTo::from_call_site(mcall);
                 let kind = expanded.kind();
                 if let Some(value) = self.emit_expanded_as(expand_to, expanded) {
-                    generated::Item::emit_expanded(label.into(), value, &mut self.trap.writer);
+                    generated::MacroCall::emit_macro_call_expansion(
+                        label,
+                        value,
+                        &mut self.trap.writer,
+                    );
                 } else {
                     let range = self.text_range_for_node(mcall);
                     self.emit_parse_error(mcall, &SyntaxError::new(
@@ -655,8 +659,9 @@ impl<'a> Translator<'a> {
                 } = semantics.expand_attr_macro(node)?;
                 // TODO emit err?
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            aibaars
  

      

      

      


        Apr 30, 2025


      
    

  


        
      
  
  
  
    

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      It would be nice to register any failure reason as a diagnostic, so we can keep track of how many macro expansions were successful.
    
  
  


    

        
      
  
  
    
  
  
  
    
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        Apr 30, 2025


      
    

  


        
      
  
  
  
    

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      after looking a bit at the rust analyzer code, I have the feeling the err in the ExpandResult gets recovered again in parse_macro_expansion_error which is called by our emit_macro_expansion_parse_errors function called just below. So I think we should ignore the err here, as otherwise we would be emitting a diagnostic twice about it.
    
  
  


    

        
      
  
  
    
  
  
  
    
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      Ah that makes sense. I guess that leaves the ? after the cast as a potential error that may be worth reporting. I suppose the result is always a MacroItem, but perhaps it could be just an Item if the macro expands to a single item, or an Error if something went wrong (although in that case I'd expect a parse error to be reported).
    
  
  


    

        
      
  
  
    
  
  
  
    
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        Apr 30, 2025


      
    

  


        
      
  
  
  
    

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      yeah, maybe reporting an error there makes sense, just to be defensive. I think attribute and derive macros will always expand to MacroItems, as that's the only context in which they appear.
    
  
  


    

        
      
  
  
    
  
  
  
    
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                 self.emit_macro_expansion_parse_errors(node, &expanded);
-                let expanded = self.emit_expanded_as(ExpandTo::Items, expanded)?;
-                generated::Item::emit_expanded(label, expanded, &mut self.trap.writer);
+                let macro_items = ast::MacroItems::cast(expanded)?;
+                let expanded = self.emit_macro_items(&macro_items)?;
+                generated::Item::emit_attribute_macro_expansion(label, expanded, &mut self.trap.writer);
                 Some(())
             })();
         }
-          Expand Down