added better error messages inspired by rustc/cargo

but not as good

mers_lib/src/program/parsed/assign_to.rs

@@ -1,10 +1,10 @@
-use crate::{parsing::SourcePos, program};
+use crate::program::{self, run::SourceRange};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct AssignTo {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub target: Box<dyn MersStatement>,
     pub source: Box<dyn MersStatement>,
 }

mers_lib/src/program/parsed/block.rs

@@ -1,10 +1,13 @@
-use crate::{info, parsing::SourcePos, program};
+use crate::{
+    info,
+    program::{self, run::SourceRange},
+};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct Block {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub statements: Vec<Box<dyn MersStatement>>,
 }
 impl MersStatement for Block {

mers_lib/src/program/parsed/chain.rs

@@ -1,11 +1,11 @@
-use crate::parsing::SourcePos;
+use crate::program::run::SourceRange;
 use crate::{info, program};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct Chain {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub first: Box<dyn MersStatement>,
     pub chained: Box<dyn MersStatement>,
 }

mers_lib/src/program/parsed/function.rs

@@ -1,4 +1,4 @@
-use crate::parsing::SourcePos;
+use crate::program::run::SourceRange;
 use std::sync::{Arc, Mutex};
 
 use crate::{
@@ -10,7 +10,7 @@ use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct Function {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub arg: Box<dyn MersStatement>,
     pub run: Box<dyn MersStatement>,
 }

mers_lib/src/program/parsed/if.rs

@@ -1,10 +1,10 @@
-use crate::{parsing::SourcePos, program};
+use crate::program::{self, run::SourceRange};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct If {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub condition: Box<dyn MersStatement>,
     pub on_true: Box<dyn MersStatement>,
     pub on_false: Option<Box<dyn MersStatement>>,

mers_lib/src/program/parsed/init_to.rs

@@ -1,11 +1,11 @@
-use crate::parsing::SourcePos;
 use crate::program;
+use crate::program::run::SourceRange;
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct InitTo {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub target: Box<dyn MersStatement>,
     pub source: Box<dyn MersStatement>,
 }

mers_lib/src/program/parsed/tuple.rs

@@ -1,10 +1,13 @@
-use crate::{info, parsing::SourcePos, program};
+use crate::{
+    info,
+    program::{self, run::SourceRange},
+};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct Tuple {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub elems: Vec<Box<dyn MersStatement>>,
 }
 impl MersStatement for Tuple {

mers_lib/src/program/parsed/value.rs

@@ -1,11 +1,11 @@
-use crate::parsing::SourcePos;
+use crate::program::run::SourceRange;
 use crate::{data::Data, program};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct Value {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub data: Data,
 }
 

mers_lib/src/program/parsed/variable.rs

@@ -1,10 +1,13 @@
-use crate::{info::Local, parsing::SourcePos, program};
+use crate::{
+    info::Local,
+    program::{self, run::SourceRange},
+};
 
 use super::{CompInfo, MersStatement};
 
 #[derive(Debug)]
 pub struct Variable {
-    pub pos_in_src: SourcePos,
+    pub pos_in_src: SourceRange,
     pub is_ref: bool,
     pub var: String,
 }