From 36aca2bf7adb5c123082cd8e7178264c5332fd2f Mon Sep 17 00:00:00 2001
From: Casey Rodarmor <casey@rodarmor.com>
Date: Thu, 7 Nov 2019 11:24:08 -0800
Subject: [PATCH] Remove now-unnecessary borrow checker appeasement (#511)

Borrow errors produced by an older version of rust forced us to create
copies of errors in the recipe resolver. The borrow checker appears to
have evolved to the point where these copies are unnecessary, so this
diff removes them.
---
 src/recipe_resolver.rs | 34 +++-------------------------------
 1 file changed, 3 insertions(+), 31 deletions(-)

diff --git a/src/recipe_resolver.rs b/src/recipe_resolver.rs
index b034a18..9c4d8cc 100644
--- a/src/recipe_resolver.rs
+++ b/src/recipe_resolver.rs
@@ -2,16 +2,6 @@ use crate::common::*;
 
 use CompilationErrorKind::*;
 
-// There are borrow issues here that seems too difficult to solve.
-// The errors derived from the variable token has too short a lifetime,
-// so we create a new error from its contents, which do live long
-// enough.
-//
-// I suspect the solution here is to give recipes, pieces, and expressions
-// two lifetime parameters instead of one, with one being the lifetime
-// of the struct, and the second being the lifetime of the tokens
-// that it contains.
-
 pub(crate) struct RecipeResolver<'a: 'b, 'b> {
   stack: Vec<&'a str>,
   seen: BTreeSet<&'a str>,
@@ -68,16 +58,7 @@ impl<'a, 'b> RecipeResolver<'a, 'b> {
   }
 
   fn resolve_function(&self, function: Token<'a>, argc: usize) -> CompilationResult<'a, ()> {
-    Function::resolve(&function, argc).map_err(|error| CompilationError {
-      offset: error.offset,
-      line: error.line,
-      column: error.column,
-      width: error.width,
-      kind: UnknownFunction {
-        function: &function.src[error.offset..error.offset + error.width],
-      },
-      src: function.src,
-    })
+    Function::resolve(&function, argc)
   }
 
   fn resolve_variable(
@@ -88,18 +69,9 @@ impl<'a, 'b> RecipeResolver<'a, 'b> {
     let name = variable.lexeme();
     let undefined =
       !self.assignments.contains_key(name) && !parameters.iter().any(|p| p.name.lexeme() == name);
+
     if undefined {
-      let error = variable.error(UndefinedVariable { variable: name });
-      return Err(CompilationError {
-        offset: error.offset,
-        line: error.line,
-        column: error.column,
-        width: error.width,
-        kind: UndefinedVariable {
-          variable: &variable.src[error.offset..error.offset + error.width],
-        },
-        src: variable.src,
-      });
+      return Err(variable.error(UndefinedVariable { variable: name }));
     }
 
     Ok(())