Auto merge of #14664 - HKalbasi:mir, r=HKalbasi

MIR episode 4

In lowering, it now supports overloaded and arith assignment binary operators, statics. and constants in patterns. There is now 252 functions that we fail to emit mir for them, and the majority of them are due type mismatches or other deep and unrelated issues (but it isn't done yet, for example slice patterns and destructing assignment is not implemented yet).

In evaluating, it now can evaluate associated constants in traits (so now typenum's `U5::ToConst` should work), allocator functions, atomic intrinsics, and some more things. It also provides a (hacky) basis for making progress in #14275. I also added a `Interpret` code lens to `Run` and `Debug` when the experimental `interpret tests` is enabled (previously it showed result in hover, which was unusable even for debugging)

Changes in unrelated files are:
* Changes substitutions of closures, now it includes parent substs ~~before~~ after `sig_ty`.
* ~~A salsa input for retrieving the path of a file id, used in emitting stack trace for interpret result.~~
* Normalizing associated types in layout computing

3 files changed, 34 insertions, 6 deletions

diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
index 0d91548b9b3..2d5272d199d 100644
--- a/editors/code/src/commands.ts
+++ b/editors/code/src/commands.ts
@@ -422,8 +422,20 @@ export function syntaxTree(ctx: CtxInit): Cmd {
 function viewHirOrMir(ctx: CtxInit, xir: "hir" | "mir"): Cmd {
     const viewXir = xir === "hir" ? "viewHir" : "viewMir";
     const requestType = xir === "hir" ? ra.viewHir : ra.viewMir;
+    const uri = `rust-analyzer-${xir}://${viewXir}/${xir}.rs`;
+    const scheme = `rust-analyzer-${xir}`;
+    return viewFileUsingTextDocumentContentProvider(ctx, requestType, uri, scheme, true);
+}
+
+function viewFileUsingTextDocumentContentProvider(
+    ctx: CtxInit,
+    requestType: lc.RequestType<lc.TextDocumentPositionParams, string, void>,
+    uri: string,
+    scheme: string,
+    shouldUpdate: boolean
+): Cmd {
     const tdcp = new (class implements vscode.TextDocumentContentProvider {
-        readonly uri = vscode.Uri.parse(`rust-analyzer-${xir}://${viewXir}/${xir}.rs`);
+        readonly uri = vscode.Uri.parse(uri);
         readonly eventEmitter = new vscode.EventEmitter<vscode.Uri>();
         constructor() {
             vscode.workspace.onDidChangeTextDocument(
@@ -439,14 +451,14 @@ function viewHirOrMir(ctx: CtxInit, xir: "hir" | "mir"): Cmd {
         }
 
         private onDidChangeTextDocument(event: vscode.TextDocumentChangeEvent) {
-            if (isRustDocument(event.document)) {
+            if (isRustDocument(event.document) && shouldUpdate) {
                 // We need to order this after language server updates, but there's no API for that.
                 // Hence, good old sleep().
                 void sleep(10).then(() => this.eventEmitter.fire(this.uri));
             }
         }
         private onDidChangeActiveTextEditor(editor: vscode.TextEditor | undefined) {
-            if (editor && isRustEditor(editor)) {
+            if (editor && isRustEditor(editor) && shouldUpdate) {
                 this.eventEmitter.fire(this.uri);
             }
         }
@@ -473,9 +485,7 @@ function viewHirOrMir(ctx: CtxInit, xir: "hir" | "mir"): Cmd {
         }
     })();
 
-    ctx.pushExtCleanup(
-        vscode.workspace.registerTextDocumentContentProvider(`rust-analyzer-${xir}`, tdcp)
-    );
+    ctx.pushExtCleanup(vscode.workspace.registerTextDocumentContentProvider(scheme, tdcp));
 
     return async () => {
         const document = await vscode.workspace.openTextDocument(tdcp.uri);
@@ -501,6 +511,20 @@ export function viewMir(ctx: CtxInit): Cmd {
     return viewHirOrMir(ctx, "mir");
 }
 
+// Opens the virtual file that will show the MIR of the function containing the cursor position
+//
+// The contents of the file come from the `TextDocumentContentProvider`
+export function interpretFunction(ctx: CtxInit): Cmd {
+    const uri = `rust-analyzer-interpret-function://interpretFunction/result.log`;
+    return viewFileUsingTextDocumentContentProvider(
+        ctx,
+        ra.interpretFunction,
+        uri,
+        `rust-analyzer-interpret-function`,
+        false
+    );
+}
+
 export function viewFileText(ctx: CtxInit): Cmd {
     const tdcp = new (class implements vscode.TextDocumentContentProvider {
         readonly uri = vscode.Uri.parse("rust-analyzer-file-text://viewFileText/file.rs");
diff --git a/editors/code/src/lsp_ext.ts b/editors/code/src/lsp_ext.ts
index 952dbb3e88a..754d43618a4 100644
--- a/editors/code/src/lsp_ext.ts
+++ b/editors/code/src/lsp_ext.ts
@@ -64,6 +64,9 @@ export const viewHir = new lc.RequestType<lc.TextDocumentPositionParams, string,
 export const viewMir = new lc.RequestType<lc.TextDocumentPositionParams, string, void>(
     "rust-analyzer/viewMir"
 );
+export const interpretFunction = new lc.RequestType<lc.TextDocumentPositionParams, string, void>(
+    "rust-analyzer/interpretFunction"
+);
 export const viewItemTree = new lc.RequestType<ViewItemTreeParams, string, void>(
     "rust-analyzer/viewItemTree"
 );
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index 6c990f804b0..7ae8fa8ca28 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -159,6 +159,7 @@ function createCommands(): Record<string, CommandFactory> {
         syntaxTree: { enabled: commands.syntaxTree },
         viewHir: { enabled: commands.viewHir },
         viewMir: { enabled: commands.viewMir },
+        interpretFunction: { enabled: commands.interpretFunction },
         viewFileText: { enabled: commands.viewFileText },
         viewItemTree: { enabled: commands.viewItemTree },
         viewCrateGraph: { enabled: commands.viewCrateGraph },